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On the Lighter Side => New Theories => Topic started by: David Cooper on 22/05/2021 06:41:42

Title: Does this experiment disprove relativity?
Post by: David Cooper on 22/05/2021 06:41:42
Mod edit: Topic split off Can you measure the one way speed of light without synchronised clocks?
https://www.thenakedscientists.com/forum/index.php?topic=82170

Imagine lots of clocks being made immediately after the big bang which are then separated from each other by the expansion of space, leaving us with a universe full of clocks rather than galaxies, but all spread out through space evenly. We could take any pair of these clocks and accelerate them towards each other with equal force, and when they meet up they would both agree about what the time is. But that would only apply if the clocks were all at rest in the expanding space. What happens if they were all moving through space at high speed in the same direction? Well, in some cases when you bring two of these clocks together, you’ll be accelerating one and decelerating the other, so they will not agree on the time when they meet up. If those clocks existed, this would provide us with a means to pin down the absolute speeds of motion of the clocks, and once we have those, measuring the one-way speed of light relative to a host of different types of apparatus (and knowing that you're getting the correct answer) becomes trivial..

(We can’t go back to the big bang to place lots of clocks there to do that experiment for real, but space is still expanding, and it’s doing that here. This means that we should be able to carry out essentially the same experiment right here and now, as I set out recently elsewhere.)

If you’re having difficulty understanding why the clocks in some cases would have to go out of sync when you bring them together, this must happen in order to conform to the rules of the twins paradox. Imagine that when the clocks are created right back at the time of the big bang, they all send out watches in two opposite directions. Set A of these watches are all moving in the same direction as each other and at the same speed, while set B of watches were sent out at the same speed but in the opposite direction. Let’s suppose that the clocks are stationary and the watches are moving. If a set A watch meets a set B watch, they will agree with each other about the time, but if any watch meets a clock, the time on the watch will lag behind the time on the clock due to its speed of movement through space. How can I prove that? Well, in a case where a set-A watch passes a clock, then passes a set-B watch later on, and then the set-B watch passes the clock later still, we have the twins paradox experiment being carried out by those three timers. We could have scenarios where the clocks and set-A watches are both ticking at the same rate (which means the clocks aren’t at rest), but the set-B watches would have to be ticking slower than that in order to produce the required result for the twins paradox. Once you understand the necessity for that to happen, you should then be able to see that when clocks/watches pass each other, the amount by which they disagree on the time provides information about their absolute speeds of motion through space. Relativity is cracked wide open by this.
Title: Re: Does this experiment disprove relativity?
Post by: jeffreyH on 22/05/2021 12:39:17
David, you really have cracked the art of unnecessarily complicating an issue.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 22/05/2021 15:22:46
Imagine lots of clocks being made immediately after the big bang which are then separated from each other by the expansion of space …
If those clocks existed, this would provide us with a means to pin down the absolute speeds of motion of the clocks, and once we have those, measuring the one-way speed of light relative to a host of different types of apparatus (and knowing that you're getting the correct answer) becomes trivial..
There are such clocks (you can look at the apparent ages of the galaxies in various directions with similar redshift).  This cosmological frame is well known as is our motion relative to it (known as peculiar motion). But the frame isn’t inertial except locally, so the usual operations one can perform with objects in inertial frames don’t work. In particular, the peculiar velocity an object will degrade over time, barring external forces pushing it along. Newton’s laws  of motion don’t apply to such a frame. An illustration of this below.

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Imagine that when the clocks are created right back at the time of the big bang, they all send out watches in two opposite directions. Set A of these watches are all moving in the same direction as each other and at the same speed, while set B of watches were sent out at the same speed but in the opposite direction.
There is no space at the big bang, so no concept of speed. The watches will just be right by some other clock going in the same direction, and thus none of them will have any peculiar velocity.
So let’s change it just a tiny bit and wait one second.  All the clocks are created at the big bang, and one second later, they all send out watches in random opposite directions, all synced at one second. Say they are ejected at half light speed, and let’s keep it simple and say expansion is flat: no acceleration or deceleration. In reality, there was significant slowing of exansion at the one-second time.
So there’s our reference clock X1, and a second clock X2 receding from X1 at half light speed. X1 now ejects a pair of watches, one of which is chasing X2.  The two are relatively stationary (their proper separation over time remains fixed) and 150,000 km apart, but X2 (all the X clocks) have zero peculiar velocity, which all the watches have a peculiar velocity of 0.5c.  But the watch and X2 will remain forever 150,000 km apart, so an hour later, the watch is already almost stationary.  This is what I mean by its speed (relative to the cosmological frame) degrading over time.  So any object today with significant peculiar velocity has to have been accelerated somewhat recently. Nothing can have retained high speed from long ago. So yes, you could have a universe of clocks all going north at some stupid high speed, but only by waiting until recently and then accelerating them.  This of course would violate conservation of momentum, so the cosmological frame is actually easily determined simply by noting the average momentum of the stuff all around us. The larger the radius of space you include in that average, the more accurate the measurement. Go all the way to the radius of the visible universe and the measurement is accurate down to a few km/sec.

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If a set A watch meets a set B watch, they will agree with each other about the time, but if any watch meets a clock, the time on the watch will lag behind the time on the clock due to its speed of movement through space. How can I prove that?
If the watches were ejected at time zero, there would be no meeting of anything. Any watch in the presence of a clock has always been in its presence.  If they were ejected say one second after the big bang, then yes, they’d meet clocks but the time difference will be off by less than a second. It was moving at a significant speed for such a very short time and had no real time to accumulate any serious dilation.

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Well, in a case where a set-A watch passes a clock, then passes a set-B watch later on, and then the set-B watch passes the clock later still, we have the twins paradox experiment being carried out by those three timers.
That analysis works if the watches were delay ejected. It doesn’t work if they were immediately ejected since they would never cross paths with a clock. All the watches would have zero peculiar velocity and would not meet anything that hasn’t always been in its presence.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 22/05/2021 22:53:42
Yes, per RoS, a rigid rotating cylinder will be twisted relative to a frame in which it has linear motion along its axis of rotation, which is not immediately intuitive.

I should add that if you're travelling with it you won't be able to measure the twisting due to Doppler-shift on the light coming from the two ends, and the atoms in the shaft are "fooled" in the same way with their forces applying to the ones around them, still "thinking" that they're the same distance away from their neighbours regardless of the amount or lack of twist.

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There is no space at the big bang, so no concept of speed. The watches will just be right by some other clock going in the same direction, and thus none of them will have any peculiar velocity.
So let’s change it just a tiny bit and wait one second.

At the start of an earlier paragraph I said "Imagine lots of clocks being made immediately after the big bang". That word "after" indicates a delay before the clock creation that could be as little as a second, but we could give it a year or more to put some space between all the clocks: if our set A and B watches are sent out at relativistic speed it's sufficient for the clocks to be created early on. We could also just have trillions of clocks created at that moment and sent off in random directions at random speeds. Some of them can later be classed as set A watches, set B watches and set C (clocks). If we keep that universe sufficiently empty, the clocks will soon be far enough apart for their gravitational pull on each other to be irrelevant, so they won't be pulled off course and won't clump together.

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This is what I mean by its speed (relative to the cosmological frame) degrading over time. ... Nothing can have retained high speed from long ago.

Well, if that second statement was correct, you'd have identified another way of pinning down absolute speed in an expanding universe because all the clocks would automatically slow down until they're at rest. You would eventually reach a point where the clocks are so spread out that none of them can pass each other any more as they aren't able to close the gaps faster than the spaces between them are expanding, but you've missed something important: they still have their initial speeds of motion through space, and if we go back to an earlier time when they are still able to pass each other, set A watches will continue to pass set B watches at the same relative speed as they did early on: that speed through space does not degrade. The result is that we can continue to have an A, B and C clock carry out a twins paradox experiment at any time up until clocks can no longer meet, and those twins paradox experiments can be of very short duration.

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So any object today with significant peculiar velocity has to have been accelerated somewhat recently. Nothing can have retained high speed from long ago.

This too makes it clear that you've miscalculated: for all those ancient speeds to have been lost while the clocks are still able to pass each other, they would have to have slowed to a lower absolute speed, all homing in on being at rest. That won't actually happen, but if it did you would have found another way to pin down absolute speeds. In reality the speeds are maintained and the differences in the times on passing clocks reveals their absolute speeds (or one component of them - you still need it for another two dimensions before you have the correct figure for it, but you'd get that from cases of clocks passing each other in other directions).

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If they were ejected say one second after the big bang, then yes, they’d meet clocks but the time difference will be off by less than a second. It was moving at a significant speed for such a very short time and had no real time to accumulate any serious dilation.

After 14 billion years there would still be watches passing clocks at the same relative speed as was happening when the universe was two seconds old, (assuming no collisions or slowing from dust, though in this thought experiment we can use infinitesimally small clocks and we can create and set them moving apart after a year after the big bang.) With set A watches moving at 0.866c relative to the clocks, and set B watches doing the same in the opposite direction and with those relative speeds always being maintained at moments where they're passing each other, we will have clocks registering 14 billion years passing while the watches passing them have only counted up 7 billion years if the clocks are at rest in space. If we have set A watches at rest instead, then they will have registered 14 billion years passing when they pass clocks that have at that moment registered 7 billion years passing, and when set  A watches pass set B watches with the As registering 14 billion years, the Bs will only have registered 2 billion years passing. If you look at our universe today it should be obvious that watches moving at 0.866c today would still be passing clocks here if enough were created at the start for them to be sufficiently well distributed, and they would not have lost any of that relative speed to the expansion of space.

But suppose I'm wrong. Light loses energy to expansion and gets red shifted - it doesn't slow down, but it loses energy. Does matter lose energy in the same way or does it slow down. You can't red shift matter by spreading it out as it will continue to pull back to its preferred length in a way that light doesn't do, but how could it slow down by being stretched if it keeps pulling back to the original length? If it's at rest and is stretched, it will pull back together without changing its speed, so it can't be losing energy to the expansion. That means the expansion has to do work. Well, that's a nice spinoff issue to explore.

For now though, let's just think down a path where there is slowing of objects caused by expansion. (I don't think there will be, but I can't rule out the possibility, so lets work to the premise that there is such slowing.) The watches would all slow down closer to being at rest, allowing us to pin absolute speeds down to a reduced range just by doing that, but set A or B or both would also have spent a considerable amount of their past moving at high relativistic speed, leading to them recording a lot less time passing than the clocks. They may be passing the clocks slowly after 14 billion years, but their timings could still differ by millions of years (or tens or hundreds of millions of years) rather than billions, but even in the worst case scenario that would still reveal extremely precise information about their absolute speeds, so the method would work regardless. What we need to do now is carry out an equivalent experiment in a region of expanding space today, and I've already shown how that could be done. (If there is no local expansion, then there would need to be plate boundaries between galaxies where the expansion happens, and while that used to be what physicists thought was happening, they later ruled it out and currently believe that the expansion is happening smoothly everywhere [though not necessarily uniformly].)
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 25/05/2021 00:36:52
Well, if that second statement was correct, you'd have identified another way of pinning down absolute speed in an expanding universe because all the clocks would automatically slow down until they're at rest.
The physics community calls it peculiar velocity. If it makes you happy to call it absolute speed, go for it. It is very much a preferred coordinate system since any pair of observers anywhere can find it without communication. Yes, all the galaxies have nearly zero peculiar velocity, with what they have being due to recent accelerations towards nearby masses, not due to anything imparted near the time of the big bang.
There are several ways to pin it down, but CMB isotropy has always been the simplest.

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we could give it a year or more to put some space between all the clocks
A year is fine
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You would eventually reach a point where the clocks are so spread out that none of them can pass each other any more as they aren't able to close the gaps faster than the spaces between them are expanding
With the exception of the addition of dark energy, any objects decreasing their proper separation will forever continue to decrease their proper separation. Expansion cannot reverse that. If expansion is outpacing peculiar motion, then it always was from the moment of last proper acceleration.
Dark energy is the exception to this, but I thought we were considering a reasonably simple case of flat expansion neither accelerating nor decelerating.

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but you've missed something important: they still have their initial speeds of motion through space, and if we go back to an earlier time when they are still able to pass each other, set A watches will continue to pass set B watches at the same relative speed as they did early on
No they don’t. Their peculiar velocities drop quickly, as I’ve pointed out in prior posts.
Suppose comoving (‘stationary’) primary clocks P, Q,R, situated such that their proper separation increases at a rate of 1.094 light seconds per second. Q is our observer. 1.094c is not a velocity as measured in an inertial coordinate system. It is a recession rate between two ‘stationary’ objects.
At T=1 year, P and R each launch at Q at 0.8c an A and B clock respectively. These two clocks get to Q after 13.8 billion years, are stationary to an absurd number of digits, and are slow by 8 months. The majority of the dilation takes place in the first year or two after being fired off. After that, their peculiar velocities have dropped to a point where time dilation fades away.
Figuring that out requires some interesting coordinate changes from comoving coordinates to inertial coordinates.

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for all those ancient speeds to have been lost while the clocks are still able to pass each other, they would have to have slowed to a lower absolute speed, all homing in on being at rest.
I perhaps cannot convince you of this, but your mistake seems to be applying Newtons laws of inertial motion to a non inertial coordinate system. How do you defend this assertion?

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With set A watches moving at 0.866c relative to the clocks, and set B watches doing the same in the opposite direction and with those relative speeds always being maintained ...
But those speeds are maintained only in Minkowski physics, not in the expanding metric.

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But suppose I'm wrong. Light loses energy to expansion and gets red shifted - it doesn't slow down, but it loses energy.
Light only loses energy relative to the cosmological (or 'comoving') frame, not in an inertial one. Non-inertial frames play by different rules. In some non-inertial frames, moving things increase in speed. Light might stop, turn around, and go back the way it came.

About 2 3/4 BLY away there’s a galaxy receding from us at 0.2c (inertial coordinates). I fire a rock at it at 0.2c. At what point is it going to accelerate and actually begin to catch up to that galaxy?  It will never catch up to it, and that galaxy is ‘stationary’ (cosmological coordinates). Saying that it not only will, but will pass by it at 0.2c, is a violation of the inertial laws of motion.

I had trouble looking for a reference discussing this. Did find this one where somebody asks “I've read that the momentum of particles declines due to the universe's expansion. " but I wish he’d show where he read that. The reply confirms it and goes into the math which is over my head.
https://physics.stackexchange.com/questions/221231/in-what-manner-does-momentum-of-a-particle-with-mass-decrease-due-to-spatial-exp
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 26/05/2021 00:46:33
The physics community calls it peculiar velocity. If it makes you happy to call it absolute speed, go for it.

For the content of the universe to slow to that peculiar velocity or absolute speed automatically rejects STR. If the sets A, B and C all end up at rest relative to each other, some have lost more speed than others, and the ones that have lost the most speed will have clocks with the least time recorded on them. The difference would show, and they'd all end up practically at rest too.

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but you've missed something important: they still have their initial speeds of motion through space, and if we go back to an earlier time when they are still able to pass each other, set A watches will continue to pass set B watches at the same relative speed as they did early on
No they don’t. Their peculiar velocities drop quickly, as I’ve pointed out in prior posts.

I see it now. If I roll a ball along an expanding track where the track expands at a particular point - let's make it telescopic - the ball runs up to the place where the expansion occurs and it's going at a certain rate relative to the track, then it moves onto the part that's coming out from inside and it's now moving at a lower speed relative to the part of the track it's gone onto, so its speed relative to that has gone down. So, if that's the mechanism, then with an expanding track all balls rolling along it will end up at rest relative to the local track. So, the content of expanding space (ignoring radiation) will end up close to being at rest, and that means that when a particle in a particle accelerator is made to move at 0.99c relative to us, it really is moving close to the speed of light and there is no possibility that we are the ones moving at close to the speed of light while that particle is at rest.

The problem here is that this already rules out STR. For STR to be viable, that slowing down of material until it's all close to being at rest simply could not happen. The set A and set B watches have slowed down and ended up at rest relative to the clocks, or alternatively, if the set A watches were stationary to begin with, then the clocks and set B watches have slowed down instead with the set B watches slowing most. In these two rival cases, there would be different timing differences which would tell you which ones were closest to being at rest initially. They might now be essentially at rest and no longer passing each other, but you could still find out what the timing differences are by comparing different timers near to each other.

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for all those ancient speeds to have been lost while the clocks are still able to pass each other, they would have to have slowed to a lower absolute speed, all homing in on being at rest.
I perhaps cannot convince you of this, but your mistake seems to be applying Newtons laws of inertial motion to a non inertial coordinate system. How do you defend this assertion?

I didn't think that matter would slow down in expanding space, but I win both ways because if it does, it still reveals that there are absolute speeds, so it never bothered me whether they slow down or not - I'm happy with it either way, and now it looks as if they do slow down, which is absolutely fine with me. Going back to the telescopic track, a ball sitting on the track and not running along it will remain at rest relative to the track. A ball running along the track will slow down and end up almost at rest too. With matter in expanding space doing the same thing, that puts almost all of it almost at rest, apart from the small amount being jetted out of quasars and the like at relativistic speed.

I'm quite happy now to go accept that things slow down in expanding space - you've helped resolve that for me. The experiment reveals absolute speed by reducing the speed of stuff closer and closer to absolute rest in the local space fabric, so we still reveal absolute speeds approximately, and with the timers in the thought experiment we could narrow it down further by looking at which clocks have recorded the most time passing, because those are the ones closest to being completely stationary as the started out that way.

So, we have a theoretical method for pinning down absolute speed regardless, and it shows them in two different ways: the timing differences and the slowing of most matter to rest. The next step is to exploit the ongoing expansion of space to measure its local expansion rate, and, if it is expanding here, to use that to pin down the absolute speed of the measuring apparatus and then use the result to measure the one-way speed of light relative to the apparatus.

By putting two clocks a certain distance apart and allowing space to expand between them, but in this case we aren't moving the clocks relative to each other, so we don't need to care about their speed through space being reduced by by the expansion. If they're both at rest to begin with, they remain at rest at the end. If they're both moving at high speed to the left to begin with, they're still both moving at high speed to the left when it ends, and if they've lost a tiny amount of that, it doesn't matter: they will both lose exactly the same amount as each other through that process. If the clocks are at rest in space, they will retain their synchronisation (which was originally set by having a comoving observer sene out a signal from half way between them - their signals at the end of the experiment will reach the central observer simultaneously). If the clocks are moving to the left at high speed, they both have to send a signal an extra distance across the added space between them back to the observer at the midpoint between them, and that signal crosses that extra distance in opposite directions with one taking longer to do so than the other, leading to them not reaching the observer simultaneously. That allows their absolute speed to be measured, and if it comes out as non-zero, we can then use that information to measure a one-way speed of light relative to the clocks which is not c. If it doesn't come out as non-zero, then either there is no local expansion or the apparatus was at rest, in which case we can redo the experiment after accelerating the apparatus to a different speed, at which point we will either prove that there is no local expansion (though we'd have to do this in multiple directions to be sure of that), or we would then be able to measure a non-zero one-way speed of light relative to the apparatus with it moving at its new speed.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 27/05/2021 01:21:08
I see it now. If I roll a ball along an expanding track where the track expands at a particular point - let's make it telescopic - the ball runs up to the place where the expansion occurs and it's going at a certain rate relative to the track, then it moves onto the part that's coming out from inside and it's now moving at a lower speed relative to the part of the track it's gone onto, so its speed relative to that has gone down.
I find no fault with that analogy.  The number of places where the telescoping occurs can be one place with a big speed difference or a bunch of little gradients. The limit as the discreet gradients approaches being continuous is the same as the coarse case.
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So, if that's the mechanism, then with an expanding track all balls rolling along it will end up at rest relative to the local track.
Arbitrarily close to being at rest, but never completely at rest, else the history of the object would not be able to be extrapolated by its current state. You do say ‘close to’ in your post, so you get this point.
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So, the content of expanding space (ignoring radiation) will end up close to being at rest, and that means that when a particle in a particle accelerator is made to move at 0.99c relative to us, it really is moving close to the speed of light and there is no possibility that we are the ones moving at close to the speed of light while that particle is at rest.
If speed is measured relative to the cosmological frame, then yes. I assume you mean this, but without that being explicit, the statement is ambiguous.
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The problem here is that this already rules out STR. For STR to be viable, that slowing down of material until it's all close to being at rest simply could not happen.
STR makes no mention of a cosmological frame or peculiar velocity, and you know this. Relative to any inertial coordinate system in Minkowski spacetime, an object, in the absence of force, will maintain its velocity indefinitely. The cosmological frame is not inertial and so Newton’s laws of inertial don’t particularly apply to it, much in the same way they don’t apply to a host of assorted varieties of non-inertial coordinate systems. And our simplified example with gravity and dark energy removed is in fact Minkowskian. The real universe has those two things, making it not Minkowskian except locally.
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The set A and set B watches have slowed down and ended up at rest relative to the clocks
Nearly at rest...
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or alternatively, if the set A watches were stationary to begin with, then the clocks and set B watches have slowed down instead with the set B watches slowing most. In these two rival cases, there would be different timing differences which would tell you which ones were closest to being at rest initially.
Agree, the unaccelerated clocks will always show more time than the accelerated ones. Just not much.
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They might now be essentially at rest and no longer passing each other, but you could still find out what the timing differences are by comparing different timers near to each other.
My example had 8 months difference after all 3 clocks met after 13 billion years. Even less if they’re ejected before the one year mark. The longer you wait to eject them, the longer they take to slow down. The experiment you describe at the end of your post would take many millions of years, when the thing it is trying to detect is already known and readily measured.
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I win both ways
Ah, It’s a win/lose thing with you. I kinda suspected. Science isn't about winning. It's about making useful predictions. What useful prediction does your philosophy make?

Yes, there is an objective non-inertial coordinate system that can be determined by multiple parties arbitrarily separated, without communication. I cannot think of another coordinate system with this property. All objects tend to come to rest in this frame, which makes it an excellent candidate for an absolute frame. This has been known since Hubble’s time. You’re just now getting on that bandwagon? I thought you hung with the nLET crowd...

I feel that an absolute coordinate system should in addition order all spacetime events, and should assign absolute times to those events, not relative times.  The cosmological frame falls short on both of those, but it seems to be the preferred candidate for an absolute frame regardless.
It fails to order all events (such as those inside black holes), and times are relative to Earth time, which would not be agreed upon by said non-communicating distant observer.

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it still reveals that there are absolute speeds
One could measure time relative to a clock at the average gravitational potential (which isn’t constant over time), but then some clocks would be dilated faster, not slower. Without an absolute clock, there are not absolute speeds.

I feel I am on shaky ground on that one. The lack of an objective clock is a problem, but we know c to an amazing number of digits, and so in theory time is just m/c. Of course, we define the meter based on our clock, so that’s a circular definition of time. Jury is out I think.
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apart from the small amount being jetted out of quasars and the like at relativistic speed.
There are no quasars anymore, so stuff accelerated by them has since slowed, but there still are things being accelerated to absolutely stupid speeds. They found some object that was regularly firing off bullets the mass of Jupiter at nearly light speed.
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So, we have a theoretical method for pinning down absolute speed regardless
We have a much more practical method than a mere thought experiment. Look at the web. Our peculiar velocity is around 390 km/sec, much slower than it was when the T-rex was around.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 27/05/2021 23:20:56
STR makes no mention of a cosmological frame or peculiar velocity, and you know this

The point is though that STR is not compatible with this universe. There are clearly absolute speeds because things are slowing down until they're practically at rest, so STR cannot even apply locally. It denies the very idea of there being such a thing as at rest.

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Agree, the unaccelerated clocks will always show more time than the accelerated ones. Just not much.

If the clocks were moving and one set of the watches were then decelerated when they were sent out, those decelerated watches will be the ones with the most time displayed on them, but you would call them accelerated. Their timings would reveal what actually happened to them.

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My example had 8 months difference after all 3 clocks met after 13 billion years. Even less if they’re ejected before the one year mark. The longer you wait to eject them, the longer they take to slow down.

It's a thought experiment in which we could add a scientist who reads the times on the clocks without having to wait billions of years. The results would show up within seconds of the clocks and watches being created and sent out because some of them would be ticking half as often as others, and it would take a long time for that difference to reduce.

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The experiment you describe at the end of your post would take many millions of years, when the thing it is trying to detect is already known and readily measured.

It wouldn't take anything like that long to do the experiment. A month would be sufficient to measure the difference.

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Ah, It’s a win/lose thing with you. I kinda suspected. Science isn't about winning. It's about making useful predictions. What useful prediction does your philosophy make?

It's about winning an argument. The point is that this universe clearly has to have absolute speeds of motion in it, whereas STR denies them. You want to have STR in this universe, but you can't logically have that. And then you misuse the word philosophy by implying that your position isn't philosophical while mine is. Science is very much philosophy, but the relevant distinction here is between good philosophy and bad philosophy, and when it tolerates contradictions it becomes the latter. I have described an experiment that could be carried out in the real universe in the not-too-distant future which could pin down the absolute speed of motion of the apparatus and lead to correct measurement of the one-way speed of light relative to it, and you think that has nothing to do with useful predictions while you continue to back a disproved theory. Two sets of the same apparatus being set up and run in the exact same manner but producing different results due to their different absolute speeds of travel is something that LET predicts but STR does not predict. That is really big.

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This has been known since Hubble’s time. You’re just now getting on that bandwagon?

Clearly that is not the case, because STR is still being backed by everyone in physics and they're refusing to accept that it's been blown out of the water. Soon they'll all be playing the same game, making out that they always knew STR was wrong and never intended anyone to think it applied to the real universe, but just look back at the history of abuse of people who've objected to STR here and everywhere else by boorish thugs insisting that STR is right and that the objectors are crackpots. That's where the scandal is, quite apart from systematically miseducating the public in a manner that's totally unethical.

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It fails to order all events (such as those inside black holes), and times are relative to Earth time, which would not be agreed upon by said non-communicating distant observer.

That distant observer would simply convert between the two times and adjust for minor accelerations, so it's not an issue. But the events in black holes fit with it perfectly: you simply use a theory that makes incorrect predictions about what's going on inside black holes, and that's what creates problems for you as you imagine that stopped clocks continue to tick and that their proper time never runs slow.

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One could measure time relative to a clock at the average gravitational potential (which isn’t constant over time), but then some clocks would be dilated faster, not slower. Without an absolute clock, there are not absolute speeds.

Without an absolute clock, the universe would fall apart through event-meshing failures in an instant. But absolute speeds could be pinned down in the way I spelt out even without caring about absolute time as it's sufficient to compare those absolute speeds with light in the local space and express it as a proportion of c.

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So, we have a theoretical method for pinning down absolute speed regardless
We have a much more practical method than a mere thought experiment.

It isn't just a thought experiment: it could be carried out for real, and within this century.

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Look at the web. Our peculiar velocity is around 390 km/sec, much slower than it was when the T-rex was around.

What's stopping you from just admitting that STR is a disproved theory (in that it's incompatible with this universe)? You're almost there now.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 28/05/2021 22:37:32
The point is though that STR is not compatible with this universe.
STR covers the special case of Minkkowskian spacetime. With the exception of physical singularities, the universe is Minkowskian only locally, and the theory does not assert otherwise. The universe as a whole is not covered under ‘locally’, so one has to use the general theory, not the special case one. STR never claims to cover the general case, and yet you never seem to rag on GR which does. Is your case so pathetic that the only way you can bring it down is suggest out that the universe as a whole obviously has gravity in it when STR asserts that it does not? Drop an apple on your head. That's am empirical result that STR doesn't predict. You've won, and without all this needless complication.

STR in fact makes no metaphysical assumptions or conclusions, and all your arguments seem to be based on metaphysical assumptions, not empirical ones.
So if you with to continue foaming on about STR being wrong, be a little explicit about what observations you think it predicts and what actually will be observed. Our little thought experiment has gravity and dark energy removed, so it is actually Minkowskian as a whole. STR would cover such a simplified universe, so we can refer to that example if you wish. But the real universe has gravity and such, making GR the applicable theory.
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It's a thought experiment in which we could add a scientist who reads the times on the clocks without having to wait billions of years. The results would show up within seconds of the clocks and watches being created and sent out because some of them would be ticking half as often as others, and it would take a long time for that difference to reduce.
The scientist can only read the clocks once when they pass by him. And the accelerated ones will be behind, exactly as STR predicts.
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It's about winning an argument.
Then suggest an empirical test in a universe without gravity and such that STR predicts incorrectly. Can’t do that? Then you haven’t won. Asserting that STR denies some metaphysical concept (absolute motion) is just a strawman since it isn’t a metaphysical theory.
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Science is very much philosophy, but the relevant distinction here is between good philosophy and bad philosophy, and when it tolerates contradictions it becomes the latter.
But STR doesn’t make any philosophical assertions. It’s all empirical. So it cannot be self contradictory on the philosophical front. It has to be empirical. Anything beyond that, and everything you push, is metaphysical, and thus just an interpretation of relativity, not a contradiction of it. I’m not saying your interpretation is wrong, so there is no ‘winning’ in it for me. I’m just saying that your interpretation cannot pony up a since empirical difference.


Concerning inconsistencies with your interpretation in the real universe (not the thought-experiment one with no gravity in it):
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It fails to order all events (such as those inside black holes)
But the events in black holes fit with it perfectly: you simply use a theory that makes incorrect predictions about what's going on inside black holes, and that's what creates problems for you as you imagine that stopped clocks continue to tick and that their proper time never runs slow.
So you’re asserting physics is locally measurably different at different potentials? You’d notice time slowing? Seriously? How about at speed then?  If I move at .99c, will I notice everything moving slow? Just wondering where you stand on this.
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Times are relative to Earth time, which would not be agreed upon by said non-communicating distant observer. One could measure time relative to a clock at the average gravitational potential (which isn’t constant over time), but then some clocks would be dilated faster, not slower. Without an absolute clock, there are not absolute speeds.
That distant observer would simply convert between the two times and adjust for minor accelerations, so it's not an issue.
You misunderstand. I’m talking about time as measured by clocks at Earth potential and a different potential (neither at zero potential) of the distant observer. Both are stationary relative to the comoving coordinate system. We’re both measuring the ‘absolute’ speed of some mutually visible object, and getting different numbers because our clocks (neither of which has ever accelerated) tick at different rates. Clearly speed is relative if we’re getting different answers. Where’s the absolute clock that measures the time it takes the object to go distance X?
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Without an absolute clock, the universe would fall apart through event-meshing failures in an instant.
I would just have said that absolute speeds are meaningless without such a clock, but if you want the universe to fall apart due to your assertions, who am I to argue?
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express it as a proportion of c.
Light doesn’t move at c in your absolute universe. It only moves at c at zero potential. This has been demonstrated. Relativity would say that it empirically moves at c ‘here’, using local rulers and clocks, but at least one of those is wrong in your interpretation.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 30/05/2021 02:00:28
STR covers the special case of Minkkowskian spacetime. With the exception of physical singularities, the universe is Minkowskian only locally, and the theory does not assert otherwise.

The whole point though is that it doesn't even apply locally in an expanding universe because an expanding universe forces there to be absolute speeds of motion at every locality, including any in which there is no expansion. So STR is gone and needs a replacement. LET continues to fit the facts though, so which is the better of the two theories? We have made progress by eliminating STR from the inquiry.

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STR never claims to cover the general case, and yet you never seem to rag on GR which does. Is your case so pathetic that the only way you can bring it down is suggest out that the universe as a whole obviously has gravity in it when STR asserts that it does not?

Pathetic? Showing that STR doesn't work in this universe is the very opposite of pathetic. It's clinging to STR after it's been shown not to fit this universe that would be pathetic. In science you make progress by looking to see what can be ruled out and then you look at the ramifications. The time dimension has gone too, replaced by absolute time, so what does that do for GTR? But that's a discussion for another thread.

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STR in fact makes no metaphysical assumptions or conclusions, and all your arguments seem to be based on metaphysical assumptions, not empirical ones.

You've got that entirely the wrong way round. STR's is supposedly just it's two postulates, but they're so ambiguous that they also describe LET if you interpret them in a the way that doesn't result in contradictions. That's why STR's additional dogma is so important for distinguishing it from LET (while Einstein and others were absolutely clear that it is not LET): STR it denies the existence of absolute time and absolute speeds of motion, and in doing so it is making metaphysical assumptions and conclusions.

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So if you with to continue foaming on about STR being wrong, be a little explicit about what observations you think it predicts and what actually will be observed. Our little thought experiment has gravity and dark energy removed, so it is actually Minkowskian as a whole. STR would cover such a simplified universe, so we can refer to that example if you wish. But the real universe has gravity and such, making GR the applicable theory.

Who is foaming? A person defending broken theories or a person who has shown them to be broken? Our little thought experiment shows that in an expanding universe it would be possible to measure absolute speeds if you create clocks early on, send them out in different directions and then compare their times to see how they've ticked at different rates. That clearly would work if it had been done. Something like it can still be done now though: we don't need to go back to the big bang to do an experiment like it because any part of space that's expanding today will provide the same kind of opportunity, and that works in a universe with or without gravity in it. At a single locality, we can see that the same apparatus moving through that place at different speeds but otherwise set up identically from the point of view of the observer travelling with it must produce different results that would reveal a different absolute speeds of motion for the two sets of apparatus if that space is expanding. That's a radical breakthrough, and making radical breakthroughs of that kind is not foaming. Foaming is reserved for the people who resist the big advances when they're made.

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The scientist can only read the clocks once when they pass by him. And the accelerated ones will be behind, exactly as STR predicts.

Are you sure? We have a clock and a watch sitting near each other which the scientist look at and travel to and fro between them to confirm what they're doing: one of them has registered millions of years less time passing than the other, and other scientists looking at clocks and watches throughout the universe are finding the same thing and sending their findings to each other. The ones that were moving fast early on have slowed to a near halt now, but they still lag behind with their timings. As for which were accelerated, we can have the watches send out miniwatches in the same way and have set D of miniwatches accelerated until they are at rest with the clocks. When you compare the clocks with the watches, which ones are behind with their times and were accelerated. Let's say that the watches are behind with their timings because they were accelerated. When you compare that set of watches with one set of miniwatches though, which ones are behind with their times and were accelerated? STR can't handle that precisely because both these cases can happen in the same system, and if in the first case you have the watches recording less time than the clocks after being accelerated away from them, in the second case you will have the miniwatches record more time than the watches after being accelerated away from the watches: the accelerated ones end up ticking faster in this second case. That result is fully compatible with LET, but not with STR.

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Then suggest an empirical test in a universe without gravity and such that STR predicts incorrectly. Can’t do that?

That's precisely what I set out in my paper: a test which would show two identical sets of apparatus set up identically but with them moving relative to each other and where they produce different measurements due to their different absolute speeds of motion. Gravity or the lack of it wouldn't change the results. You can see from the other thought experiment that expanding space provides ways to pin down absolute speeds, and all I did was convert that approach to an experiment that could be done today without needing to set things up in the early days of the universe.

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But STR doesn’t make any philosophical assertions. It’s all empirical.

It absolutely does: it asserts that there's no absolute time and that absolute speeds of motion don't exist. But mathematics says otherwise, and so does our expanding universe. STR has always been bad philosophy dressed up as science.

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So you’re asserting physics is locally measurably different at different potentials? You’d notice time slowing? Seriously? How about at speed then?  If I move at .99c, will I notice everything moving slow? Just wondering where you stand on this.

What I'm saying is that nothing that's going on out there is incompatible with absolute time. It could be measured locally if you know how fast you're moving and how deep you are in the collective gravity wells that can influence the place where you are. You would never notice time slowing when time never slows: if you move at 0.99c you will have your functionality slowed down and you'll notice everything else happening fast (after adjusting for Doppler shift).

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You misunderstand. I’m talking about time as measured by clocks at Earth potential and a different potential (neither at zero potential) of the distant observer. Both are stationary relative to the comoving coordinate system. We’re both measuring the ‘absolute’ speed of some mutually visible object, and getting different numbers because our clocks (neither of which has ever accelerated) tick at different rates. Clearly speed is relative if we’re getting different answers. Where’s the absolute clock that measures the time it takes the object to go distance X?

There doesn't have to be an absolute clock to measure that. There only needs to be absolute time to govern it, and while absolute time can be referred to as a clock of a kind, that doesn't guarantee that anyone can ever read it or determine exactly how fast it ticks. But if you assume that the functionality of both your well-separated observers have clocks that are ticking at the same rate as each other due to their similarly low speed and similar depth in the local collective gravity wells (i.e. the ones in the universe detectable from there), they will not get different speed measurements for an object half way between them. For them to get different answers, they would either have to be moving at different absolute speeds (which they could measure by using my experiment) or they would be at different depths in gravity wells (which they could assess by measuring the amount of material affecting them gravitationally and the degree to which it is doing so). If they adjust for both of those, they should agree on the speed of the object. If you still have a difference in the measurements after that though, then something else must be slowing one of the observers, and that could potentially result from additional slowing depending on how fast the local space fabric is moving through some medium external to the universe.

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Without an absolute clock, the universe would fall apart through event-meshing failures in an instant.
I would just have said that absolute speeds are meaningless without such a clock, but if you want the universe to fall apart due to your assertions, who am I to argue?

If one object could take a shorter time-length path into the future than another, they would be incapable of meeting up again with different times on their clocks because when one arrives at the meeting point, the other would not be able to keep the appointment as it would be late in arriving there, even though it has to pass through that same spacetime location. That's not quite "falling apart", but it's a reasonable description of the result. The only way they can actually meet up again with different times on their clocks is if one of them has been ticking slow under the governance of absolute time.

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express it as a proportion of c.
Light doesn’t move at c in your absolute universe. It only moves at c at zero potential. This has been demonstrated. Relativity would say that it empirically moves at c ‘here’, using local rulers and clocks, but at least one of those is wrong in your interpretation.

As I've said before, there's absolute speed and there's absolute speed. It's the same with the speed of light: there's the speed of light and the speed of light, and they can differ because they're not the same thing. Where the "speed of light" is lower than the actual speed of light, "absolute speeds" will be higher than the actual absolute speeds. When you make a measurement of absolute speed using my experiment, you're using the "speed of light" and you're calculating "absolute speeds" accordingly. If you want absolute absolute speeds then you need to know what the absolute speed of light is and then adjust for that accordingly. What matters for the sake of this conversation is the speed of objects relative to the local speed of light, and once you have that, you can then measure the one-way speeds of light in different directions relative to the apparatus while always being fully aware that those are not the same thing as absolute absolute speeds. STR doesn't even allow for these "absolute speeds" that are proportions of the local speed of light, so you're just taking things off on an unnecessary diversion in an attempt to muddy the waters.

There are two key things that matter here. (1) If accelerated watches tick slower than unaccelerated clocks while accelerated miniwatches (that are comoving with clocks from moments after their creation having been accelerated and then decelerated a moment later) are ticking more quickly than watches, then STR is making incorrect predictions about the result either of the first acceleration or the second acceleration. (2) If two sets of identical apparatus set up the same way at the same location but moving at a different speeds don't produce a null result like the MMX, STR is making incorrect predictions, while if the local space is expanding, there cannot be a null result. Nitpicking about what exactly absolute speeds are is a sideshow: we have them regardless.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 30/05/2021 14:27:52
STR it denies the existence of absolute time and absolute speeds of motion

[STR] asserts that there's no absolute time and that absolute speeds of motion don't exist.
Where does it do that? Quote the 1905 paper please. That would indeed constitute a metaphysical claim. I don't see how that could be demonstrated from the premises.

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We have a clock and a watch sitting near each other which the scientist look at and travel to and fro between them to confirm what they're doing
Clocks not in each other’s presence cannot be unambiguously compared. If they’re near each other and millions of years apart, then either they were never in sync or the slow one has been accelerated towards the faster one and will eventually meet it, in which case said scientist would not need to travel between them. You seem to be making up wrong numbers. How did they get millions of years apart if they’re ‘near each other?’ Is one continuously accelerating back and forth or something?
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The ones that were moving fast early on have slowed to a near halt now
This language seems to assume absolute speeds. If you want to prove your interpretation, you can’t beg it up front. Only relative to this cosmological coordinate system do inertial things slow down over time, and I can assign such coordinates to any preferred event in spacetime, meaning that frame references are still necessary.
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When you compare that set of watches with one set of miniwatches though, which ones are behind with their times and were accelerated?
Acceleration is absolute. There is no question about which ones have done this.
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STR can't handle that precisely because both these cases can happen in the same system, and if in the first case you have the watches recording less time than the clocks after being accelerated away from them, in the second case you will have the miniwatches record more time than the watches after being accelerated away from the watches: the accelerated ones end up ticking faster in this second case. That result is fully compatible with LET, but not with STR.
Sorry, but I cannot parse what you’re trying to convey. It sounds like an empirical result claimed incompatible with STR, but I cannot follow it. What is a ‘same system’ as opposed to a different system? No systems were defined.

You have accelerated watches which at times pass by comoving clocks that have never been accelerated. The can be compared at this point and will be slow by time T. You then eject a miniwatch at each clock so it stays forever with the clock while the watch continues on. But the miniwatch will forever be slow by time T then relative to the clock in its presence.
That’s all I got from your description. STR doesn’t predict anything different, but I think there was more to it.
Please be specific about when things happen and what change of speed is done.
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That's precisely what I set out in my paper: a test which would show two identical sets of apparatus set up identically but with them moving relative to each other and where they produce different measurements due to their different absolute speeds of motion. Gravity or the lack of it wouldn't change the results.
I don’t remember the paper. I remember something about an experiment performed just outside the solar system, which will very much be affected by gravity, so you’re lying to yourself if you suggest otherwise. If the experiment is done in without gravity, then it need not be performed away from (nonexistent) mass. Anyway, I forgot how it went, but it seemed to be begging since frame references were missing. It assumed its conclusions. Maybe I remember incorrectly.

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What I'm saying is that nothing that's going on out there is incompatible with absolute time. It could be measured locally if you know how fast you're moving and how deep you are in the collective gravity wells that can influence the place where you are. You would never notice time slowing when time never slows: if you move at 0.99c you will have your functionality slowed down and you'll notice everything else happening fast (after adjusting for Doppler shift).
Pick a specific example then.  On Jan 1 (noon, absolute time, to which your watch is set), you jump towards a very large black hole (one large enough that tidal forces aren’t a bother even after 10 subjective minutes inside).  After one day (your watch, noon Jan 2), you cross the event horizon, noticing nothing different. At 10 minutes past noon (your watch), what absolute time is it?
I know I didn’t give all the specifics like the actual mass. Not looking for some fancy calculation.  I claim the question is unanswerable, and that makes it indeed incompatible with absolute time. Your hand-wave assertion to the contrary shows me only that you don’t have an answer.
Absolute time cannot be ‘measured locally’. Our falling guy has no defined speed or gravity depth. These things are not defined under your proposed coordinate system. He has exited your chosen coordinate system. That’s my point.

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There doesn't have to be an absolute clock to measure that. There only needs to be absolute time to govern it, and while absolute time can be referred to as a clock of a kind, that doesn't guarantee that anyone can ever read it or determine exactly how fast it ticks.
So just another thing that is there, but functionally inaccessible.
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clocks that are ticking at the same rate as each other due to their similarly low speed and similar depth in the local collective gravity wells
Gravity well depth is absolute. It isn’t a local thing. Speed differences aside, two clocks will tick in sync only if they’re at the same potential, not at the same ‘local’ potential. This is true even between clocks separated by far more than the size of the visible universe.
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or they would be at different depths in gravity wells (which they could assess by measuring the amount of material affecting them gravitationally and the degree to which it is doing so).
That was my point. At what point do you decide to cut this off? Very distant star X affects my gravitational potential, but star Y one AU further away does not. Seems fishy, especially since the distant objects contribute more to the potential than the nearby ones do.

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There are two key things that matter here. (1) If accelerated watches tick slower than unaccelerated clocks
Begging statement, meaningless under relativity. Try harder. Use empirical language. Don’t say what rates things tick. Say what will be measured at specific events.
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(2) If two sets of identical apparatus set up the same way at the same location but moving at a different speeds don't produce a null result like the MMX, STR is making incorrect predictions
Galilean PoR says both apparatus (each in motion relative to the other) will measure the same local thing. You’re weren’t real specific about what you want measured.
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while if the local space is expanding, there cannot be a null result.
And why does it take 20 posts to get the specifics of this non-null result? So far all I have is accelerated watches that are slow by exactly the amount predicted by relativity.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 31/05/2021 04:53:26
STR ... asserts that there's no absolute time and that absolute speeds of motion don't exist.
Where does it do that? Quote the 1905 paper please. That would indeed constitute a metaphysical claim. I don't see how that could be demonstrated from the premises.

Why restrict things to that specific paper when you know that Einstein insisted that there's no absolute time or absolute speeds of motion? You must know full well what the theory asserts. In that original paper, which at no point even refers to a theory of relativity, he was initially careful not to overstate the case, so in paragraph two of that paper he says, "Examples of this sort, together with the unsuccessful attempts to discover any motion of the earth relatively to the 'light medium,' suggest that the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest." ... "The introduction of a “luminiferous ether” will prove to be superfluous inasmuch as the view here to be developed will not require an “absolutely stationary space” provided with special properties, nor assign a velocity-vector to a point of the empty space in which electromagnetic processes take place."

Later on we have, "So we see that we cannot attach any absolute signification to the concept of simultaneity, but that two events which, viewed from a system of co-ordinates, are simultaneous, can no longer be looked upon as simultaneous events when envisaged from a system which is in motion relatively to that system."

All of these things became stated more strongly over time, leading to everyone in physics recognising that he was ruling out absolute time and absolute speeds. STR further evolved with Minkowski's input with the idea of spacetime, which leads to there being more than one STR model. But what was very clearly ruled out by Einstein was LET, because if it was merely LET, it wouldn't be Einstein's theory at all.

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We have a clock and a watch sitting near each other which the scientist look at and travel to and fro between them to confirm what they're doing
Clocks not in each other’s presence cannot be unambiguously compared. If they’re near each other and millions of years apart, then either they were never in sync or the slow one has been accelerated towards the faster one and will eventually meet it, in which case said scientist would not need to travel between them. You seem to be making up wrong numbers. How did they get millions of years apart if they’re ‘near each other?’ Is one continuously accelerating back and forth or something?

It's really quite simple. If there's a clock here and another one a thousand miles away over there, I can note the time on the clock here, then travel a thousand miles to look at the clock there, note down its time, then come back to the first clock and look at its time again and note that down. If the first time is 13.8 billion, the second time is 13.75 billion and the third time is 13.8 billion, then it's clear that the clock over there is behind the clock over here with its timing. The two clocks might even be sitting side by side though, eliminating the need to make trips between them.

If we're able to look at the clocks a minute after they're created though, a million years after the big bang, we can see that some of the clocks have registered a minute passing since they were created, while the watches that were sent out from them at 0.866c from them ten seconds after the clocks were created have only registered 35 seconds passing since they and the clocks were created, and we can see these passing each other to confirm that. Let's have cameras built into them which can photograph their clock and any watch that comes by to say hello when they give each other a high five (or twelve) - that will leave us with lasting photographs that document the action without us having to be there at all: photos showing after a year that when clocks pass watches the watches have only registered half a year passing while the clocks have registered a whole year. The expansion of space is so slight in that length of time that it barely slows the watches speed of travel in that time. And when some of the miniwatches that were sent out from the watches ten seconds after the watches were sent out from the clocks, well, lo and behold, the photos show some of them passing watches with a year recorded on their dials to the half year on the dials of the watches, and when clocks and miniwatches drift into close contact, they are both shown to have a year recorded on them. That's just one set of photos though. There will be others that show a clock meeting a watch where the watch has 20 years on it while the watch only has 10 years. And so on. You can fill in the rest using your own imagination.

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The ones that were moving fast early on have slowed to a near halt now
This language seems to assume absolute speeds. If you want to prove your interpretation, you can’t beg it up front. Only relative to this cosmological coordinate system do inertial things slow down over time, and I can assign such coordinates to any preferred event in spacetime, meaning that frame references are still necessary.

I assume nothing of the kind. It's about looking at the options as to what may be the case, and all options need to be covered. If the clocks are stationary and the watches are moving at 0.866c, then the watches will tick half as often as the clocks, but if the watches are stationary and the clocks are moving at 0.866c, then the watches will tick twice as often as the clocks, and if the clocks and watches are moving at the same speed as each other, then they will tick at the same rate as each other too. When you compare them as they pass each other, you will see those timing distances and will be able to tell a lot about what their absolute speeds must be (with the complication that you need to measure it in three dimensions and not just one, so you need to compare clocks passing each other in different directions to get the full picture.

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When you compare that set of watches with one set of miniwatches though, which ones are behind with their times and were accelerated?
Acceleration is absolute. There is no question about which ones have done this.

Both the watches and the miniwatches have accelerated, but the clocks haven't. And when we're considering the action that only involves the watches and miniwatches, only the miniwatches have accelerated. In the first case we have the watches accelerate away from the clocks and tick more slowly as a consequence. In the second case we have one set of miniwatches accelerate away from the watches and tick more quickly as a consequence. And we have conformation of this by the fact that when we compare neighbouring miniwatches and comoving clocks, they are ticking at the same rate as each other. So, if the watches were accelerated and ticked more slowly as a result, then the miniwatches were decelerated and ticked more quickly as a result. (The "if" and "then" in that are important because it could be that the watches were decelerated and the miniwatches were accelerated, but you'd see the difference between those two possibilities by comparing the times on watches and miniwatches when they pass each other. The ones with more time recorded on them must have been decelerated.

You say that I assumed absolute speeds, but these are dictated by the twins paradox: if you don't have absolute speeds, then accelerating the watches and decelerating the miniwatches won't change their ticking rates at all, so whenever any of these timers pass other timers they would all have to read the same time. Or, if you're relying on some kind of magic with the accelerations to govern the timings, then the deceleration of the miniwatches would have to be an acceleration too and they would be left ticking slower than the watches, which would lead to clocks and miniwatches sitting side by side with one ticking at four times the rate of the other.

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Sorry, but I cannot parse what you’re trying to convey. It sounds like an empirical result claimed incompatible with STR, but I cannot follow it. What is a ‘same system’ as opposed to a different system? No systems were defined.

The system is the universe in which these clocks are operating. Case 1 is what happens in relation to the clocks and watches. Case 2 is what happens in relation to the watches and miniwatches, but we're particularly interested in the miniwatches sent out in such a way that they end up sitting at rest relative to the nearby clocks. In case 1 we have accelerated watches which tick half as fast as the clocks after that acceleration. In case 2 we have accelerated miniwatches which tick twice as fast as the watches after their acceleration away from those watches. That means we have two cases of timers being accelerated which STR predicts will tick more slowly as a result of the acceleration, and yet in the second case the opposite happens: we instead see them behave in the way that LET predicts.

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But the miniwatch will forever be slow by time T then relative to the clock in its presence.

Given the ten-second delay between the two accelerations, we can ignore that tiny difference in the timings a year later, but yes, there will be a slight lag.

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That’s all I got from your description. STR doesn’t predict anything different, but I think there was more to it.
Please be specific about when things happen and what change of speed is done.

I was specific, but it takes time for people to take the details in with something like this and understand what's going on well enough to be able to recognise the point of it all. That's why it's so hard to get anywhere discussing this when 99.99% of people don't want to know what it reveals and would rather just say it's wrong without understanding it.

Normally when you run a twins paradox, you can't get a definitive answer as to which clock might be ticking faster than another clock that moves past it, but with expanding space we can because it enables us to separate clocks and know that any that are at rest, if there is such a thing as at rest, will display the same time on them when we bring them together, whereas if one is moving and another is at rest, then when we bring those together (with apparently identical accelerations), the one with the higher absolute speed will have recorded less time than the other. And if there are no absolute speeds, then none of them can have recorded different amounts of time passing because they were all created at the same time and none of them could be ticking slow, but the twins paradox bans that result because three of the clocks can pass each other in the manner, A passes B, B passes C, then C passes A, and if they were all ticking at the same rate then timing A (between clock A's encounters with B and C) will be equal to timings B plus C (their timings being the time between their encounters with the other two clocks), but the twins paradox demands that timing A > B+C, and as soon as you have A > B+C, you have either clock B or C ticking at a lower rate than clock A because of its higher absolute speed. In normal cases, you can't tell which clocks have higher or lower absolute speeds, but in this case with the expanding universe, you can: you can see it whenever clocks pass each other because they weren't separated by movement through space, but by expansion of space, and the latter does not affect their relative ticking rates, whereas the former does. I never start from the assumption that absolute speeds exist: their existence is forced by the twins paradox. People then deny that the twins paradox reveals that, even though it does, and they do this with the feeble excuse that you can't tell which clocks are moving faster or slower than which, but in these thought experiments with expanding space, you can tell that.

[post length limit, so only half way here...]
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 31/05/2021 04:54:31
[...2nd half]

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I don’t remember the paper. I remember something about an experiment performed just outside the solar system, which will very much be affected by gravity, so you’re lying to yourself if you suggest otherwise.

If you had actually read the paper carefully and understood it, you would know that gravity does not prevent it from producing good results. If you were to move the apparatus along at 0.866c (and I use this high speed just to illustrate the way it works by making the difference in measurements stark), the expansion of space between the two outer clocks would lead to light signals from them to the central clock taking extra time to reach the central clock, but that extra time taken would be getting on towards fifteen times longer from the trailing clock than from the lead clock, and that difference is not cancelled out by synchronisation differences in the way that happens at the start of the experiment before the space has expanded. (In the paper I actually switch though to not allowing the clocks to move apart, but to hold them at a fixed separation instead and to allow space to move through them as it expands - the trailing clock will then move through the extra space at a higher speed relative to it than the lead clock does, making it tick slower while they maintain their actual separation, but the end result is the same difference in the timings. The paper can be seen here: https://independent.academia.edu/DavidCooper173 (https://independent.academia.edu/DavidCooper173) - very few views registered there because I normally send people to a copy on my site instead as that only takes one click, but it's unreliable free hosting and has been unavailable a lot in recent days.)

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Pick a specific example then.  On Jan 1 (noon, absolute time, to which your watch is set), you jump towards a very large black hole (one large enough that tidal forces aren’t a bother even after 10 subjective minutes inside).

Hold it right there. LET predicts that the functionality of a clock halts at the event horizon, and if you could get the clock inside the black ball, it would be halted there too, so there is no such thing as 10 subjective minutes inside. LET agrees with GTR about all predicted measurements that can be accessed from outside the black hole, but they differ radically when it comes to what goes on inside.

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After one day (your watch, noon Jan 2), you cross the event horizon, noticing nothing different. At 10 minutes past noon (your watch), what absolute time is it?
My watch has been stopped for who knows how long, so it never reaches ten past noon, but absolute time has continued to run at the same constant rate for the whole universe and all its content.

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I know I didn’t give all the specifics like the actual mass. Not looking for some fancy calculation.  I claim the question is unanswerable, and that makes it indeed incompatible with absolute time. Your hand-wave assertion to the contrary shows me only that you don’t have an answer.

Your assertions are the result of you assuming that GTR is right, and its incompatibility with absolute time is just one of a number of symptoms of its brokenness. I do have an answer, and it's that a clock only goes on ticking inside a black hole in broken theories. But time continues to operate in there; it's just that any clock governed by the speed of light will be halted. Absolute time is not governed by the speed of light, but instead has a role in governing the speed of light.

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Absolute time cannot be ‘measured locally’. Our falling guy has no defined speed or gravity depth. These things are not defined under your proposed coordinate system. He has exited your chosen coordinate system. That’s my point.

He hasn't. He's descended to the event horizon and stopped there with his functionality frozen. He can only go inside the event horizon by more stuff falling on top of him and increasing the energy density there to make the event horizon migrate out past him, and still his is frozen motionless. He might stay there for trillions of years of absolute time before he is destroyed by the process that generates Hawking radiation. (Trillions is a guess - maybe it's quadrillions or quintillions, but I'll just stick with trillions for now even if its not enough.) Meanwhile, GTR has him continue down to a singularity instead and he stays there for an infinite amount of the time external to the black hole, even though he is actually destroyed by that Hawking radiation process within mere trillions of years of that time external to the black hole. He has at no time exited my proposed coordinate system: you are merely attributing your own warped one that doesn't add up onto me, but I don't allow that kind of magic in the model. He cannot travel infinitely far timewise into the future and also be destroyed here within mere trillions of years. That brokenness of GTR is a big hint that it's wrong.

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So just another thing that is there, but functionally inaccessible.

It's hard for anything to happen without it. It's one of nature's key fundamentals, just like space.

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Gravity well depth is absolute. It isn’t a local thing.

Of course its local: you wouldn't have clocks tick at different rates in a lab by being on shelves at different heights otherwise. One is at deeper total depth than the other in all the gravity wells affecting them. Different localities are frequently at different depths. (Some are obviously at the same depth as each other though.) The important point here is that one of the observers may live in a much more massive galaxy than the other observer and his clock will therefore be ticking slower than the other observer's, so he would have to adjust for that for both observers to agree on the speed of the mutually observed object half way between them.

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At what point do you decide to cut this off? Very distant star X affects my gravitational potential, but star Y one AU further away does not. Seems fishy, especially since the distant objects contribute more to the potential than the nearby ones do.

The very distant ones are going to affect both observers to almost the same extent, and while the local mass of stuff may make a lesser contribution, it can still be the main cause of a difference in the rate their respective clocks tick at, so they most need to cancel that part of it out in order to come close to agreeing on the speed of the observed object.

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There are two key things that matter here. (1) If accelerated watches tick slower than unaccelerated clocks
Begging statement, meaningless under relativity. Try harder. Use empirical language. Don’t say what rates things tick. Say what will be measured at specific events.

Not meaningless at all. I can't shackle it by describing it through the lens of broken theories that don't fit the case in point. In the thought experiment with the clocks being created near the time of the big bang, we see that accelerated watches are ticking slower than unaccelerated clocks because we can look at the photos that show their times when they encounter each other and show that the clocks have registered more time passing. Those photos are the measurements. In previous posts I had observers comparing them and they were making the measurements. The measurement all show the clocks ticking faster than the watches, unless they don't, in which case we're dealing with a case where the watches were decelerated rather than accelerated, or a case in which the timings match and the watches were first decelerated to zero speed and then accelerated. Three different cases, but in each case the comparisons of times will tell us a lot about their absolute speeds, and when we look at how the miniwatches behave too (sent out in two opposite directions from the watches), we are going to see differences in timings when some of these timers meet up: the twins paradox demands that, and so absolute speeds are revealed as existing in all three cases.

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(2) If two sets of identical apparatus set up the same way at the same location but moving at a different speeds don't produce a null result like the MMX, STR is making incorrect predictions
Galilean PoR says both apparatus (each in motion relative to the other) will measure the same local thing. You’re weren’t real specific about what you want measured.

It's all spelt out in the paper. What we're measuring is signals sent at the speed of light from the two end clocks to a central clock. The space expands between them, and the extra distance the signals have to travel will be covered at different speeds if the clocks are moving in their direction of alignment, leading to a timing difference. There is no timing difference at the start of the experiment due to one clock being ahead of the other in its timing if the clocks are moving along that line: they are synchronised at the start by a light signal being sent out to them from the central clock. The outer clocks then send signals back to the central clock which initially arrive simultaneously at the central clock, but as the space expands between the clocks, the signals go out of sync unless the clocks were initially at absolute rest. It's that simple. If the clocks aren't at rest, then the clocks must go out of sync due to that expansion. If they don't, there cannot be any expansion.

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And why does it take 20 posts to get the specifics of this non-null result? So far all I have is accelerated watches that are slow by exactly the amount predicted by relativity.

It shouldn't take 20 posts. You had it all two and a half months ago, but you didn't want to understand it back then, and you probably still don't. You appear to misunderstand almost every point on purpose as a stalling tactic.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 31/05/2021 15:31:23
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I remember something about an experiment performed just outside the solar system, which will very much be affected by gravity, so you’re lying to yourself if you suggest otherwise.
If you had actually read the paper carefully and understood it, you would know that gravity does not prevent it from producing good results.
OK, so you’re lying to yourself. Has anybody with any physics knowledge actually reviewed this? Do you dismiss any review that points out errors? For one, you seem to assume that gravity somehow just shuts off ‘outside the solar system’.
You put two relatively stationary objects in interstellar space, the local stars around it will usually tend to pull the two objects apart.  The galaxy as a whole will also accelerate them as it accelerates our solar system.  If the two objects are aligned radially with the galaxy, they’ll tend to move apart. If aligned axially, they’ll tend to move together, but probably a lesser effect than the nearby stars pulling them apart.  If they’re aligned tangentially, they’ll tend to rotate about each other.  This is all simple orbital mechanics, having nothing to do with relativity.
Trying to measure expansion within a bound object is like trying to do it by tracking the distance between a pair of buildings over time. Such motion has been measured, but it’s continental drift, not space expansion that explains it.

So let’s at least be reasonable and put this setup in deep space between galaxy clusters in a place with minimal gravity gradient. Otherwise the gravity effects will totally dwarf any claimed expansion effects.

The paper talks about putting two objects in space, relatively stationary. If they’re separated by some distance, then they’ll have different peculiar velocities.  If the near end has zero peculiar velocity, the far end will have a peculiar velocity in the direction of the near end. Space might expand past it, but that object will remain a fixed distance from the near end over time unless a force (gravity say) accelerates it.  So the two ends will remain a fixed separation indefinitely. Your paper seems to naively assume that expansion is a force that somehow accelerates things, like there’s some kind of drag with the aether or something. That nobody has pointed this out seems to indicate that nobody has actually reviewed the paper.

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If you were to move the apparatus along at 0.866c
No frame reference. If you’re not begging your conclusion, then a speed is meaningless without a reference.
I will assume a peculiar velocity of .866c, and I’ll take a guess that it is along the line separating the two ends, but that also isn’t specified. I shouldn’t have to assume all these things. You should specify them.
You should also put the objects much further apart like a megaparsec so these things I’m pointing out become more obvious. It’s a thought experiment, so don’t be afraid to scale it up to make it stark, as you say. If it was actually a valid thing, then we can work to scale it down to practical distances and super-high precision measurements.  At a megaparsec, you don’t need many significant digits, but you need more time.
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the expansion of space between the two outer clocks would lead to light signals from them to the central clock taking extra time to reach the central clock
That would be remarkable…  I deny this claim unless there are external forces involved accelerating things.
You’ve described clocks synced relative to their own inertial frame, and if that inertia is maintained (no acceleration), then the proper separation between the two ends will be maintained and the measurement taken in the middle will get signals simultaneously from either end.
You’re describing a local test in supposedly gravity-free conditions (which interstellar space isn’t).  The cosmological frame cannot be detected by a local test.

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Hold it right there. LET predicts that the functionality of a clock halts at the event horizon
That seems to be an awful mark against LET then. It’s like looking at a flat map of Earth (like google maps) and noting that Greenland appears larger than Brazil despite the fact that it’s about a quarter the size of Brazil. That’s just a coordinate difference, and there is a coordinate singularity that makes both poles infinitely distant, so they’re never shown on such a map. LET would seem to assert that the south pole therefore doesn’t exist, asserting a physical singularity to what is a mere abstract coordinate singularity.  In fact, one can go to the south pole and not be able to tell there’s anything special going on there. One can draw a map of it, but only by choosing a different coordinate system. LET on the other hand refuses the validity of any but the one coordinate system, and thus metaphorically denies the existence of the south pole.  Ditto with black holes. Local spacetime at the event horizon is perfectly Minkowskian, and thus physics goes on as normal, as evidenced by a simple choice of a different abstract coordinate system such as the local inertial one of the guy falling in, or something non-local like Kruskal–Szekeres coordinates.

So LET acknowledges and runs away from the problem with hands on the ears, whereas relativity has no trouble with it. Defeated by confusing the map for the territory. So sad.

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Of course [gravity well depth is] local
I’m saying that the difference in depth between two events is not frame dependent. Your comment comparing very distant events (say outside each other’s visible universe) seemed to suggest otherwise.

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Use empirical language. Don’t say what rates things tick. Say what will be measured at specific events.
In the thought experiment with the clocks being created near the time of the big bang, we see that accelerated watches are ticking slower than unaccelerated clocks because we can look at the photos that show their times when they encounter each other and show that the clocks have registered more time passing.
Much better. Clocks are being compared in each other’s presence. No mention of tick rates which require a frame reference. The photo seems hardly necessary. The measurement can be logged and emailed for later comparision. No actual scientist need be present.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 01/06/2021 01:39:39
If you had actually read the paper carefully and understood it, you would know that gravity does not prevent it from producing good results.
OK, so you’re lying to yourself. Has anybody with any physics knowledge actually reviewed this? Do you dismiss any review that points out errors? For one, you seem to assume that gravity somehow just shuts off ‘outside the solar system’.

If you imagine doing the experiment with two sets of the apparatus moving at high relativistic speed relative to each other, the impact of gravity on it is rendered utterly irrelevant. If you do it with a very low relative speed, you then do have to be careful to correct for the interference of gravity where one of the clocks may have spent more of its time at a lower depth in a gravity well than the other, but you can calculate those differences by knowing the distribution of the local massive bodies that cause that difference. Distant objects won't cause measurable differences.

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You put two relatively stationary objects in interstellar space, the local stars around it will usually tend to pull the two objects apart.

That's discussed in the paper, and that's precisely why after setting out a version of the experiment in which the clocks are left free to move apart (to show people the principle of how it works), I then set out a preferred version where the clocks positions are controlled to prevent them moving apart. If one of them is deeper in a local gravity well than the other during some part of the experiment, the can be corrected for, but you'd obviously plan the positioning of the experiment carefully to try to make it equal on average.

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... This is all simple orbital mechanics, having nothing to do with relativity.

And it's all predictable stuff that we can correct for.

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Trying to measure expansion within a bound object is like trying to do it by tracking the distance between a pair of buildings over time. Such motion has been measured, but it’s continental drift, not space expansion that explains it.


It doesn't matter whether you call it a bound object or not. If the space is expanding between the two clocks and we are actively maintaining the distance between them, we are moving them through the amount of new space that has appeared between them, and that affects their timings. It also affects their timings differently if the central clock isn't at rest, and with a bigger difference in how much it affects their timings the further from being at rest the central clock is.

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So let’s at least be reasonable and put this setup in deep space between galaxy clusters in a place with minimal gravity gradient. Otherwise the gravity effects will totally dwarf any claimed expansion effects.

Ideally that's what we would do, but it could take millions of years to get it there. We don't need to wait that long though because we can correct for gravity well depth differences as they are predictable, so we can actually do the experiment on our own doorstep.

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The paper talks about putting two objects in space, relatively stationary. If they’re separated by some distance, then they’ll have different peculiar velocities.  If the near end has zero peculiar velocity, the far end will have a peculiar velocity in the direction of the near end. Space might expand past it, but that object will remain a fixed distance from the near end over time unless a force (gravity say) accelerates it.  So the two ends will remain a fixed separation indefinitely. Your paper seems to naively assume that expansion is a force that somehow accelerates things, like there’s some kind of drag with the aether or something. That nobody has pointed this out seems to indicate that nobody has actually reviewed the paper.

If the central clock is at rest, both the outer clocks will be moving through space in order to maintain their distance to the central clock, as you recognise - this must happen in expanding space. There is no force acting on the outer clocks unless we apply one to keep them at the right separation if they drift away from that, but if we get their speeds just right at the start, they'll hold station automatically, so the only corrections will be to deal with gravity's interference. What will cause the clocks to run slow in this case is their speed through space which is not zero if it is zero for the central clock. That equality in the slowing for the outer clocks will result in a null result for that set of apparatus. But we always do the experiment with two sets of apparatus. The other set has the central clock moving through space. One of the outer clocks may be at rest in space this time, in which case the other outer clock will be moving through space twice as fast as the middle clock. That would lead to a clear loss of synchronisation between the outer clocks, leading to a non-null result.

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If you were to move the apparatus along at 0.866c
No frame reference. If you’re not begging your conclusion, then a speed is meaningless without a reference.

It has a very clear meaning in LET and we're talking about measuring absolute speeds, so you shouldn't have any difficulty understanding what it means. The difference in results for the two sets of apparatus that you have to get in expanding space shows that absolute speeds are involved. STR says that they don't exist, so it requires a null result from both sets of apparatus, and in doing so it violates the rules of the twins paradox, as is spelt out in the paper.

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I will assume a peculiar velocity of .866c, and I’ll take a guess that it is along the line separating the two ends, but that also isn’t specified.

The direction is clearly specified as being along the straight line connecting the clocks.

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I shouldn’t have to assume all these things. You should specify them.

Indeed you shouldn't have to assume them: they are all spelt out clearly in the paper.

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You should also put the objects much further apart like a megaparsec so these things I’m pointing out become more obvious.

The paper describes an experiment that could practically be carried out during this century - that is why the distances were made small. If you want to make it bigger, that's an easy thing to translate to.

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the expansion of space between the two outer clocks would lead to light signals from them to the central clock taking extra time to reach the central clock
That would be remarkable…  I deny this claim unless there are external forces involved accelerating things.

The slowing of clocks isn't about accelerations, but about absolute speeds through space. The twins paradox carried out by three clocks that never accelerate demonstrate that. In the experiment we either have the outer clocks moving at the same speed as each other through space (in opposite directions) while the central clock is at rest, or we have one of the outer clocks moving through space faster than the other. It's a very low speed difference, but it all adds up to a timing difference.

You can understand that easily enough when you think about how when you try to separate two clocks very slowly, you end up with the same synchronisation as if you separated them very quickly to the same distance apart. No matter how slowly you move them, you get the same end result, but if you move the clock slowly, you have to move it for a lot longer.

Now, transfer that understanding to the experiment: we have two clocks moving at speeds through space that may only be a little different, but they move through space at different speeds for the same length of time as each other with one of them moving through more space than the other. That leads to a change in their synchronisation.

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You’ve described clocks synced relative to their own inertial frame, and if that inertia is maintained (no acceleration), then the proper separation between the two ends will be maintained and the measurement taken in the middle will get signals simultaneously from either end.

The synchronisation is only maintained if the central clock is at rest. If it is moving, one of the outer clocks will be slowed more than the other because it will be moving faster through space. The synchronisation will be skewed, of course, if the central clock is moving (along the straight line connecting the clocks), but it will initially look perfect in the frame in which the central clock is at rest. As time passes though, one of the outer clocks lags further and further behind the other, and the signals coming back to the central clock from the outer clocks will go out of sync with each other.

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You’re describing a local test in supposedly gravity-free conditions (which interstellar space isn’t).  The cosmological frame cannot be detected by a local test.

But it can be. We can calculate the impact of gravity and adjust for it, working out how much slower one clock would be ticking than the other based on their relative depth in local gravity wells so that we aren't misled by that aspect of the result.

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Hold it right there. LET predicts that the functionality of a clock halts at the event horizon
That seems to be an awful mark against LET then.

Quite the reverse.

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It’s like looking at a flat map of Earth (like google maps) and noting that Greenland appears larger than Brazil despite the fact that it’s about a quarter the size of Brazil...

No. It's like looking at a globe and seeing that the speed of light reaches zero at the event horizon while everything from there on down is functionally frozen: a black ball of stuff like the fuzzballs of string theory.

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Local spacetime at the event horizon is perfectly Minkowskian, and thus physics goes on as normal, as evidenced by a simple choice of a different abstract coordinate system such as the local inertial one of the guy falling in, or something non-local like Kruskal–Szekeres coordinates.

Spacetime is just a contrived abstraction. LET uses a Euclidean metric with the speed of light reducing in gravity wells, and that leads to it making the same predictions about things we can measure as GTR, but different ones about ones that we can't measure inside black holes. What shows us that LET is a more trustworthy account is the way that GTR has things travel down to a singularity where they run straight on into an infinitely far off future without delay, only to be destroyed in the near future of now (mere trillions of years rather than infinitely far beyond that) by the process that evaporates black holes and produces Hawking radiation. The problems you keep coming up with are all the product of applying a broken theory and seeing everything through its cracked lens.

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So LET acknowledges and runs away from the problem with hands on the ears, whereas relativity has no trouble with it. Defeated by confusing the map for the territory. So sad.

What would be sad would be if it pandered to the broken predictions of GTR which can't handle time properly. Instead of that, it sets out how things could more rationally function.

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I’m saying that the difference in depth between two events is not frame dependent. Your comment comparing very distant events (say outside each other’s visible universe) seemed to suggest otherwise.

I had no intention of suggesting otherwise.

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Much better. Clocks are being compared in each other’s presence. No mention of tick rates which require a frame reference. The photo seems hardly necessary. The measurement can be logged and emailed for later comparision. No actual scientist need be present.

Indeed. There are multiple valid ways of doing it.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 02/06/2021 04:10:19
It would really help if you actually put some numbers to what you expect to happen. I know numbers are not your thing, but the language of physics is mathematics, and you haven’t proposed anything if you haven’t worked out what you think will happen. I’m left guessing as to your guesses because you’re speaking the wrong language. The paper has almost no computations.
I see 100 au expanding by 50m in a month. That’s an actual computation. Care to show how you got 50m? I got about twice that.  Are you asserting that the relatively stationary objects are going to move apart 50m in a month?  I might agree with that only because the pull of the nearby stars might do that. Absent gravity and such, they stay 100 au apart relative to the inertial frame in which they were initially stationary, all per Newton’s first law of motion, which still applies.

Anyway, I can run your assertion to a contradiction if that’s the setup. Make sure you specify which coordinate system you are using because the paper switches back and forth between peculiar (what you call absolute) velocities and ‘frames A - H’ which I presume are inertial frames, but you don’t say that. It’s important, because you are working with inertial and non-inertial frames and you seem to treat them the same. You have things relatively moving when you assert them to be relatively stationary, a contradiction with inertial frames.
If the space is expanding between the two clocks and we are actively maintaining the distance between them, we are moving them through the amount of new space that has appeared between them, and that affects their timings.
You're trying to measure the slowing of a clock due to nearly zero peculiar velocity? First of all, it won't work, and second of all, I don't think 40 digits of precision would be enough if it was valid. You’re mixing inertial and non-inertial frames to get this conclusion. It’s wrong. You synced the clocks in an inertial frame, so the clocks will stay synced relative to that frame. They were never in sync relative to the cosmological frame in which the expansion takes place, but you seem to assume that they are.
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Ideally that's what we would do, but it could take millions of years to get it there.
Who cares? It only has to be possible. Being practical is only a goal if you expect anyone to actually do this. It’s a forum post, not a grant application. The experiment can take as long as you like as well. The reasons that it doesn’t work become far more apparent if you put your objects say a billion parsecs apart. Keeping it small only means all the instruments need to have 30 digits of precision instead of 2.

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If the central clock is at rest, both the outer clocks will be moving through space
Only in the cosmological coordinate system, which isn’t an inertial one.
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There is no force acting on the outer clocks unless we apply one to keep them at the right separation if they drift away from that
We’re doing this without gravity or dark energy, so they won’t drift. You seem to not so much be interested in keeping them relatively stationary as much as computing their time dilation due to their peculiar motion? But your clocks were never synced in that coordinate system, so no comparison can be made. All clocks will stay in sync forever in the inertial frame in which all of them are stationary.
As I said, it becomes more obvious if you scale up the thing much more than just 100 AU.
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What will cause the clocks to run slow in this case is their speed through space which is not zero if it is zero for the central clock.
Oops! To measure that, you’d have to sync the clocks relative to the cosmological frame, and you haven’t done that.
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[.866c, no reference] has a very clear meaning in LET and we're talking about measuring absolute speeds, so you shouldn't have any difficulty understanding what it means.
Fine. .866c peculiar velocity, which I already said I assumed.  That has meaning. Dropping the reference is begging your conclusion. I don’t accept LET, so I’m not going to accept a conclusion that is assumed in the description of the setup.
The experiment will behave the same. All clocks will stay in sync relative to the interial frame in which all clocks are stationary. Even LET does not suggest otherwise. It make the exact same empirical predictions (except for the experience of crossing into a black hole apparently).
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The difference in results for the two sets of apparatus that you have to get in expanding space
There is no difference unless external forces are involved, changing the proper separation of the objects. Any other result would falsify LET for one thing.
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Indeed you shouldn't have to assume them: they are all spelt out clearly in the paper.
Forgive me for not pouring over the details in the paper. It’s wrong right out of the gate, so I didn’t see all the details. I shouldn’t have said that such things needed to be spelt out when I hadn’t checked if they were.
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the expansion of space between the two outer clocks would lead to light signals from them to the central clock taking extra time to reach the central clock
That would be remarkable…  I deny this claim unless there are external forces involved accelerating things.
The slowing of clocks isn't about accelerations, but about absolute speeds through space.[/quote]Fine, but you’re not measuring the absolute time of the signals with your setup. You’re measuring the time relative to the inertial frame in which you synced all the clocks. The signal travel time will remain fixed for all eternity relative to that frame.
You have to change the setup if you want to measure the time relative to the cosmological frame, but then it’s relative to that frame, not absolute. Hence I don’t accept that the cosmological frame is absolute. I can create other such frames that behave exactly the same (with the primary clocks ejecting A and B watches and all that). It’s simply a coordinate system relative to an event rather than relative to an inertial frame. Of course the cosmological frame is still unique (preferred if you will) since there is but one obvious objective event in the universe, and it is relative to that event.
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think about how when you try to separate two clocks very slowly, you end up with the same synchronisation as if you separated them very quickly to the same distance apart.
Umm… no. You yourself say that it’s all about speed. Doing it fast results in a sync different from a slow transport. Neither method is a valid synchronization method. There are ways to do it. If you wanted to sync a pair of clocks relative to your ‘absolute’ frame, how would you do it? Assume both have known zero peculiar velocity, but it should also be possible between any set of clocks all with the same peculiar speed.
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Now, transfer that understanding to the experiment: we have two clocks moving at speeds through space that may only be a little different, but they move through space at different speeds for the same length of time as each other with one of them moving through more space than the other. That leads to a change in their synchronisation.
No it doesn’t, since they were not synced ‘with space’. They will maintain the synchronization which they were initially given.
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Spacetime is just a contrived abstraction.
Then LET apparently gives physical meaning to a contrived coordinate abstraction if it denies reality beyond said contrived abstraction.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 03/06/2021 05:38:48
It would really help if you actually put some numbers to what you expect to happen.

I thought the paper contained all the numbers it needs, but there are actually big mistakes in it which I would have found if I'd just worked out more numbers. The result is that a new paper needs to be written, but there was never any danger of this approach failing: the results merely show up differently from the way I'd previously thought. More on that below.

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I see 100 au expanding by 50m in a month. That’s an actual computation. Care to show how you got 50m? I got about twice that.

I got 100m too, which means each one has an additional 50m to send it signal back across to the central clock in the case where we don't maintain the separations, but it isn't 50:50 for all speeds, and that's where I made one of the big mistakes.

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Are you asserting that the relatively stationary objects are going to move apart 50m in a month?  I might agree with that only because the pull of the nearby stars might do that. Absent gravity and such, they stay 100 au apart relative to the inertial frame in which they were initially stationary, all per Newton’s first law of motion, which still applies.

Even without any gravity acting on them from anywhere, you can either have them move apart as the space between them expands or you can have them maintain separation simply by setting up their initial speeds differently. I introduced the idea by having them moving in order to help people understand how there is an effect to measure, but I then switched to maintaining the original distance between them so that the extra space being generated between them pushes extra space through them instead. That removed all the problems that the original idea suffered from. We then have a system in which if there's no expansion, all three clocks will remain in sync throughout the entire duration of the experiment, but if the space is expanding and the central clock is at rest, the two outer clocks will still remain in sync with each other throughout the experiment but will both lag behind the middle clock, and the amount by which they lag behind will be the same time that it takes for light to travel 50m. We know that because that's how much a clock will lag by if you move it 50m regardless of the speed you move it across those 50m. Light travels 50m in 167 millionths of a second (which is 167 ticks of a 1GHz processor) and is easy to measure: so easy, indeed, that we likely could reduce the separation to an astronomical unit, but let's just stick with 100 au for now.

If the space is expanding and the clocks are moving along through space such that one of the outer clocks is actually stationary, then the middle clock is going to move along through 50m of space and be 16.7 billionths of a second behind in its timing by the end of a month, while the other outer clock will have moved along though 100m of space and will be twice as far behind with its timing by the end of that month. The original synchronisation will have been skewed of course to fit the chosen speed of travel of the middle clock, because the synchronisation signal from the central clock will have reached the tail clock before the lead clock, but at that time, signals pinged straight back would still have reached the central clock simultaneously. After a month though, that will no longer happen: the signal from the tail clock will return 167 millionths of a second early and the signal from the lead clock will return 167 millionths of a second late, as measured by the central clock, so we have a clear measurable difference.

What happens if we move the clocks faster through space? Let's have the tailing clock move 50m through space over the course of the month while the middle clock moves 100m and the lead clock moves 150m. We now have the same difference in synchronisation as we had in the previous case, so we can't measure the speed difference between the two in the way I originally thought we could: we merely know that the clocks are moving in the same direction as before. So, it turns out that we can't work out their absolute speed from any running of the experiment unless its done in the range of transition where the clocks are nearly at rest. I need to write a new paper to describe this properly. What actually happens then is that we have a constant delay for a wide range of speeds on either side of being at rest, but with the opposite direction of delay for each of those sides. In between we have a rapid transition from a delay one way to a delay the opposite way. That makes it possible to pin down absolute rest with far higher precision than I previously thought could be achieved, and the changeover point would be a clear signal regardless of any gravitational interference, so you wouldn't even have to compensate for that. The downside is that it would take more runs of the experiment to find that zone of changeover. Initially, we would merely find out our direction of travel, and then we'd have to send the apparatus the opposite way at faster and faster speeds each time until we get the signal to reverse.

This is precisely why I wanted to run the paper past you before publishing it, but you weren't interested last time, so I had to publish it in a hurry due to things I'd already put out there about the case involving clocks being made near the time of the big bang which provided an opportunity for someone else to get in first with an experiment that can be done for real. I needed someone like you to push me into debugging it properly, and now that's finally happening, so it'll lead to a better second paper. If I sent my ideas to a journal in the normal way, there would be an opportunity to discuss and correct it before publication, but I can't go down that route as something this big would be stolen in a flash and have someone else's name put on it, so I have to publish directly every time, and having done that, it's no longer within their rules for it to be submitted to them. Now with this new finding, the first place that this latest bit has been published is right here on this forum. I will immediately put it up elsewhere afterwards too though as I like to get multiple time and date stamps on everything.

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We’re doing this without gravity or dark energy, so they won’t drift.

Of course they'll drift. If you have the central clock at rest while the outer two are maintaining distance from it with the space expanding in between, those outer clocks have to be moving through space while the middle clock is not moving through any, so they must tick slower than it. If they don't fall behind, they would then have to be moving through space at the same speed as the central clock, but that would mean there could not be any expansion of the space between them.

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You seem to not so much be interested in keeping them relatively stationary as much as computing their time dilation due to their peculiar motion? But your clocks were never synced in that coordinate system, so no comparison can be made. All clocks will stay in sync forever in the inertial frame in which all of them are stationary.

The whole point is that they can't all be stationary because of the expansion of space: they have to be moving at different speeds through the expanding space in order to maintain their separation distances, and clearly that's going to show. I imagined incorrectly before how the space was moving through them when they're moving at high speeds, and that made me think you'd get a bigger and bigger change in synchronisation between them the faster you move the apparatus through space, but no: I now think it's constant, except where it makes the transition from going one way to the opposite way, and at that point there's a massive signal in the change in direction of the lag when the tail clock switches over to being the lead clock. So, what you actually want to do is run the experiment to find out what the lag is, and that tells you the direction the clocks are moving in. You then slow it down by decelerating the system in the direction of the tail clock, and you just keep on doing so repeatedly. Once it reaches the point where the lead clock is at rest, the direction of the lag will change, reversing after the middle clock is at rest.

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To measure that, you’d have to sync the clocks relative to the cosmological frame, and you haven’t done that.

You don't. All you do is send out a signal from the central clock to the outer ones, and then they send signals back to the central clock many times. You keep sending signals both ways, of course, to maintain the same separation between them, but you don't keep correcting the main clocks: you just let them drift and look at the lags in the arrival of their specific signals.

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The experiment will behave the same. All clocks will stay in sync relative to the interial frame in which all clocks are stationary. Even LET does not suggest otherwise. It make the exact same empirical predictions (except for the experience of crossing into a black hole apparently).

No: LET predicts that the clocks are moving through space at different speeds and that they will tick at different rates as a result. STR predicts that they are all moving at the same speed relative to each other and that they will all tick at the same rate. That opens the way to test the theories by experiment and either disprove STR in expanding space, or disprove the idea that the space there is expanding, which would be devastating a much more important theory. If the space is expanding, you necessarily have a different speed of light relative to the lead clock than the tail clock in both directions along the line, and that is why STR cannot handle this case correctly. If you make the experiment big with the lead clock in one distant galaxy and the tail clock in another as far away from us in the opposite direction, then both of them are hurtling through those galaxies at relativistic speeds to maintain their distance to us, and yet we know that those galaxies are approximately at rest in their local space.

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The slowing of clocks isn't about accelerations, but about absolute speeds through space.
Fine, but you’re not measuring the absolute time of the signals with your setup. You’re measuring the time relative to the inertial frame in which you synced all the clocks. The signal travel time will remain fixed for all eternity relative to that frame.

The travel time for the signals does indeed remain constant, but when the tail clock is moving through space at a lower speed than the lead clock, the lead clock sends those signals out with a longer and longer delay each time, so they arrive late.

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think about how when you try to separate two clocks very slowly, you end up with the same synchronisation as if you separated them very quickly to the same distance apart.
Umm… no. You yourself say that it’s all about speed. Doing it fast results in a sync different from a slow transport. Neither method is a valid synchronization method.

Of course it's valid. One method of synchronising clocks is to send out simultaneously pulses of light to two clocks in opposite directions from half way between them, and they set themselves to zero when the signals arrive. If instead, from the same starting point, you send two synchronised watches out with one covering the distance to one clock in an hour and the other taking a day to get to the other clock, and then when those transferred watches read a particular time you set the two destination clocks to zero, you have sychronised them for the same frame as before. The speed at which you move a clock through space does not lead to a different synchronisation for the target clocks. Moving a clock delays it, and the delay that you get is the same size for a given distance of movement, and that delay is identical to the amount of time light takes to cross that distance. So, the delay to a clock from having space pass through it is the same as the time it takes for light to travel through that space.

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Spacetime is just a contrived abstraction.
Then LET apparently gives physical meaning to a contrived coordinate abstraction if it denies reality beyond said contrived abstraction.

Spacetime is a contrived abstraction of something else that fits reality more accurately, and LET describes that reality more accurately by not making irrational predictions about what goes on inside black holes: that's where the predictions between GTR and LET diverge. But at the moment we're dealing with a place where the predictions of STR and LET diverge, so exploring that is the priority for the moment.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 03/06/2021 17:12:45
I then switched to maintaining the original distance between them so that the extra space being generated between them pushes extra space through them instead. That removed all the problems that the original idea suffered from. We then have a system in which if there's no expansion, all three clocks will remain in sync throughout the entire duration of the experiment, but if the space is expanding and the central clock is at rest, the two outer clocks will still remain in sync with each other throughout the experiment but will both lag behind the middle clock
But they won’t lag, for the reasons I repeatedly pointed out, and that you will not see because you’re too busy knowing that you’re right.
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and the amount by which they lag behind will be the same time that it takes for light to travel 50m.
That is even more wrong. If the clocks had been synced relative to what you call the absolute frame, the lag will be a month of time dilation from the blistering motion of a millimeter per minute. I don’t have a calculator with enough digits to express that. Irrelevant because the clocks were not synced that way, so they’ll not lag at all.
Say Earth is stationary. The ISS moves relative to Earth about 660000 km (about 2.2 light seconds) each day. According to you a clock on the ISS would run 2.2 seconds slow per day instead of the actual figure of about 26 microseconds.
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This is precisely why I wanted to run the paper past you before publishing it
It is hard to review because you don’t have any mathematics in it. None of what I’m pointing out above is in the paper. Nowhere do you mention something like 167 milliseconds.
This is why I wanted numbers because I could have shown all this ages ago. It is difficult to critique a paper which doesn’t spell out what numbers are expected.
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an opportunity for someone else to get in first
Time is not of the essence. Nobody is racing to find this, since it doesn’t demonstrate anything. Both interpretations predict the exact same numbers. If you don’t get identical numbers, you’re making a mistake. Thus there is no conclusion since there’s no distinct results from one interpretation or the other.
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We’re doing this without gravity or dark energy, so they won’t drift.
Of course they'll drift.
Yes, they will, because the real universe has gravity. A thing in orbit cannot be inertial. I cannot think of an object in the universe that isn’t accelerating all the time relative to any coordinate system you can think of except its own proper local frame, and even then…
This is why I’m concentrating on the gravity-free hypothetical case. A test that doesn’t work in the ideal case doesn’t need to worry about being made practical.
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You seem to not so much be interested in keeping them relatively stationary as much as computing their time dilation due to their peculiar motion? But your clocks were never synced in that coordinate system, so no comparison can be made. All clocks will stay in sync forever in the inertial frame in which all of them are stationary.
The whole point is that they can't all be stationary because of the expansion of space: they have to be moving at different speeds through the expanding space in order to maintain their separation distances, and clearly that's going to show.
This is what I mean. I tell you what’s wrong, and you don’t hear it. Actually read what I say and don’t just assume I’m wrong.
You didn’t sync your clocks ‘with space’, so it doesn’t show what you’re trying to show. If you did sync them that way (no proposed method to do this is mentioned in the paper, which is probably good since clocks ticking at different rates cannot be meaningfully synced), then indeed, relative to that non-inertial coordinate system, the moving ones will lag (by a number far to small to measure by current technology) and this lag is exactly predicted by relativity as well, so it doesn’t falsify either interpretation.
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All you do is send out a signal from the central clock to the outer ones, and then they send signals back to the central clock many times. You keep sending signals both ways, of course, to maintain the same separation between them
Sending signals does not help maintain separation. If they’re stationary relative to some inertial frame, they’ll stay that way. Unclear what all these repeated signals do. One signal sent from the central place is enough to sync (to set to zero say) the outer ones with each other.  After that, any subsequent signals will be received by the center in exact normal rate with no additional lag at all, even under your interpretation. You seem entirely unaware of this.
Even in your interpretation, if the central clock is ‘stationary’ and the outer ones are moving inward slowly to maintain constant proper distance, the signals from the outer clocks (sent every local second say) will arrive at the central clock every second, exactly. The 3 clocks are not in (absolute) sync with each other, but that doesn’t change the rate at which the central clock will receive the signals.
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No: LET predicts that the clocks are moving through space at different speeds and that they will tick at different rates as a result.
That’s a metaphysical assertion, not an empirical prediction. LET does not make different empirical predictions (again, apparently excepting the black hole thing, which is sort of like religion making a different empirical prediction about the afterlife: The experiment can be performed, but the observer is safely prevented from reporting his findings to the rest of us).
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STR predicts that they are all moving at the same speed relative to each other and that they will all tick at the same rate.
STR makes no such metaphysical assertions, and you’ve declined to provide a reference where it does. STR only predicts what will be measured at specific events. Do you understand the difference? Your experiment can only be based on measurements, not on assertions. You can’t directly measure the separation between two things because you can’t be at both ends at once, so be very specific about how you’re going to know the separation of things and which coordinate system is used to express the result.
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The travel time for the signals does indeed remain constant
Have you computed that or is this just another guess? This would be come far more apparent if you scaled it up to gigaparsecs instead of 7 light hours. Don’t guess.
You set it up with constant proper separation of the clocks relative to an inertial frame so say the clocks are held separated with a 100 AU rigid stick.  Using the cosmological coordinate system, the distance between clocks is always shorter than 50 AU due to length contraction of the moving ends. The proper separation of those clocks is increasing due to that motion slowing down over time.

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think about how when you try to separate two clocks very slowly, you end up with the same synchronisation as if you separated them very quickly to the same distance apart.
Doing it fast results in a sync different from a slow transport. .
If instead, from the same starting point [equidistant between two end points], you send two synchronised watches out with one covering the distance to one clock in an hour and the other taking a day to get to the other clock, and then when those transferred watches read a particular time you set the two destination clocks to zero, you have sychronised them for the same frame as before.
This is nonsense even in your interpretation, which is apparently the one you’re using due to the lack of frame references. The watch spending an hour at speed is going to be behind the one that did the same distance in a day.  Say the separation is .95 light hours each way. Both watches are zeroed and sent out at midnight. The fast watch moves at .95c, gets there at 1AM and reads 12:18:45 which is 41:15 behind. The slow watch goes the same .95 LH distance in a day at .0396c and reads 11:58:52 PM which is 1:08 behind. That’s over 40 minutes out of sync. I think you need to review the basics. Everything of yours seems to be based on guesses. Run the numbers. Your reaction to all my posts seems to be a knee-jerk reaction to disagree with everything rather than to actually consider the possibility that your guesses are wrong.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 04/06/2021 01:46:43
But they won’t lag, for the reasons I repeatedly pointed out, and that you will not see because you’re too busy knowing that you’re right.

They'll only fail to lag if the space isn't expanding. You cannot have one clock at rest in space while the other two are moving through space with all their clocks ticking at the same rate. You asked me to go big with this and I did: I gave you an example with the two end clocks in distant galaxies on opposite sides of the sky from us while the central clock is here. To maintain the same separation, those distant clocks have to travel through those galaxies at relativistic speed. Clocks at rest in those galaxies are ticking at about the same rate as our clock here, but the distant clocks that are hurtling through those galaxies to maintain a constant distance from us can't tick at that same rate as those local clocks at rest without destroying the twins paradox locally where they are.

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If the clocks had been synced relative to what you call the absolute frame, the lag will be a month of time dilation from the blistering motion of a millimeter per minute.

Why are you trying to synchronise them by any frame other than the one in which the central clock is at rest? Not that it actually matters though as all we need is a measure in the change in the synchronisation over a month, so any initial synchronisation at all would actually do. I had misremembered how slow clock transport works though, so you're right about that part of the problem: the separation between the clocks needs to be much bigger to get a significant speed difference through space for them, and that makes the experiment much harder to do, so again your help in debugging this has been invaluable.

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Both interpretations predict the exact same numbers. If you don’t get identical numbers, you’re making a mistake.

They don't. When you put the outer clocks in distant galaxies you can see that: they must tick much more slowly than the central clock. We're now back to having a smooth change in the lag for the absolute speed of travel of the apparatus rather than a distinct signal as you do it within close range of it being at rest, so there's no sudden clear signal of the kind I imagined last night. But the principle remains right: the two theories do not predict the same numbers. Clearly the experiment may be a lot harder to do than I'd hoped, though, we have much more accurate atomic clocks now than we used to, so what do the numbers say about that:-

With an aeroplane moving at 500 mph we have a loss of 3 millionths of a second per month. (I found that at the bottom of this page http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/airtim.html (http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/airtim.html) where it gives the difference over 48 hours.) With our clocks 100 au apart we have roughly 60 mm per hour of speed difference, so that's a long way short: we'd need the clocks to be a trillion au apart for the same size of signal. However, we have much more accurate clocks available than at the time of Hafele Keating: our best atomic clocks can now measure ticks as small as 10^(minus19) seconds, or a tenth of a billionth of a billionth of a second. That's a tenth of a millionth of a trillionth, so we have ten trillion times as much accuracy as is needed to detect the loss of 3 millionths of a second in a month with a 500mph speed. That should allow us to bring the trillion astronomical units down a fair chunk, but I don't know how much? I can't get my calculator to make a prediction for the 500mph case as it runs out of precision along the way, so that makes it difficult to work with any lower speeds than that.

Edit: I've found a workaround for that. The speed 0.1c leads to a clock ticking 0.995 as often as a clock at rest. Try it again with 0.01c and you get 0.99995, so you just stick a couple of extra nines in there. Try it again with 0.001c  and you get 0.9999995, so again you just stick another pair of nines in, and that pattern goes on repeating. So, for every division of the speed by ten, we need a hundred times more resolution with the timers. That means that our ten trillion times (13 zeros in there) more precision than is needed for 500mph = 220m/s =  220000mm/s, we can get rid of at least six of those zeros, taking us down to under 2mm/s. It wouldn't surprise me if there's a big error in there somewhere, but I'm up late and I'm too tired to check it again right now.

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A thing in orbit cannot be inertial.

We don't allow the clocks to follow orbital paths.

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You seem to not so much be interested in keeping them relatively stationary as much as computing their time dilation due to their peculiar motion? But your clocks were never synced in that coordinate system, so no comparison can be made. All clocks will stay in sync forever in the inertial frame in which all of them are stationary.
The whole point is that they can't all be stationary because of the expansion of space: they have to be moving at different speeds through the expanding space in order to maintain their separation distances, and clearly that's going to show.
This is what I mean. I tell you what’s wrong, and you don’t hear it. Actually read what I say and don’t just assume I’m wrong.

You assert that it's wrong, but it isn't. Go back to the big version with the end clocks in distant galaxies maintaining their distance to us while those galaxies which are at rest in their local space move out past them. The end clocks must be ticking slower than the central clock is doing here. Clocks in those distant galaxies which are at rest are ticking at the same rate as the central clock here, but the end clocks aren't at rest in the places where they are..

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You didn’t sync your clocks ‘with space’, so it doesn’t show what you’re trying to show. If you did sync them that way (no proposed method to do this is mentioned in the paper, which is probably good since clocks ticking at different rates cannot be meaningfully synced)...

The method to sync them is spelt out clearly: a signal is sent out from the middle clock. It doesn't matter that the clocks are ticking at different rates because they will both start timing when that signal reaches them and we don't require them to remain in sync - the whole point is to see how much they go out of sync from that moment on.

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and this lag is exactly predicted by relativity as well, so it doesn’t falsify either interpretation.

It is not predicted by STR.

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Sending signals does not help maintain separation.

In the paper I described how it does. The clocks are inside boxes which shield them from gas and dust, while these boxes can change their speed and direction of travel with ion thrusters. These boxes can be buffeted about a bit while using the continual series of signals to maintain the right separation, transferring energy to the clock inside to make it maintain that separation with greater accuracy by shooting photons at it.

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After that, any subsequent signals will be received by the center in exact normal rate with no additional lag at all, even under your interpretation. You seem entirely unaware of this.

Of course they arrive without any lag: that's the whole point of them: they are used to maintain the separation, while this process does not update the clock in the box which is being used for the experiment.

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That’s a metaphysical assertion, not an empirical prediction. LET does not make different empirical predictions

It most certainly does. In LET the ticking rates of clocks are governed by absolute speeds through space, and the clocks have different absolute speeds through space.

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STR predicts that they are all moving at the same speed relative to each other and that they will all tick at the same rate.
STR makes no such metaphysical assertions, and you’ve declined to provide a reference where it does. STR only predicts what will be measured at specific events. Do you understand the difference?

Nonsense: STR is absolutely clear about what will happen to the three clocks which are not moving relative to each other - it does not allow them to tick at different rates. No reference is required for anything so fundamental to the theory.

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Your experiment can only be based on measurements, not on assertions. You can’t directly measure the separation between two things because you can’t be at both ends at once, so be very specific about how you’re going to know the separation of things and which coordinate system is used to express the result.

It is sufficient to maintain the separation which has its length measured using the frame in which the central clock is at rest: that's a trivial thing to measure as you can just ping a light pulse out to the ends and back and time that round trip.

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The travel time for the signals does indeed remain constant
Have you computed that or is this just another guess?

Why would you argue against that when you've made the same claim yourself? Remember this: "After that, any subsequent signals will be received by the center in exact normal rate with no additional lag at all, even under your interpretation. You seem entirely unaware of this."

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Using the cosmological coordinate system, the distance between clocks is always shorter than 50 AU due to length contraction of the moving ends. The proper separation of those clocks is increasing due to that motion slowing down over time.

You don't need to consider that as the separations are controlled by the central clock and must remain equal in length: they are not length contracted if the central clock is at rest. The central clock will complain if the signals are returned too soon.

Edit:

The problem of interference by gravity can be addressed by running a double-length version of the experiment alongside two sets of the standard length version. This places the clocks of different versions nearly side by side with clocks in other sets where they're at the same depth in gravity wells as each other. The bigger version will amplify the amount of "time dilation" caused by the difference in speed between its outer clocks while the component of slowing caused by gravity will not change. This should make it possible to separate the latter effect from the one we want to measure and allow the former to be measured with high precision (and with higher and higher precision as we continue to make more accurate clocks).
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 07/06/2021 03:20:59
Apologies. Been a while, but I’ve actually been running some numbers to get a better feel for how this all works. A great deal of the trouble with communication between us is your refusal to specify the coordinate system you’re using. It would be OK if you consistently used only one, but you don’t, and you switch back and forth between them and think some fact that’s true in one coordinate system (the sync of clocks, the distance between them, etc.) will be the same, when they’re not. It doesn’t help that you’ve picked an example that so completely local (only ~7 light hours between clocks) that the differences are immeasurable, but your proposal is to measure exactly that, and you will fail because A) you haven’t computed what you expect to measure, and B) You are not setting up the scenario using cosmological coordinates, but you switch to those coordinates when you want to assert something like this:
They'll only fail to lag if the space isn't expanding.
No coordinate system specified, so this metaphysical statement is ambiguous, and I didn’t assert otherwise. I said there would be no measured lag at the central point or wherever it is the measurements are being taken.
If you want to make a metaphysical assertion like that, be specific with a coordinate system, else we just keep going round in circles. Your paper says the 3 clocks are stationary relative to inertial frame A (the paper just says 'frame A', but doesn't say inertial). An inertial coordinate system is a different coordinate system than the one with the lag. Same spacetime, but different ordering of events. It’s a purely abstract difference. What matters is what is measured. That’s not abstract. That’s empirical, and the clock in the center will get signals at regular intervals from the end clocks, not lagged at all. This, not being a metaphysical assertion, must be true regardless of coordinate system of choice.
If the one clock is 7 light hours (LH) away as measured in inertial coordinates, then using the cosmological coordinates, the separation between those clocks will be < 7LH, but increasing. The time it takes to get a signal from the distant clock will be >7 hours and decreasing. This is because space expands between them while the signal is in flight, so it has further to go. Yes, the clock lags, but since the travel time is decreasing, the measurement taken at the central clock will be exactly 1 second apart, exactly as predicted by all theories involved.
All t his would be far more apparent if you scaled up the experiment to significant distances so the difference isn’t all the way into the 40th decimal place (I didn’t work it out, my calculator doesn’t have enough digits).
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Why are you trying to synchronise them by any frame other than the one in which the central clock is at rest?
Which frame would that be, the inertial one or the cosmological one? The central clock can be at rest in both of them. So still ambiguous. Be clear!
In cosmological coordinates, if two objects maintain separation distance at a given time (which is different than having identical velocity), then that constant separation distance will only be temporary, and they’ll start to move together and eventually meet. It would require proper acceleration of one or both of the objects to maintain this constant separation as measured in cosmological coordinates. This is one of the things I found out when working through the numbers.
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Both interpretations predict the exact same numbers. If you don’t get identical numbers, you’re making a mistake.
They don't.
Then either your proposal differs from LET, or you assert that LET is falsifiable. Somehow I don’t think your grasp of the theory is up to the latter, so you’re making up new stuff now.
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When you put the outer clocks in distant galaxies you can see that: they must tick much more slowly than the central clock.
Depends on your choice of abstract coordinate system. You never specify it. Want me to count how many times in one post you do it? This is about 4 now.
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With an aeroplane moving at 500 mph we have a loss of 3 millionths of a second per month.
5.  Maybe the aeroplane is more stationary when it flight. The H-K experiment certainly showed this with the westbound flight.
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Edit: … So, for every division of the speed by ten, we need a hundred times more resolution with the timers.
Yes.
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A thing in orbit cannot be inertial.
We don't allow the clocks to follow orbital paths.
You put in in interstellar space just outside the solar system. That puts it in orbit about the galaxy, involving acceleration that will dwarf the sort of time differences you’re trying to measure. That’s why I put it in a universe completely free of gravity and dark energy. Your setup needs to be stationary and needs to stay that way without proper acceleration.
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The method to sync them is spelt out clearly: a signal is sent out from the middle clock.
But are your outer clocks moving apart? In which coordinate system are they maintaining constant separation, because it can’t be both. You didn’t specify how you accomplished it. In particular, no mention of coordinate system was made. Things were not ‘spelt out clearly’. It very much matters because constant separation in one coordinate system gives different empirical results than constant separation in a different coordinate system.
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In the paper I described how it does. The clocks are inside boxes which shield them from gas and dust
There is no gas and dust in our ideal universe with no galaxy yanking the thing around. That’s a practical concern, but we’re nowhere near the practical yet.
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These boxes can be buffeted about a bit while using the continual series of signals to maintain the right separation, transferring energy to the clock inside to make it maintain that separation with greater accuracy by shooting photons at it.
Fair enough. We can have something shoot photons from the opposite direction to cancel that.  Or (if you accept the inertial coordinates) we could just attach all the parts to a stick or a slab of granite like they do in the lab. That method doesn’t work in cosmological coordinates.
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That’s a metaphysical assertion, not an empirical prediction. LET does not make different empirical predictions
It most certainly does. In LET the ticking rates of clocks are governed by absolute speeds through space
That’s not an empirical measurement. It’s a metaphysical assertion. You seem not to know the difference at all.
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STR is absolutely clear about what will happen to the three clocks which are not moving relative to each other - it does not allow them to tick at different rates.
STR makes no such assertion, and it certainly cannot be demonstrated from the premises.
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It is sufficient to maintain the separation which has its length measured using the frame in which the central clock is at rest
It’s at rest in both coordinate systems, so you still need to specify the coordinate system if you want to be clear.
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that's a trivial thing to measure as you can just ping a light pulse out to the ends and back and time that round trip.
That is an empirical prediction. Using cosmological coordinates, if you are stationary and there is a mirror out there held at a constant distance (as measured by said cosmological coordinates), the round trip times will shorten over time. The first one will take longer than the second one. Do you not know this? It’s kind of obvious if you think about it. Point is here, you can’t use such a method to maintain constant separation relative to that kind of coordinate system. It only works for inertial coordinates. Ditto with the granite slab.
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The travel time for the signals does indeed remain constant
Have you computed that or is this just another guess?
Why would you argue against that when you've made the same claim yourself?
Travel time is an abstract concept is constant in this scenario only using inertial coordinates.
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Remember this: "After that, any subsequent signals will be received by the center in exact normal rate with no additional lag at all, even under your interpretation.
That makes no mention of travel time (a relationship dependent on one’s abstract coordinate system of choice). It mentions only what will be measured at one location, which is a coordinate system independent empirical claim. You really don’t know the difference.
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Edit:
The problem of interference by gravity can be addressed
If you’ve no grasp of the ideal situation, it’s not time to try to deal with the real universe with its gravity and such.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 08/06/2021 02:19:26
Apologies.

None needed - this takes up time and your input is much appreciated.

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A great deal of the trouble with communication between us is your refusal to specify the coordinate system you’re using. It would be OK if you consistently used only one, but you don’t, and you switch back and forth between them and think some fact that’s true in one coordinate system (the sync of clocks, the distance between them, etc.) will be the same, when they’re not.

I always spell it out. When I talk about clocks being synchronised, I always say its done using the frame of reference in which the central clock is at rest, and then I refer how things are or might be moving relative to the local space where they are. Everything you need to know can be worked out from that with ease, so you can translate it to any other form you want.

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It doesn’t help that you’ve picked an example that so completely local (only ~7 light hours between clocks) that the differences are immeasurable, but your proposal is to measure exactly that,

You can imagine it at any size you like: the principle works the same way regardles of the size. The objective is obviously to try to measure it as soon as the technology exists to do so, and doing it as locally as possible reduces the delays it takes to get the components into the right places, which is why I kept it small. Perhaps it's too small, but perhaps not: a lot will depend on whether we've reached a point where it suddenly becomes much harder to make more accurate clocks or if we'll continue to improve their precision by orders of magnitude every decade. It wasn't so very long ago that LIGO looked impossible, and yet it's now up and running.

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and you will fail because A) you haven’t computed what you expect to measure,

There will be a size for the apparatus with which it would work using today's technology, but it could take thousands of years to get the clocks into place for that. Wait a few decades and that could reduce the time needed for the experiment down to one or two decades. The principle is clear though: the clocks are moving through space at different speeds while maintaining the same separation from each other, and that will lead to them ticking at different rates. You can pick up that kind of difference, and you can maintain the distances by pinging signals between them while keeping the round trip times constant with the central clock calling all the shots. If one of the end clocks finds that it needs to receive signals late in order to keep the central clock happy, that will be because that end clock is ticking more slowly, while the clock at the opposite end may find that it needs to receive them early because it is ticking faster than the central clock. That in itself will provide information about the absolute speeds of the clocks combined with any differences in their depths in gravity wells, though if we can predict most of the slowing caused by gravity, we'll be left with the differences cause by absolute speeds of the clocks. Some of the interference from gravity may not be easy to predict, but picture four sets of the apparatus set out as follows:-

       A_______________________________A_______________________________A
       B_______________B_______________B
       ________________C_______________C_______________C
       ________________________________D_______________D_______________D

Set of clocks A will produce a double size result in the absolute speed difference than you get from set B, C or D, but the size of the interference from gravity will be the same as it is for the shorter versions - that isn't going to double - and whatever gravity does to adjacent clocks from different sets will be practically the same as they're going to be moving only very slowly relative to each other within a few hundred metres of each other  throughout the experiment. This approach points the way to subtracting the unwanted signal and leaving just the one we seek to measure, whereupon we can do so with whatever precision our best clocks can provide.

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and B) You are not setting up the scenario using cosmological coordinates, but you switch to those coordinates when you want to assert something like this:
They'll only fail to lag if the space isn't expanding.
No coordinate system specified, so this metaphysical statement is ambiguous, and I didn’t assert otherwise. I said there would be no measured lag at the central point or wherever it is the measurements are being taken.

We set up the experiment without knowing what the cosmological coordinates are. We don't know which direction the experiment is moving through space in, or how fast. The experiment is designed to pin that down by measurement. There's nothing metaphysical about my statement: if there is no expansion of space where the experiment is done, there will be no difference in speed through space for any of the clocks, so they will all tick at the same rate (once you've subtracted any interference from gravity-well depth differences). If space is expanding there though, the clocks cannot all tick at the same rate and there will be differences in the timings (which persist after subtracting the influence of gravity). There is nothing ambiguous about that. Once we have the timings, then we can pin the right system of cosmological coordinates to the action.

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If you want to make a metaphysical assertion like that, be specific with a coordinate system, else we just keep going round in circles.

I'm the one avoiding going round in circles: I start from not knowing how the apparatus is moving relative to space, then make measurements with it which show how it's moving relative to the local space, and then we know when something is actually at rest here and can tie that to the coordinate system that you want to use, but correcting your desired coordinate system to fit with what is actually at rest here. You want me to start with something that the experiment is meant to pin down. You don't start with numbers you're trying to measure before you've measured them.

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Your paper says the 3 clocks are stationary relative to inertial frame A (the paper just says 'frame A', but doesn't say inertial). An inertial coordinate system is a different coordinate system than the one with the lag. Same spacetime, but different ordering of events. It’s a purely abstract difference. What matters is what is measured. That’s not abstract. That’s empirical, and the clock in the center will get signals at regular intervals from the end clocks, not lagged at all. This, not being a metaphysical assertion, must be true regardless of coordinate system of choice.

That is indeed the aim: the middle clock just sits there sending out and receiving signals, and once it has those signals returning at the right times it is satisfied that the outer clocks are maintaining a constant distance from it. If there's no significant change in gravity well depth for any of the clocks during the experiment, the clocks will tick at a constant rate and they can maintain station. The experiment is actually complete as soon as we've worked out the right timings for the end clocks to encounter the signals sent out to them from the middle clock because that is a measure of how much they are running slow or fast compared to the central clock.

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If the one clock is 7 light hours (LH) away as measured in inertial coordinates, then using the cosmological coordinates, the separation between those clocks will be < 7LH, but increasing. The time it takes to get a signal from the distant clock will be >7 hours and decreasing. This is because space expands between them while the signal is in flight, so it has further to go. Yes, the clock lags, but since the travel time is decreasing, the measurement taken at the central clock will be exactly 1 second apart, exactly as predicted by all theories involved.

If the central clock is sending out one ping per second, it should be getting back precisely one ping per second if the distance between the clocks is kept constant. However, for the clocks at the end, it (ignoring gravitational interference) can only be perceived as one ping per second if those clocks are moving through space at the speed as the central clock, and in expanding space. If one of them is moving at the same speed through space as the central clock, the third clock must be moving faster through space and will be ticking more slowly, so it will see less than a second passing between bouncing each ping back. That won't show up for a long time, of course, as we're looking for a tiny difference in clock rates, but it will accumulate.

Of course, we want the middle clock to stay still, so it can't make instant adjustments to the positions of the outer clocks, so it would be better to have the outer clocks try to maintain exact one-second intervals in the timings, leading to them gradually moving closer to the central clock if they're ticking faster than it is or gradually moving further away from the central clock if they're ticking slower. The central clock would then be able to read the distances to them by how early or late the signals come back from them, and this would also be a measure of the relative ticking rates, so that then provides information about which of the clocks is/are moving through space fastest.

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All t his would be far more apparent if you scaled up the experiment to significant distances so the difference isn’t all the way into the 40th decimal place (I didn’t work it out, my calculator doesn’t have enough digits).

You're free to scale it up to any size you like, such as having the end clocks in distant galaxies (while they move through them at relativistic speed in order to maintain their distance from us) while the central one is here in our galaxy. If alien scientists have been sending out one ping per second to them from here for ten billion years (rather than waiting for us to start the experiment) and those distant clocks are trying to ping them back to us such that they 
receive one ping per second, then their high speed of travel through space will make them tick slow, so they'll actually get further away from us over time while those galaxies move away from us faster than the clocks do. And we would receive the pings back from them with much more than one second of delay between them.

Let's maintain a huge separation though without any galaxies and have one of the end clocks be approximately at rest instead of the central one. What happens to the signals that we get back now? We send them out from our central clock at a rate which we think is one beep per second. The clock that's at rest receives them at a rate that it measures as one beep per second, but because it's ticking faster than our clock, it has to be moving away from us to maintain that, or rather we have to be moving away from it given that we're considering a case where it is at rest. The opposite clock will be ticking more slowly than ours, so for it to receive what it perceives to be one tick per second, it has to be moving towards us. This movement of the clocks will lead to the signals reaching us here coming back at a lower frequency from the clock that's at rest than from the clock that's moving fastest though space.

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Why are you trying to synchronise them by any frame other than the one in which the central clock is at rest?
Which frame would that be, the inertial one or the cosmological one? The central clock can be at rest in both of them. So still ambiguous. Be clear!

When you synchronise clocks in a test of STR where you send out a signal from a central clock, you obviously use the inertial frame in which the middle clock is at rest.

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In cosmological coordinates, if two objects maintain separation distance at a given time (which is different than having identical velocity), then that constant separation distance will only be temporary, and they’ll start to move together and eventually meet. It would require proper acceleration of one or both of the objects to maintain this constant separation as measured in cosmological coordinates. This is one of the things I found out when working through the numbers.

That's strange. If you imagine a pipe/tube with another pibe inside it and you have the inner one being pushed out of the outer one at a constant relative speed for a constant expansion rate, a roller sitting on the outer pipe might not be turning while a roller sitting on the inner pipe (away outer pipe) would have to rotate at a constant rate to stay the same distance from the first roller. If you use more than two pipes and have the rollers on the end ones, it's the same again: constant rotation rates for both rollers with a constant expansion rate for the system of untelescoping pipes. The same should apply for an infinite number of pipes. How would it be different for an expanding space, or there just some complication with the cosmological coordinates based on them using smaller numbers over time to represent a constant separation distance?

[Length limit causes a split here...]
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 08/06/2021 02:20:58
[...continuation]

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Both interpretations predict the exact same numbers. If you don’t get identical numbers, you’re making a mistake.
They don't.
Then either your proposal differs from LET, or you assert that LET is falsifiable. Somehow I don’t think your grasp of the theory is up to the latter, so you’re making up new stuff now.

Not at all. LET is absolutely clear that absolute speeds of movement through space dictate the ticking rates of clocks. We always have different absolute speeds through space for at least two of our three clocks if space is expanding, so LET predicts that they will tick at different rates. STR disagrees with that because it denies the existence of absolute speeds and it has all three clocks maintain the same relative speed of zero to each other. Now, in the latest version I'm allowing the outer clocks to move relative to the middle clock in order to maintain the arrival of beeps at a constant rate of one beep per second as measured by the receiving clock, but STR won't allow them to move relative to each other at all in this situation with this experiment because it demands that they'll all be ticking at the same rate. The real universe though will allow those clocks to move if the local space between them is expanding, and at least one of them will move relative to another of the clocks, thereby revealing the existence of absolute speeds and enabling us to work out when things are at rest. As soon as we know what's at rest, we know that a clock that's at rest is ticking faster than a clock that moves past it and that this is not a symmetrical relationship where it's just as valid to say that the clock moving past it is ticking faster than the one that's at rest: that relativity has been lost and we've replaced it with absolutes.

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When you put the outer clocks in distant galaxies you can see that: they must tick much more slowly than the central clock.
Depends on your choice of abstract coordinate system. You never specify it. Want me to count how many times in one post you do it? This is about 4 now.

You established earlier that all the galaxies must be approximately at rest as any great speed they could have had in the early universe would have been lost by now, so you should be able to agree that clocks at rest in those distant galaxies are going to be ticking faster than our outer clocks which are racing through those galaxies at relativistic speed relative to them and therefore at relativistic speed relative to the local space they're passing through, so they must be ticking more slowly than those clocks at rest in those galaxies. You can work out easily enough for yourself how to tie that to the coordinate system of your choice.

All that matters here is that we have three clocks spread out across a distance in expanding space. We can then speculate about which of them might be closest to being at rest and see what the consequences will be for each of the different possibilities. What we find when we do that is that we will get different measurements for the different cases, and STR doesn't allow that because it reveals different absolute speeds for the apparatus while carrying out experiments which STR insists are identical. Clearly STR isn't designed to handle expanding space, but the crucial thing that comes out of it failing in this circumstance is that it's plain wrong: it bans absolute speeds, but the real universe provides a way for us to pin them down thanks to that expansion, and as soon as we have that, relativity is out.

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You put in in interstellar space just outside the solar system. That puts it in orbit about the galaxy, involving acceleration that will dwarf the sort of time differences you’re trying to measure. That’s why I put it in a universe completely free of gravity and dark energy. Your setup needs to be stationary and needs to stay that way without proper acceleration.

It is sufficient just to maintain the alignment of the experiment and not worry about a constant acceleration to the side or ahead: the former has no impact on the result and the latter can be corrected for as we can calculate how much the clock deeper in the gravity well is ticking slow as a result of that. Doing a double sized version of the experiment alongside it will also reveal the amount of interference that can be attributed to gravity as the part of the signal we're trying to measure will double while the interference will not increase.

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The method to sync them is spelt out clearly: a signal is sent out from the middle clock.
But are your outer clocks moving apart? In which coordinate system are they maintaining constant separation, because it can’t be both.

Constant separation, going back to the method that tries to maintain that, has its standard meaning here: the clocks are not moving apart and the round trip distance for light signals is constant.

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You didn’t specify how you accomplished it. In particular, no mention of coordinate system was made. Things were not ‘spelt out clearly’. It very much matters because constant separation in one coordinate system gives different empirical results than constant separation in a different coordinate system.

Constant separation is constant separation. If you're using some kind of coordinate system in which the coordinates keep changing for two objects that are at a constant actual separation from each other, then that could lead you to think of diverging points with constant coordinates being constant separation, but that isn't constant separation.

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In LET the ticking rates of clocks are governed by absolute speeds through space
That’s not an empirical measurement. It’s a metaphysical assertion. You seem not to know the difference at all.

It has been demonstrated by experiment. You simply reject the results of those experiments on the basis that you can't pin down what's moving how fast, but the twins paradox using three clocks which never accelerate can only work if there are absolute speeds governing ticking rates. You simply rule it out by applying bad philosophy.

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STR is absolutely clear about what will happen to the three clocks which are not moving relative to each other - it does not allow them to tick at different rates.
STR makes no such assertion, and it certainly cannot be demonstrated from the premises.

You're just riding the ambiguities and trying to use whichever interpretation suits you from moment to moment. If you only go by a restricted set of its premises and claim that it is no more than that, those premises describe LET. STR is not LET, so you have to look at premises outside that restricted set to pin down what STR is supposed to be.

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It is sufficient to maintain the separation which has its length measured using the frame in which the central clock is at rest
It’s at rest in both coordinate systems, so you still need to specify the coordinate system if you want to be clear.

It's a constant separation in terms that people almost universally recognise as constant with light taking a constant time to make a round trip.

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that's a trivial thing to measure as you can just ping a light pulse out to the ends and back and time that round trip.
That is an empirical prediction. Using cosmological coordinates, if you are stationary and there is a mirror out there held at a constant distance (as measured by said cosmological coordinates), the round trip times will shorten over time. The first one will take longer than the second one. Do you not know this? It’s kind of obvious if you think about it. Point is here, you can’t use such a method to maintain constant separation relative to that kind of coordinate system. It only works for inertial coordinates. Ditto with the granite slab.

Then stop trying to impose that kind of coordinate system onto this. If I was using it, I'd say so.

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Travel time is an abstract concept is constant in this scenario only using inertial coordinates.

We're using a central clock which (ignoring the latest plan where we maintain constant timing gaps of exactly one second at the outer clocks) sends out signals and gets them back after a set length of time, so we don't need to care about coordinates of any kind: the outer clocks would then sit where they sit (or wander) and you can work out where that would be for the coordinate system of your choice.

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Remember this: "After that, any subsequent signals will be received by the center in exact normal rate with no additional lag at all, even under your interpretation.
That makes no mention of travel time (a relationship dependent on one’s abstract coordinate system of choice). It mentions only what will be measured at one location, which is a coordinate system independent empirical claim. You really don’t know the difference.

It appears to me that you're dragging in some weird coordinate system which makes out that things are at a constant separation when they're actually changing their separation and where constant travel times are asserted to vary too. I don't know why you feel the need to complicate something simple with that kind of stuff which misrepresents what's going on.

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Edit:
The problem of interference by gravity can be addressed
If you’ve no grasp of the ideal situation, it’s not time to try to deal with the real universe with its gravity and such.

It would clearly work fine in the ideal situation. The challenge is to turn it into a real-world (or real-universe) experiment, and the ability to isolate the impact of gravity and subtract it from the results is important because it enables us to have the ideal situation near to home. This way of doing it could eliminate the need to guestimate the amount of mass near the experiment (some of which may be dark matter) which could lead to different gravity-well depth for different clocks.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 08/06/2021 22:35:14
I always spell it out.
You still seem to be completely unaware that you’re doing it. As I said, we cannot communicate if statements are made that are only true in one coordinate system (or ‘CS’, I tire of typing it) and not another, but you are not explicit about which coordinate system that you think some non-empirical statement is true.
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When I talk about clocks being synchronised, I always say its done using the frame of reference in which the central clock is at rest
(1)See what I mean? Right out of the gate, in the same breath when you say you don’t do this. No CS specified. The one clock is at rest in either CS, so this is an ambiguous statement. Yes, I know we’re probably not talking about some inertial frame in which everything is moving, or some rotating frame or something, but this clock is at rest in both of the CSs that we’re discussing regularly. I pointed out this offense in several prior posts and yet you persist in doing it. I still don’t know which of the two coordinates you’re using.
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and then I refer how things are or might be moving relative to the local space where they are
With inertial coordinates, the entire system is local since there is no gravity and such. With cosmological coordinates, local is confined to ‘right here’ since it is the very deviations from that locality that you’re hoping in vain to measure.
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Everything you need to know can be worked out from that with ease
No, not with ease. It is actually totally unclear most of the time, so I need it to be explicit. You can do it with colors if you want, to save typing, or we can use {I} and {C} for inertial and cosmological coordinates respectively. Both LET and STR support both coordinate systems, so specification of one interpretation or the other does not make it clear which coordinate system is being chosen.
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You can imagine it at any size you like: the principle works the same way regardles of the size.
The example that I’ve been imagining involved an extreme example, which I’ve used to make some of the relationships clear.
{I}: When both clocks reads T=5.05 (age of universe if you will, and you said the clocks were to be in sync relative to {I}) and the length of our stationary granite slab being 4.95 light-units, a signal sent from the far end would be measured at T=10 at the center clock. I didn’t bother putting a 2nd object in the opposite direction.
Same scenario using {C}: The light is emitted at time T=1 from our far clock (It reads 5.05 because the clocks are not in sync in {C}) moving at a peculiar velocity of .98c towards us from a distance of 2.3 units.  It takes 9 units of time to reach the center clock.  The distance to the far emitting object is 2.3 and growing over time. There is no way any object can be there and maintain that 2.3 separation distance. Constant separation relative to a stationary object in {C} can only be maintained at peculiar velocities of about 0.76c and below. A clock at the end of the granite slab ticks once per dilated second and those ticks will be measured at the origin at one per second starting at time 10.
I didn’t specify units. You can make them seconds, years, billions of years, whatever. The points I’m trying to make can now be seen with only a couple digits of precision instead of scores of digits.
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The objective is obviously to try to measure it as soon as the technology exists to do so
First objective it to get the special mathematics straight. Second objective is to take a graduate level course in relativity to get the mathematics of the general case (including gravity and all).  If you do all that, third objective can be to find a practical way to verify that the two interpretations do not in fact predict different things. So stop worrying about technology when you’re grasp of the theory is still two steps behind.
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We set up the experiment without knowing what the cosmological coordinates are.
Why not? All you have to do is look out the window. You’re just trying (and failing) to find an empirical test to determine it from inside a box. The peculiar velocity of the solar system is well known and easily googled. OK, it is admittedly not known to the amazing precision you seem to want.
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I start from not knowing how the apparatus is moving relative to space
Your paper does not describe how the apparatus is moving relative to space. It describes it relative to frame A, which is presumably an inertial frame just like frames B through H. That was about the only CS reference in the paper. Since you are assigning {C} as absolute, that means signals from the end clocks are not maintaining constant travel time in {C}, but you seem to presume they do.
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That is indeed the aim: the middle clock just sits there sending out and receiving signals, and once it has those signals returning at the right times it is satisfied that the outer clocks are maintaining a constant distance from it.
(2). No CS specified. If the separation distance is maintained relative to one CS, then it isn’t constant as measured by the other. I pointed this out in the prior post, and yet you say ambiguous statements like this. You’re seemingly not reading my replies at all.
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If the central clock is sending out one ping per second, it should be getting back precisely one ping per second if the distance between the clocks is kept constant.
First of all. (3). You don’t say which coordinate system is used to describe the separation distance.
Second of all, what are these pings for? I thought there were clocks at the ends sending out signals every second. If they’re just echoing the pings from the center, then no clock is needed and you just need a mirror out there. Doesn’t matter since the signals will be measured every one second regardless of where the measurement takes place, assuming a marble slab maintaining constant separation distance, which means CS {I}.
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try to maintain exact one-second intervals in the timings, leading to them gradually moving closer to the central clock

You're free to scale it up to any size you like, such as having the end clocks in distant galaxies (while they move through them at relativistic speed in order to maintain their distance from us)
(4, 5) I cannot comment on you metaphysical assertions if I don’t know the CS you’re using. Said assertions are very much CS dependent.
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Let's maintain a huge separation though without any galaxies and have one of the end clocks be approximately at rest instead of the central one.
Pretty much what I describe above. I gave specific numbers for each CS, rather than making assertions without any CS. I wasn’t mirroring any signals. The clock at the far end starts sending one second pings starting at time 5.05 as measured on the clock there. The measurement takes place at the other end, stationary in either CS. That end receives the pings every one second. No signal is sent by the measurement end since I didn’t want to wait T=9.9 (empirical) for the round trip. I didn’t have 3 locations. Just two ends, with an observer at one end. Your have two such setups with a pair of ends in opposite directions doing symmetrical things, so I didn’t bother with the dup setup.
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What happens to the signals that we get back now? We send them out from our central clock at a rate which we think is one beep per second.
That wording only makes sense in the {C} CS, but I’ll still ding you (7) for not being explicit about it. My reply just below assumes {C}.
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The clock that's at rest receives them at a rate that it measures as one beep per second, but because it's ticking faster than our clock, it has to be moving away from us to maintain that, or rather we have to be moving away from it given that we're considering a case where it is at rest.
OK, the left clock is your stationary one, but the travel time between you and the left clock is always decreasing despite the steadily increasing separation distance, so the signals are received at the left every 1 second exactly despite your clock sending them less often than that. The only empirical measurement is seemingly on the left now, not where you are. Of course you’ll measure signals from the left every second as well if it’s sending them, this time dominated by the steadily increasing separation distance between them. Yes, I agree that the objects are moving apart despite being bolted to a common slab of granite.
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Which frame would that be, the inertial one or the cosmological one? The central clock can be at rest in both of them. So still ambiguous. Be clear!
When you synchronise clocks in a test of STR where you send out a signal from a central clock, you obviously use the inertial frame in which the middle clock is at rest.
So the paper implies. Not sure why sync is necessary, but OK. This procedure syncs the end clocks to each other relative to {I} but does not sync the middle one with either. I presume the objects are all stationary relative to {I}.
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In cosmological coordinates, if two objects maintain separation distance at a given time (which is different than having identical velocity), then that constant separation distance will only be temporary, and they’ll start to move together and eventually meet. It would require proper acceleration of one or both of the objects to maintain this constant separation as measured in cosmological coordinates. This is one of the things I found out when working through the numbers.
That's strange. If you imagine a pipe/tube with another pibe inside it and you have the inner one being pushed out of the outer one at a constant relative speed for a constant expansion rate
But that rate isn’t constant. It’s decreasing over time. You are also not maintaining constant separation relative to {C} in your description. You’re envisioning constant inertial separation, in which the objects indeed never meet. I’m saying (using {C}) that at a given time, object X is stationary and object Y is distance D from it. One second later the distance is still D. That’s temporary constant separation similar to a pair of cars following parallel paths on Earth’s surface. As time goes on, those paths don’t stay parallel and either the paths cross or at least one of the cars must apply lateral acceleration to maintain its constant separation from the other car. You’re describing tubes telescoping out, but unless those tubes apply a force to the ‘roller’ in your analogy, what the tubes do has no effect on whether the rollers will meet or not.
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a roller sitting on the inner pipe (away outer pipe) would have to rotate at a constant rate to stay the same distance from the first roller.
Obviously not. In 13.8 billion more years, a roller at the same 50 AU distance will be rolling at half the rate it is now. Surely this much is intuitive, no?
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You established earlier that all the galaxies must be approximately at rest as any great speed they could have had in the early universe would have been lost by now
No, I said that using {C}, the peculiar velocity of all galaxies is minimal. I would never have said the above without a frame reference since it just isn’t true using a different abstract choice of CS.
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so you should be able to agree that clocks at rest in those distant galaxies are going to be ticking faster than our outer clocks which are racing through those galaxies at relativistic speed relative to them and therefore at relativistic speed relative to the local space they're passing through, so they must be ticking more slowly than those clocks at rest in those galaxies.
No frame reference ( 8 ), so I would never agree to that. Using {I}, it is the distant galaxies that are moving fast and ticking slow. That’s why the references are needed when making such statements.
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All that matters here is that we have three clocks spread out across a distance in expanding space.
OK, I presume {C} due to the mention of expanding space. There is no ‘a distance’ in {C} since you made them a constant separation only in {I}.
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What we find when we do that is that we will get different measurements for the different cases
You’ve not established that. Back it with numbers, else you’re just asserting guesses. I put out numbers for my case, which involved a lot fewer significant digits. Tell me which of those numbers is wrong, because I have the same empirical measurements regardless of arbitrary choice of abstract coordinates.
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Constant separation, going back to the method that tries to maintain that, has its standard meaning here: the clocks are not moving apart and the round trip distance for light signals is constant.
OK, that’s only true in {I} since round trip time in {C} for a fixed separation goes down over time. Funny that you call your own coordinates {C} non-standard.
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Constant separation is constant separation.
(9)
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If you're using some kind of coordinate system in which the coordinates keep changing for two objects that are at a constant actual separation from each other
But the different CS defines what ‘actual separation’ is. ‘Actual separation’ is a metaphysical concept since it is a description of what is, not a description of what will be measured. So don’t assert constant separation without a CS. Instead, specify a measurement. Your constant round-trip light time counts as an empirical definition, so I accepted it. But it doesn’t correspond to constant ‘actual separation’ in your absolute universe you’re pushing, so you seem to be contradicting yourself. Look at my example at the top with wildly changing separation in {C} and also wildly changing transit time to travel from one end to the other. But round-trip time is fixed as measured by either end, and that empirical measurement is all that matters.
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It appears to me that you're dragging in some weird coordinate system which makes out that things are at a constant separation when they're actually changing their separation
You dragged in the ‘weird CS’ when you specified constant round-trip signal time. That’s the standard definition, and it uses {I}, not {C} which you are designating to be ‘actual’.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 10/06/2021 04:52:42
You still seem to be completely unaware that you’re doing it. As I said, we cannot communicate if statements are made that are only true in one coordinate system (or ‘CS’, I tire of typing it) and not another, but you are not explicit about which coordinate system that you think some non-empirical statement is true.

It should be obvious enough which kind of coordinate system is being used when we're testing STR against LET by describing things in the way that is normal when dealing with those theories. When I say we're using the frame in which the middle clock is at rest, that's the normal kind of frame used when discussing those theories. We don't switch to anything more exotic just because we've got expanding space in the experiment. When I consider the possibility that the central clock is at rest in the local space, again that's using bog-ordinary frames in the normal coordinate system, and the expansion of space then means that if the outer clocks are at a fixed separation from the central ones, they will both be moving through space. In the exotic coordinate system that you keep trying to switch to, you presumably still have an equivalent of "at rest" because the galaxies have all slowed (if they were ever moving fast in the first place) until they are nearly at rest, which means that even using that coordinate system you must still be able to understand that if the centre clock is at rest, the outer two cannot be if they are at a constant distance from the central clock (as measured by the observer at the middle clock who doesn't give a fig about other coordinate systems).

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Yes, I know we’re probably not talking about some inertial frame in which everything is moving, or some rotating frame or something, but this clock is at rest in both of the CSs that we’re discussing regularly.

If it's at rest in both of them, why do you need to be told which one of the two it is?

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I pointed out this offense in several prior posts and yet you persist in doing it. I still don’t know which of the two coordinates you’re using.

Given that I never use your weird coordinate system and no one else ever does when discussing experiments to test STR, I can't see why you think I'd suddenly be using it. I just thought you were expressing confusion about which frame of reference was being used, but I always spelt that out clearly.

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Constant separation relative to a stationary object in {C} can only be maintained at peculiar velocities of about 0.76c and below.

Clearly you've gone too extreme if you can't move the far clock fast enough to maintain the separation distance.

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We set up the experiment without knowing what the cosmological coordinates are.
Why not? All you have to do is look out the window.

The idea is to measure absolute speeds and the local rate of expansion which may not be the same as the overall rate of expansion, so we shouldn't make assumptions about how much expansion there will be here, although we would expect it to be reasonably similar, so that gives us an idea of the approximate size of the signal we're should be aiming to detect.

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You’re just trying (and failing) to find an empirical test to determine it from inside a box. The peculiar velocity of the solar system is well known and easily googled. OK, it is admittedly not known to the amazing precision you seem to want.

The intention is to measure the rate of expansion and pin down absolute speeds by an independent method. The existing way of doing it apparently isn't good enough for people who think STR is viable, but my method will show STR as so unambiguously wrong that it will lead to it being abandoned by the establishment.

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Your paper does not describe how the apparatus is moving relative to space.

Of course it doesn't. We don't need to know at the outset what the experiment is designed to find out through measurement. We can speculate about different cases of how it might be moving relative to space and see how the results would be different for those different cases. Then we run the experiment and get a result that tells us how the apparatus is actually moving relative to space. That's the whole point of the experiment.

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It describes it relative to frame A, which is presumably an inertial frame just like frames B through H. That was about the only CS reference in the paper. Since you are assigning {C} as absolute, that means signals from the end clocks are not maintaining constant travel time in {C}, but you seem to presume they do.

If you maintain constant distance between the outer clocks and the middle one, the signals from them will maintain a constant travel time in the frame used by the observer running the experiment from the central clock. He doesn't care what's happening in exotic frames which make it look as if constant lengths aren't constant.

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If the separation distance is maintained relative to one CS, then it isn’t constant as measured by the other. I pointed this out in the prior post, and yet you say ambiguous statements like this. You’re seemingly not reading my replies at all.

I just can't see the relevance of your weird CS which can't handle constant lengths as constant lengths. If it's to be used at all, it's mishandling of length should not be brought into this to obfuscate action that is very simple. The observer at the central clock is not using that CS for anything, and when he uses a powerful telescope (or pair of them to use parallax), he measures the distances to the clocks as constant. (In the most recent version of the experiment though, he sees the distances changing though because we then have the outer clocks moving away if they're ticking faster than the middle clock or moving towards the central clock if they're ticking slower than it as the outer clocks maintain the arrival of beeps at one per second by their own metering of time.)

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If the central clock is sending out one ping per second, it should be getting back precisely one ping per second if the distance between the clocks is kept constant.
First of all. (3). You don’t say which coordinate system is used to describe the separation distance.

I don't have to: it's perfectly clear that the signal must be travelling the same distance through space each time, so you can apply any CS you like to that.

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Second of all, what are these pings for? I thought there were clocks at the ends sending out signals every second. If they’re just echoing the pings from the center, then no clock is needed and you just need a mirror out there.

You need clocks at the ends to be slowed or speeded up in their ticking by their speed through space, so mirrors on their own won't hack it, but you still need continual round trips of signals in order to maintain a constant and exact separation distance between the clocks. Extra signals can be sent from each the outer clock to the middle one with time stamps stating what the outer clock's reading of time was when it was sent out, so if an outer clock is ticking slow, it might send out one of those every second as measured by that clock, which means that that set of signals would arrive at the central clock at a different frequency from the pings bounced back to the central clock.

All of that is the older version of the experiment though, and it's hard to maintain the right separation distances when signals have to do a complete round trip before the change in separation can be detected and a correction applied to the movement of the outer clocks, which is why the new version of the experiment is so much better: if the outer clocks simply try to maintain the same reception rate for the pings from the central clock, they can adjust immediately to any errors in their speeds. This approach leads to them not maintaining separation any more, but that's fine: the measurement becomes one of whether the separation grows, is maintained or reduces, and how fast it grows or reduces, and that can be measured with great precision by the return times of the pings to the centre clock.

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You're free to scale it up to any size you like, such as having the end clocks in distant galaxies (while they move through them at relativistic speed in order to maintain their distance from us)
(4, 5) I cannot comment on you metaphysical assertions if I don’t know the CS you’re using. Said assertions are very much CS dependent.[/quote]

Not so. A constant distance is a constant distance. A CS that says otherwise is not describing a constant distance, but a constant value in a system where a distance has a continually changing value representing it. You should not be allowing such a system to confuse you about what a constant distance is. The observer at the central clock knows what constant distance is (so long as he isn't accelerating, but this experiment would be able to measure any acceleration that's acting on it too just by repeating it and getting a different result each time as his absolute speed changes).

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What happens to the signals that we get back now? We send them out from our central clock at a rate which we think is one beep per second.
That wording only makes sense in the {C} CS, but I’ll still ding you (7) for not being explicit about it. My reply just below assumes {C}.

My wording makes full sense in the {I} CS.

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The clock that's at rest receives them at a rate that it measures as one beep per second, but because it's ticking faster than our clock, it has to be moving away from us to maintain that, or rather we have to be moving away from it given that we're considering a case where it is at rest.
OK, the left clock is your stationary one, but the travel time between you and the left clock is always decreasing despite the steadily increasing separation distance, so the signals are received at the left every 1 second exactly despite your clock sending them less often than that.

It looks as if I got the directions the wrong way round. If the outer clock is at rest, the middle one is ticking slower and is sending out beeps at less than one per real second, so it must be moving towards that outer clock rather than away from it if they are to be received by that outer clock at one beep per real second. For the other outer clock though, it would if it's at rest relative to the middle clock have to be moving faster through space and is ticking at a lower rate than the middle clock, so it must be moving away from the middle clock in order to perceive one beep per second. The idea for this was new as I wrote that post, so that opened the way to errors like inversion.

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The only empirical measurement is seemingly on the left now, not where you are. Of course you’ll measure signals from the left every second as well if it’s sending them, this time dominated by the steadily increasing separation distance between them. Yes, I agree that the objects are moving apart despite being bolted to a common slab of granite.

They aren't bolted to a common slab: they're separate and free to move relative to each other. The signals pinged back will also not arrive back at the middle clock at the same rate they were sent out: the rate will be lower if the distance between the clocks is growing and higher if it's reducing - it's like measuring the speed of cars with a radar gun.

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So the paper implies. Not sure why sync is necessary, but OK.

Synchronising them was needed with that version of the experiment in order to detect subsequent changes in synchronisation due to the clocks running at different rates.

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This procedure syncs the end clocks to each other relative to {I} but does not sync the middle one with either. I presume the objects are all stationary relative to {I}.

Correct, but if the pinged back signals arrive simultaneously at the middle clock after the right delay, then all three clocks will have been synchronised, the original signal being sent out early to antissipate the expected time taken for the signals to reach the outer clocks.

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But that rate isn’t constant. It’s decreasing over time.

It takes a very long time to change, so it can be ignored. In any case, when we switch to the new version of the experiment we no longer need to care about maintaining constant separation. Instead we look for whether clocks get closer together or further apart, and the speed of the change in their separation.

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a roller sitting on the inner pipe (away outer pipe) would have to rotate at a constant rate to stay the same distance from the first roller.
Obviously not. In 13.8 billion more years, a roller at the same 50 AU distance will be rolling at half the rate it is now. Surely this much is intuitive, no?

It does maintain the same rotation while it's on the same bit of tube though. At some point it will move onto a different pipe, but for a constant expansion rate of a given length of space, that pipe has to move faster by the time it reaches that roller, to the point that the roller must still be rotating at the same rate as before. We have to have a repeated creation of new pipes in between existing pairs of pipes in order to maintain the same local expansion rate between the two rollers, and that leads to an acceleration in the expansion of the universe as a whole (due to there being more and more space existing to expand). If we don't have that though, the local expansion of space would have to slow down, and then the roller would rotate more slowly. So long as the local expansion rate is constant though, that roller must rotate at a constant rate too. Which one of those is the universe thought to be doing?

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You established earlier that all the galaxies must be approximately at rest as any great speed they could have had in the early universe would have been lost by now
No, I said that using {C}, the peculiar velocity of all galaxies is minimal. I would never have said the above without a frame reference since it just isn’t true using a different abstract choice of CS.

Well, the problem with any alternative to that where they're moving away at high speed through space is that space would not be expanding.

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... so I would never agree to that.

In which case I won't bother using the extreme case with different galaxies again. I don't need it. It is sufficient to have expanding space and use relatively low speeds with the clocks not so distant from each other. The point of it was just to help you understand the experiment.

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OK, I presume {C} due to the mention of expanding space.

No. The mention of expanding space is not an invitation to use {C}. We're always using {I} with the experiment, but we're understanding that a line of three clocks that are at a constant separation will always have at least two of them moving at different speeds through space, and if your using of {C} for aiding your understanding of that helps, then you're free to use it for that, but it is sufficient to stick to {I} and recognise that the only location at rest in that frame that's actually at rest in space is the one where the central clock is.

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What we find when we do that is that we will get different measurements for the different cases
You’ve not established that.

Of course I've established it. The new version's the one you should switch to as it makes it much easier to see that different measurements will be made in different cases. The emitting clock (my central one) plays the tune while the receiving clock(s) dance(s) to its tune. If the emitter is ticking slower than the receiver, the receiver must move towards it to hear what it measures as one beep per second. If the emitter is ticking faster than the receiver, the receiver must move away from it to hear what it measures as one beep per second.

So, if the emitter is moving to the left while the clock to its left is the one at rest in space, those clocks must be getting nearer to each other. However, if the emitter is the one at rest in space, then the left clock has to be the one ticking more slowly, so the left clock has to be moving away from the emitter instead. In both cases, the left clock (the receiver) is the one that reacts to the signal by moving away from or towards the receiver, and which of those it does depends on which clock is ticking faster, and that depends on their absolute speeds through space.

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Back it with numbers, else you’re just asserting guesses.

I've given you numbers: less and more. Numbers with exact values are superfluous as you have a free choice of those and they will fit with what I stated. There is no guess involved. The separation distance is either growing (if the central clock is at rest), constant (if both clocks are moving at the same speed through space, while moving through the space local to them in opposite directions), or it's reducing (if the left clock is at rest). Those are stark differences.

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But the different CS defines what ‘actual separation’ is. ‘Actual separation’ is a metaphysical concept since it is a description of what is, not a description of what will be measured.

We don't care what the actual separation is: it is sufficient for it to be constant, and the observer with the central clock is happy that it is. With the newest version of the experiment, that observer can monitor the separation distances by the timings in the signals bounced back from the outer clocks and see whether they're constant, growing or reducing. He knows what constant means.

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But it doesn’t correspond to constant ‘actual separation’ in your absolute universe you’re pushing, so you seem to be contradicting yourself.

It's constant, but we only find out what the actual separation is after we know the absolute speed of the central clock.

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Look at my example at the top with wildly changing separation in {C} and also wildly changing transit time to travel from one end to the other. But round-trip time is fixed as measured by either end, and that empirical measurement is all that matters.

Well, I can't follow how your {C} works. I don't use it.

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You dragged in the ‘weird CS’ when you specified constant round-trip signal time. That’s the standard definition, and it uses {I}, not {C} which you are designating to be ‘actual’

I wasn't using {C} though. You dragged it in.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 10/06/2021 17:58:41
Had to split this topic since it is asserting inconsistent physics that supposedly “crack Relativity wide open”.
It should be obvious enough which kind of coordinate system is being used when we're testing STR against LET by describing things in the way that is normal when dealing with those theories.
But it isn’t. The same middle clock is stationary in both CS. Both intepretations support both CS, but LET goes so far as to call {C} ‘actual’, so you’re being self-contradictory when you say that the separation distance is both constant (using the {I} definition) and actually constant. It just cannot be both.
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When I say we're using the frame in which the middle clock is at rest, that's the normal kind of frame used when discussing those theories.]
We’re discussing both coordinate systems and both interpretations (same theory), so the CS is completely ambiguous when you say something like ‘the CS in which the clock is at rest’.
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When I consider the possibility that the central clock is at rest in the local space, again that's using bog-ordinary frames in the normal coordinate system, and the expansion of space then means that if the outer clocks are at a fixed separation from the central ones, they will both be moving through space.
That’s full of mixed CS references, making it baffling. By ‘ordinary’ I’m just guessing inertial coordinates {I}, but in {I} there is no space expansion. That expansion is only a valid concept in cosmological coordinates {C} where the separations are not fixed. You get nonsense results if you mix coordinates in one sentence like that.

Edit: I found the correct name of the coordinates for our simplified universe without gravity. {C} is hyperbolic coordinates as used for instance by the Milne model, a limit of the standard FLRW model as energy density approaches zero. Maybe I should call the special (gravity free) case {H} and reserve {C} for the general case. The mathematics I'm discussing is part of priority 1: Understanding the special no-gravity case. Priority 2 was to take the graduate level course in relativity to enable us to discuss the general case including gravity. I seriously doubt either of us is going to get that far. My tensor calculus is a bit rusty.

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In the exotic coordinate system
Which one is ‘exotic’? The one asserted to be ‘actual’ by LET? Now you’re giving weird names to the CSs instead of using {I} and {C}. That’s not explicit since I have not been informed which CS you consider to be exotic.
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If it's at rest in both of them, why do you need to be told which one of the two it is?
Because you subsequently draw a conclusion or make some assertion that is only valid in one kind of CS and not the other.
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Given that I never use your weird coordinate system and no one else ever does when discussing experiments to test STR
Inertial coordinates are weird? Distances are measured with a tape measure or printed on the granite slab to which our clocks and mirrors are bolted. That’s not weird. That’s the most simple CS that everybody uses.
I will quote your definition of the ‘weird’ CS:
It appears to me that you're dragging in some weird coordinate system which makes out that things are at a constant separation when they're actually changing their separation and where constant travel times are asserted to vary too.
That ‘weird’ CS happens to be {I}: inertial coordinates, which everyone discusses in STR introductions. Using that CS, our devices are at constant separation due to A) being bolted to our granite slab and B) the constant measured round trip time between the devices, per your specification. Yes, if {C} is designated as ‘actual’, then these devices are actually changing their separation. ‘Actual’ is a metaphysical premise assigned by interpretations like LET. STR doesn’t assert that any non-empirical quantity like ‘distance’ is actual. It is simply computable given an arbitrary choice of abstract coordinate system. Both {I} (the weird CS) and {C} (perhaps the ‘exotic’ CS) are valid abstract choices and yield different separation distances, so STR does not assert any of those choices to be preferred and thus more actual.
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Constant separation relative to a stationary object in {C} can only be maintained at peculiar velocities of about 0.76c and below.
Clearly you've gone too extreme if you can't move the far clock fast enough to maintain the separation distance.
Consider a galaxy currently 25 billion light years away as measured in {C}. How fast (peculiar velocity, or actual speed as you put it) would a rock there need to go in order to maintain constant proper distance from Earth?  It would have to outrun light, so it cannot be done. Do you not know this simple tidbit? I’ve ‘gone to extreme’ when I point out simple things like this that are published in countless textbooks?
I thought you wanted my input, but you’re seemingly just here to bash anything I say, which is another reason for the thread to be moved to the ligher side. Suppose for a moment that I know at least a little about cosmological coordinates. Please don’t assume the roll of the troll.
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If you maintain constant distance between the outer clocks and the middle one, the signals from them will maintain a constant travel time in the frame used by the observer running the experiment from the central clock. He doesn't care what's happening in exotic frames which make it look as if constant lengths aren't constant.
The frame in which the separation distance is changing is the one you’re designating to be ‘actual’. So {C} is the exotic one now? That’s switching from how you assigned ‘exotic’ above. Please use {I} or {C} since your designation of ‘exotic’ seems to be a moving target.
A CS apparently becomes ‘weird’ or ‘exotic’ when you want to assert something that differs from the mathematics of the situation, a sort of argument from incredulity fallacy.
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I just can't see the relevance of your weird CS which can't handle constant lengths as constant lengths.
So LET is irrelevant? It’s the one that asserts that the lengths are changing. I can agree with that assessment.
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A CS that says otherwise is not describing a constant distance, but a constant value in a system where a distance has a continually changing value representing it. You should not be allowing such a system to confuse you about what a constant distance is.
Now LET ‘should not be allowed’. Hmm…
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If it's to be used at all, it's mishandling of length should not be brought into this to obfuscate action that is very simple.
Your lack of understanding does not demonstrate that {C} mishandles lengths. I gave a clear example that shows the length changing. All you need to do is scale up your distance like I did. 100 AU is nothing. {C} is the coordinate system of choice for describing the universe as a whole. Almost all current distances to far galaxies are expressed using it. Inertial coordinates are confusing at best at the gigaparsec scale, and inapplicable in reality since inertial coordinates only are applicable to the special case that is free from distortions from gravity and dark energy.
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(3). You don’t say which coordinate system is used to describe the separation distance.
I don't have to: it's perfectly clear that the signal must be travelling the same distance through space each time, so you can apply any CS you like to that.
You do have to because the separation distance is changing in {C}, as is the travel time. The outgoing signal takes longer than the return one, but the round trip will be identical over time as measured by either end. Again, this was illustrated in my example, something you’ve just ignored. Why? If my numbers are wrong, tell me where. If they’re not, they show many of the relationships I’ve been pointing out such as changing separation distance and signal travel times each way, all without needed scores of digits of precision.
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Second of all, what are these pings for?
you still need continual round trips of signals in order to maintain a constant and exact separation distance between the clocks.
The granite slab wasn’t enough? Signals don’t maintain a distance. They only verify it, and only relative to inertial (or ‘weird’ as you put it) coordinates.
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My wording makes full sense in the {I} CS.
OK. You should have been explicit about it then. Me having to guess doesn’t work.
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It looks as if I got the directions the wrong way round. If the outer clock is at rest, the middle one is ticking slower and is sending out beeps at less than one per real second, so it must be moving towards that outer clock rather than away from it
Regardless of which end is closest to being at rest in {C}, they’re all moving apart in {C} if they’re stationary in {I} as specified. My example, had you paid attention to it, puts real numbers to this.
This is readily apparent with the granite slab, the peculiar movement of which is slowing over time, and thus it loses length contraction, always getting closer to its proper length but never fully getting there.
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They aren't bolted to a common slab: they're separate and free to move relative to each other.
You said they were stationary relative to some inertial frame. I cannot think of a better way to maintain that separation than with said slab. It’s how they do it in all the labs. OK, it’s not always granite. But bolted down is far more reliable than free-floating objects. Imagine LIGO trying to maintain its fixed (to 23+ digits of precision) distances by just praying that no forces act on its free-floating mirrors.
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It's like measuring the speed of cars with a radar gun.
Radar guns use Newtonian mechanics.
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Synchronising them was needed with that version of the experiment in order to detect subsequent changes in synchronisation due to the clocks running at different rates.
But 1) the sync wasn’t done with the center clock. Only the two end clocks are synced (and only relative to {I}), and 2), the change in sync cannot be detected without presumption of a CS. Only clocks in each other’s presence can be compared independent of a CS choice.
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if the pinged back signals arrive simultaneously at the middle clock after the right delay, then all three clocks will have been synchronised, the original signal being sent out early to antissipate the expected time taken for the signals to reach the outer clocks.
I’ll accept that. The center clock sends the signal at T1 which zeroes the outer clocks, and gets the reply at T2, so it sets its current time to (T2-T1)/2. That works in {I}.
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It takes a very long time to change, so it can be ignored.
You’re proposing an experiment that you assert is going to differ in only the 40th digit, and you’re choosing to ignore things that change over time. This is why I scaled it up, so you’re not tempted to ignore significant things.
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In any case, when we switch to the new version of the experiment we no longer need to care about maintaining constant separation. Instead we look for whether clocks get closer together or further apart, and the speed of the change in their separation.
They’ll stay at a fixed distance relative to {I} if they start that way and no external forces act on them. The lack of the granite slab just makes it impractical to achieve it. The slab doesn’t apply a force to keep the distance fixed, it only serves to resist said external forces and to force a visual reminder of which CS is being referenced when we say the distance is fixed.

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It does maintain the same rotation while it's on the same bit of tube though.
I’m picturing a lot of little tubes all telescoping together, not widely separated tubes with discreet expansion points now and then. The latter is just integration with insufficient granularity. Yes, it is very much an exercise in calculus to describe anything going on in {C}. What do you think I was doing for those 3 days I didn’t reply?
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but for a constant expansion rate of a given length of space
Space expansion is not constant, despite the term ‘Hubble constant’. The expansion rate is effectively 1/T where T is the age of the universe. That obviously changes as the universe ages. An actual constant expansion rate would result in exponential expansion, not linear expansion. It’s only called Hubble’s constant because humans haven’t been around long enough for the value (known to 2 digits at best) to have changed significantly. Assertion of the expansion rate being a constant (especially in the past) very much contradicts the big bang theory. The FLRW model suggests that when dark energy is completely dominant, the rate will settle on an exponential actual constant of around 57 km/sec/mpc which ceases to be a function of time, but our ideal model has flat expansion with no dark energy.
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Well, the problem with any alternative to that where they're moving away at high speed through space is that space would not be expanding.
That’s right. Different frames assigned different spatial coordinates to events. The presence of gravity and dark energy make inertial coordinate system inapplicable, but they’d be fully applicable in the absence of those two factors. This is what I’ve been trying to show.
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we're understanding that a line of three clocks that are at a constant separation will always have at least two of them moving at different speeds through space
Sorry, no. {I} assigns constant spatial coordinates to all the objects in the scenario. Nothing is moving through space in {I}. Expanding space is only a property of {C}. All the same events, but different assignment of coordinates to each of them. Such an assignment is purely abstract and cannot make a physical difference to any empirical measurement.
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You’ve not established that.
Of course I've established it.
No numbers, so not established. The rest is unbacked assertions.
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The separation distance is either growing (if the central clock is at rest), constant (if both clocks are moving at the same speed through space, while moving through the space local to them in opposite directions), or it's reducing (if the left clock is at rest).
No CS reference, but as you set it up, separation is constant in {I} and increasing in {C} regardless of which end has the higher peculiar velocity. Any empirical measurement will be unaffected by this motion.
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I've given you numbers: less and more.
Well above are my numbers, which contradict yours. I gave specific numbers in my example which you did not contest, so your less-and-more guess contradicts that.
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We don't care what the actual separation is: it is sufficient for it to be constant
But you’ve not set up the scenario that way. You set it up to have constant round trip signal time, which can only be had with increasing actual separation relative to {C} which LET asserts to correspond to ‘actual’.
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Well, I can't follow how your {C} works. I don't use it.
And yet LET does. It’s the CS you assert to be ‘actual’. Yes, I’ve very much noticed that you don’t know how it works, but despite that admission, you sure do make assert a lot of guesses about it.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 11/06/2021 06:41:02
Had to split this topic since it is asserting inconsistent physics that supposedly “crack Relativity wide open”.

It isn't. It's fully consistent.

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It should be obvious enough which kind of coordinate system is being used when we're testing STR against LET by describing things in the way that is normal when dealing with those theories.
But it isn’t. The same middle clock is stationary in both CS.

Only if it's actually at rest in space, but we don't know that at the start, so the middle clock could easily be at rest in the initial frame that we use while it's actually moving through space.

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Both intepretations support both CS, but LET goes so far as to call {C} ‘actual’, so you’re being self-contradictory when you say that the separation distance is both constant (using the {I} definition) and actually constant. It just cannot be both.

When we're comparing LET with STR with the experiment, we're using the same {I} frame for both and we never use a {C} frame at all.

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When I consider the possibility that the central clock is at rest in the local space, again that's using bog-ordinary frames in the normal coordinate system, and the expansion of space then means that if the outer clocks are at a fixed separation from the central ones, they will both be moving through space.
That’s full of mixed CS references, making it baffling.

It isn't at all baffling. We are using {I} frames while also recognising that space is expanding, and that's something you should be able to visualise with ease. It simply means that light can't actually be moving at c relative to the frame in all locations, but we are still using {I} frames regardless just as if light is moving at c relative to the frame thoughout. The whole point is that the result of the experiment will reveal what light is actually doing - we don't program the result in at the beginning, but uncover it at the end.

We are testing STR against LET with an experiment where {I} frames are used at all times. When we discuss the experiment we can talk about other CSs if you like, and the expansion, but that's all in the meta. The person carrying out the experiment simply performs it and makes measurements, and he finds that when he sets it up the same way but with the apparatus moving faster to the left or right relative to the first running of it, he gets different results each time, while STR insists that he should get the same result each time. When he then tries to make sense of those results, he then thinks about how space is expanding, and at that point he realises that his measurements enable him to pin down the absolute speed of the apparatus and to measure the amount of expansion of space locally.

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By ‘ordinary’ I’m just guessing inertial coordinates {I}, but in {I} there is no space expansion.

There is here: the observer doesn't know if there's any space expansion or not, and he's doesn't need to use anything other than an {I} frame. A null result in which the outer clocks maintain their original distance from the middle clock will actually prove that there isn't any expansion, while any other result will break STR, and if that happens, that's when the observer realises that there's expansion, but he's found that out just by using a single {I} frame.

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If it's at rest in both of them, why do you need to be told which one of the two it is?
Because you subsequently draw a conclusion or make some assertion that is only valid in one kind of CS and not the other.

The conclusions come at the end after STR has broken. We are testing STR in standard STR ways, but it will break STR if the space is expanding sufficiently fast for the effect of that to show up in the results.

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Given that I never use your weird coordinate system and no one else ever does when discussing experiments to test STR
Inertial coordinates are weird? Distances are measured with a tape measure or printed on the granite slab to which our clocks and mirrors are bolted. That’s not weird. That’s the most simple CS that everybody uses.

{I} isn't the one I'm calling weird. The weird one is the one you keep dragging in to try to disrupt things while everything about the set up and carrying out of the experiment sticks to using {I}. The weird CS is your {C} which makes out that constant separations as aren't constant.

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I will quote your definition of the ‘weird’ CS:
It appears to me that you're dragging in some weird coordinate system which makes out that things are at a constant separation when they're actually changing their separation and where constant travel times are asserted to vary too.
That ‘weird’ CS happens to be {I}: inertial coordinates, which everyone discusses in STR introductions.

My description there only fits {C}, as the word "actually" reveals. You likely misinterpreted it because I referred to things actually changing their separation there rather than using an example where they're actually maintaining their separation as before.

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Consider a galaxy currently 25 billion light years away as measured in {C}. How fast (peculiar velocity, or actual speed as you put it) would a rock there need to go in order to maintain constant proper distance from Earth?  It would have to outrun light, so it cannot be done. Do you not know this simple tidbit? I’ve ‘gone to extreme’ when I point out simple things like this that are published in countless textbooks?

Don't blame me if you've gone so extreme that you have to move the clock faster than light.

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I thought you wanted my input, but you’re seemingly just here to bash anything I say, which is another reason for the thread to be moved to the ligher side. Suppose for a moment that I know at least a little about cosmological coordinates. Please don’t assume the roll of the troll.

I did want your input, and it's been very useful. I have to thank you for putting in the time you have on it, and I'm getting much more useful feedback from you than from anywhere else, which reveals a lot about your quality. There's a reason why I've always rated you highly, regardless of how much we disagree about things. You have advanced this considerably.

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So {C} is the exotic one now?

{C} is the only one I've ever called exotic.

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I gave a clear example that shows the length changing.

I couldn't work out what you were doing with it.

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...inertial coordinates only are applicable to the special case that is free from distortions from gravity and dark energy.

Inertial coordinates are absolutely applicable to a test of STR such as this experiment.

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The outgoing signal takes longer than the return one, but the round trip will be identical over time as measured by either end.

Which is a constant travel time. When the separation is constant, the travel time does not vary. The travel time out doesn't vary. The travel time back doesn't vary.

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Again, this was illustrated in my example, something you’ve just ignored. Why? If my numbers are wrong, tell me where. If they’re not, they show many of the relationships I’ve been pointing out such as changing separation distance and signal travel times each way, all without needed scores of digits of precision.

Where have you got changing separation? In an example where the outer clocks are in distant galaxies but are moving through them at speeds such that they maintain distance from the middle clock, they clearly have constant separation. If you have to accelerate them to maintain that separation, you are free to do just that. I cannot see how you're making constant separations non-constant.

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The granite slab wasn’t enough?

I never used one. No practical experiment of any size can.

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Signals don’t maintain a distance.

Signals enable adjustments to maintain separation. It's the standard way to do things in space.

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This is readily apparent with the granite slab, the peculiar movement of which is slowing over time, and thus it loses length contraction, always getting closer to its proper length but never fully getting there.

Why have you got the slab slowing down if the central clock is at rest? There will be no change in length whatsoever caused by length contraction in such a case, and that's the case we were discussing when we went big with the experiment with the middle clock at rest here in our galaxy. The separations are thus constant.

However, if I missed something about the middle clock not being the one at rest, then that's different. If you have the middle clock slowing down, which isn't something I considered as I don't think it will slow down at all, then that would result in a change in length contraction, so if that's the point you've been trying to make, I can see it now. I was always assuming that it wouldn't slow, or at least not significantly, but what if it slows just enough to mask the effect I'm trying to measure? Perhaps you've already shown that that's the case without me recognising what you'd done. If so, then it would be another extraordinary aspect of the mathematics of relativity that maintains its ability to mask absolute speeds even in expanding space, and that would be great in itself as it would be yet another illustration of that extraordinary nature of relativity, but there must be some way to show up the difference because we have such a clear way with the clocks, watches and miniwatches created near the time of the big bang, so I don't hold out much hope for your approach. Let me explore it though now:-

In the case with the middle clock at rest, the outer clocks are moving through space (with that space moving out past them away from the middle clock), leading to them ticking more slowly than the middle clock. That will lead to them both having to move away from the central clock in order to receive the required perceived ticking rate, though as they do this they will also reduce their speed through the space that's local to them, so that leads to their clocks ticking faster, thereby suppressing the extent to which they have to move away from the central clock, but they will still both continually move away from it, and the result of doing so will be that the experiment will stretch to a longer length through space and amplify the speed of movement of the outer clocks away from the middle one while the observer at the middle clock gets the bounced back signals returning to him at a lower frequency than they were sent out from there, and he also sees the outer clocks get smaller: there is no length contraction change for him to cancel out that sight of them moving away.

Shifting then to a case where the middle clock is moving through space but decelerating a little during the experiment due to the expansion of space, what happens now? At all times throughout the experiment it will be moving in a single direction, but the slight deceleration will result in its ticking rate increasing a little as the experiment runs. If we have one of the outer clocks at rest in its local space, then that outer clock is ticking at a faster rate than the middle clock, and in such a case, we have the central clock initially sitting with space moving out through it away from the outer clock that's at rest. We'll ignore the other outer clock for now and just call the clock that's initially at rest the outer clock. The middle clock is ticking slower than the outer clock, so the outer clock has to move towards it in order to maintain the required perceived beep arrival rate in the signal it's receiving from the middle clock, but as it does so, that movement leads to it ticking at a lower rate as it starts to move slowly through space, so that suppresses its speed towards the centre clock a bit, but because it will continue to have a lower speed through space than the middle clock, it's not going to stop or move backwards: it continues to move towards the middle clock throughout the experiment. As the middle clock decelerates though, it (middle clock) ticks faster, so that leads to a further reduction in the speed at which the outer clock moves towards it because the beeps are sent out at a higher rate than before, but again, so long as the middle clock continues to move in the same direction, the outer clock continues to move towards it. We have a distinct physical difference from the first case in that the outer clock is moving towards the middle one instead of away from it, although it's just possible that it might not look that way to the observer at the middle clock from the returning ping rate. The beeps are bounced back from the outer clock in such a way that they have a higher frequency than they were sent out with, but as the middle clock slows down its speed of movement through space (assuming that really happens), it sends beeps out faster (while always ticking more slowly than the outer clock and while the outer clock is always reducing the separation distance), but perhaps the returning pings could still come back to the middle clock at a lower frequency than they were sent out, thereby making it look as if the outer clock is moving away. The outer clock is always getting closer to it though in reality, so which effect wins out? I don't know: that's something that does need a set of specific numbers to be worked out for it, and maybe you've already done that and found complete masking of the difference between the two cases. Fortunately though, I don't need to rush to work out numbers because we can simply switch to a different method of measuring distance to settle the matter. With the middle clock slowing down, any length contraction on its parallax measurements of the distance to the outer clock will show the outer clock to be getting closer over time rather than further away, quite in addition to the fact that it is physically getting closer, so the observer sees it growing larger in his telescope, and the reduction of the distance between them is amplified for the observer as length contraction is lost - if there was a rod sticking out from the middle clock to the outer clock, for example, that rod would lengthen as the length contraction is removed, but the outer clock would not stay at the far end of the rod - the end of the rod and the outer clock would move away from each other with the outer clock continuing to get closer to the middle clock while the end of the rod extends further away. We thus still have a clear effect that is not being masked.

So no, this reduction of the middle clock's speed through expanding space does not mask absolute speeds. We still get different measurements from the experiment depending on the speed of the apparatus through space and there is no escape route for STR. The content of the previous two paragraphs needs to be checked rigorously though to see if it contains any errors, so that's the key thing to focus on.

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But 1) the sync wasn’t done with the center clock. Only the two end clocks are synced (and only relative to {I}),

All three ended up synchronised: we kept the separation distances constant and we assume half the return trip time is the time to adjust the centre clock by to match the outer ones. It does go wrong though if the central clock decelerates, but I'd assumed that there was no deceleration of any significance during the course of the experiment, if there's any such deceleration at all. In any case though, there was never any actual need to synchronise the middle clock with the others as what it's looking for is delays over time on signals sent from the other clocks which are sent out at their preceived regular intervals, which also means that the correct synchronisation of the two end clocks isn't crucial either. It simply made the description of the experiment simpler.

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It takes a very long time to change, so it can be ignored.
You’re proposing an experiment that you assert is going to differ in only the 40th digit, and you’re choosing to ignore things that change over time. This is why I scaled it up, so you’re not tempted to ignore significant things.

Well, I'm glad you drew attention to that. Clearly it needs to be addressed.

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In any case, when we switch to the new version of the experiment we no longer need to care about maintaining constant separation. Instead we look for whether clocks get closer together or further apart, and the speed of the change in their separation.
They’ll stay at a fixed distance relative to {I} if they start that way and no external forces act on them.

Not in the new version. They have ion drives or gas jets and actively adjust their speed to maintain a constant perceived beep rate from the central clock.

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It does maintain the same rotation while it's on the same bit of tube though.
I’m picturing a lot of little tubes all telescoping together, not widely separated tubes with discreet expansion points now and then. The latter is just integration with insufficient granularity. Yes, it is very much an exercise in calculus to describe anything going on in {C}. What do you think I was doing for those 3 days I didn’t reply?

I'm picturing them in the same way. To maintain the expansion rate you actively have to accelerate each little tube as it moves away from where it set out, and that keeps the roller going round at a constant rate, so there's no slowing of its speed of movement through space. The other roller is not going round (i.e. is at rest in its local space), and the distance between the rollers is constant. That suggests to me that there will be no slowing of the content of the universe through space, so if the galaxies had all started out moving in the same direction through space at relativistic speed, they'll still be doing so.

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we're understanding that a line of three clocks that are at a constant separation will always have at least two of them moving at different speeds through space
Sorry, no. {I} assigns constant spatial coordinates to all the objects in the scenario. Nothing is moving through space in {I}. Expanding space is only a property of {C}.

You're missing the point yet again. We are using {I} even though we're talking about space expanding. The whole experiment is carried out under {I} while the expanding space part of it is part of the discussion as to why there isn't a null result and STR breaks. The person doing the experiment is an STR fan who is doing an experiment which he hopes will "confirm" STR yet again by producing a null result (we don't need to tell him otherwise, and we don't want to confuse him up front by discussing space expanding), so it's all done using {I}. The results though show that it breaks, and that's when the expansion of space comes into play as an explanation, and absolute speeds are pinned down. You keep trying to ram the cart in front of the horse.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 11/06/2021 21:16:27
Thanks for moving your reply to Jeffrey. I couldn't think of a way to split the post except to append the reply to one of your prior posts. I removed that now from the OP on this thread so it reads like an OP now.

My tone seems to be changing with recent posts. It is becoming more clear that you have no desire to learn anything, but just want to add yourself to the list of those choosing to misunderstand relativity like all the others. I have my suspicion as to why he's so often the target. Publish your paper and it might be well received by your peers, those peers being said 'all the others'.
If you need help, pony up numbers or take apart the ones in my example, or at least use the "Say Thanks" action so my replies appear appreciated. But the continued unbacked and unquantified assertions seem to be your only tactic, and there seems to be no point in endlessly repeating how those assumptions are merely just that.

When we're comparing LET with STR with the experiment, we're using the same {I} frame for both and we never use a {C} frame at all.
You use it all the time, anytime you use the word ‘actual’. You assert that the far clock lags the (assumed) stationary near clock, which it doesn’t relative to {I}, but only relative to {C}. To say you never use {C} is to deny your favorite coordinate system.
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It isn't at all baffling. We are using {I} frames while also recognising that space is expanding
No. Expansion is a coordinate effect, and thus it isn’t expanding under {I}, only {C}. The fact that there is expanding aether going on is metaphysically irrelevant if the stuff cannot be measured. Any aether reference is a reference to {C} since that’s the CS that defines its motion. Calling aether ‘space’ is misuse of an abstract term since space is coordinate dependent, a purely abstract and arbitrary assignment of time and location to every event. So space does not expand under {I} because we’ve assigned locations based on our granite slab, and not on anything else.
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It simply means that light can't actually be moving at c
See? There’s that {C} reference. Just because you decline to explicitly type {C} despite my request for you to do so, your use of ‘actually’ is a reference to it. You don’t consider {I} to be actual and relativity theory doesn’t designate any metaphysical status of ‘actual’ to any particular coordinate system.
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The whole point is that the result of the experiment will reveal what light is actually doing
And my point is demonstrate where your guesses in this regard are incorrect. No test can distinguish actual from, well, not actual. There is zero empirical difference between the interpretations except apparently what it’s like to fall into a black hole.
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We are testing STR against LET with an experiment where {I} frames are used at all times.
Then you will get {I} results in both theories, or if this is reality and not our gravity-free ideal universe, you’ll get inapplicable results in both theories because {I} does not apply to non-Minkowskian spacetime. I told you that priority 2 was to learn all of relativity, but for the purpose of this topic, the special case is enough.
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we can talk about other CSs if you like, and the expansion, but that's all in the meta.
Other CSs are just different abstract assignments of time and location to the same physical events. Meta doesn’t come into play until you assert one such arbitrary assignment to be more actual, and that philosophical premise has no change on what is measured.
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The person carrying out the experiment simply performs it and makes measurements, and he finds that when he sets it up the same way but with the apparatus moving faster to the left or right relative to the first running of it, he gets different results each time, while STR insists that he should get the same result each time.
That would be remarkable, I agree since it would falsify both interpretations. I’m trying to show you how LET does not predict different measurements. Relativity supports {C} just as much as LET, but without the metaphysics. So some amateur comes in with a demonstrable misunderstanding of the mathematics, and thinks he’s spotted an inconsistency between two different abstract choices of event ordering and will not listen to corrections on his misconception. The world goes on unperturbed. You ask for my help, but instead of taking it, you turn it into some kind of debate of who can assert harder. You give no numbers except incorrect assertions of ‘less and more’. You fail to back your claims. So publish your paper and it will end up in the stack with all the other Einstein deniers out there. They even hold Einstein-denial conventions due to the sheer volume of people that want to do this. Speeches are given of how Sagnac effect (predicted by STR) proves that STR is wrong. Everybody cheers. The world goes on unperturbed.
Sorry, but I’m getting tired of being asked for help that is not wanted.
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I did want your input, and it's been very useful. I have to thank you for putting in the time you have on it, and I'm getting much more useful feedback from you than from anywhere else, which reveals a lot about your quality. There's a reason why I've always rated you highly, regardless of how much we disagree about things. You have advanced this considerably.
Thanks for that, but from your replies, it very much appears that my remarks are being ignored. You repeat the same mistakes over and over.
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{I} isn't the one I'm calling weird.
Yes it is. I quoted your labeling of {I} as ‘weird’, here again:
It appears to me that you're dragging in some weird coordinate system which makes out that things are at a constant separation
You set things up to be constant separation under inertial coordinates in your paper, and then name that very coordinate system 'weird' in bold above. You verify this constant separation by regular measurement of round trip time, which only works in {I}. No claim is make by either of us that {I} is ‘actual’. It is {C} that LET assigned the metaphysical status of ‘actual’. The separation under {C} as you have set it up in your paper is not constant under {C}, so not ‘actually’ fixed separation, as you say. I illustrated that with my example numbers, which you did not contest.
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The weird CS is your {C} which makes out that constant separations as aren't constant.
OK, so your actual coordinates are ‘weird’ now. You certainly are not familiar with the properties of such a CS, so your finding it weird comes as little surprise. You switched sides on your designation of ‘exotic’ as well. Yes, LET would say that the actual separation is not constant the way you’ve set things up. The clocks are moving apart, as you should expect. I’ve repeatedly explained why this should be intuitive.
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Quote from: Halc
I gave a clear example that shows the length changing.
I couldn't work out what you were doing with it.
Then ask. You said you seek understanding, and it is best had by working through some real numbers. My fixed proper inertial length of the granite slab was 4.95, but under {C} (with one end ‘stationary’) it started out at 2.3 and steadily increases in length, approaching but never reaching 4.95. Anyway, a separation in {C} of 2.3 growing to nearly 5 seemed to be a fairly clear example of the separation distance significantly changing.
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Inertial coordinates are absolutely applicable to a test of STR such as this experiment.
Only if the experiment takes place in Minkowskian spacetime. In reality, gravity and dark energy render STR inapplicable except locally. If you assert otherwise, STR can be easily disproved by dropping a rock on your foot. STR says that relative to the inertial frame of Earth, if you let go of the rock, it should hover.  Isn’t that a lot easier empirical test than all this expensive complication you suggest? Trivial test, and you can claim victory.
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Where have you got changing separation?
My example started with a separation (as measured by an inertial slab of granite) of 2.3 which approaches 4.95 over time. This should be intuitive for you. I’ll try to word it in terms you seem to understand: Part of any really long object like that is going to have significant absolute motion due to ‘space’ whizzing by it, so it will be length contracted. As that absolute motion slows down (all without any proper acceleration), that contraction goes away with contraction backing off, but it never achieves its full length. It only approaches it after indefinite time.
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In an example where the outer clocks are in distant galaxies but are moving through them at speeds such that they maintain distance from the middle clock, they clearly have constant separation.
No CS reference, so the statement is not even wrong. They maintain distance only in inertial coordinates, as you specified. Don’t omit that very important detail, because ‘actual’ separation (as you define it) is not being maintained. You didn’t set it up that way. You were quite clear about using the standard inertial definition of constant separation.
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The granite slab wasn’t enough?
I never used one. No practical experiment of any size can.
It’s a thought experiment. There is no practical experiment until step 3, and you’re stuck in step 1 still. Only in step 3 do practical considerations come into play. You’re evading the issue seemingly to maintain a blind eye to any flaw in your guesses, perhaps because you think of this as a contest instead of an opportunity to learn. Change the attitude.
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Signals enable adjustments to maintain separation.
Again, it’s a thought experiment. These things are set up to be stationary relative to some inertial frame, so nothing is going to move them per Newton’s first law. I put in the granite to emphasize that, but it isn’t necessary since it applies no force to anything. It just acts as a solid tape measure. Any adjustments are external force. If external force is applied to our system, it would invalidate any time discrepancy measured since STR would simply say the distance changed due to your application of external force to things. Your goal seemed to be to take down STR.
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Why have you got the slab slowing down if the central clock is at rest?
Relative to cosmological {C} coordinates, if the one end of the slab is stationary, the other end must have some nonzero peculiar velocity (absolute motion as you put it), and that peculiar velocity decreases over time. If you look at my numbers, I picked an insane separation where the far end of the granite has peculiar velocity of .98c and is locally contracted in those coordinates by a factor of about 5.
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However, if I missed something about the middle clock not being the one at rest
I just have one end stationary and the other end moving. I found nothing additional illustrated by mirroring it in the other direction
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… while the observer at the middle clock gets the bounced back signals returning to him at a lower frequency than they were sent out from there, and he also sees the outer clocks get smaller: there is no length contraction change for him to cancel out that sight of them moving away.
No clock appears to get smaller over time. Also, any reflected signal comes back at the same frequency as it went out, not redshifted. Apparent size change and redshift are both effects of changing inertial distance in {I}, not in {C}, your ‘actual’ coordinates. The separation in {I} is not changing so no apparent size or frequency shift. The apparent size thing is admittedly not intuitive, and was something I had to work out myself during those several days I took to get self-consistent numbers.
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Shifting then to a case where the middle clock is moving
To do that, all I do is consider measurements made at the moving end. They should both measure the exact same thing. All metaphysical effects are completely masked, since the only difference is choice of abstract coordinates. You claim otherwise, but only because you’re not working with numbers, and I cannot point out errors when your numbers are just guesses of ‘more and less’.
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They’ll stay at a fixed distance relative to {I} if they start that way and no external forces act on them.
Not in the new version. They have ion drives or gas jets and actively adjust their speed to maintain a constant perceived beep rate from the central clock.
If you’re applying proper acceleration like that, the {I} separation and the measured round trip time with it. Why would you want to do that? The round trip time will be fixed if you don’t mess with their inertial motion. Both interpretations predict this. It’s an empirical thing, not a metaphysical assertion.
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I'm picturing them in the same way. To maintain the expansion rate you actively have to accelerate each little tube as it moves away from where it set out
The tubes (representing aether) don’t accelerate. In {I} any given tube moves at constant speed relative to any inertial frame. In {C} they’re all stationary. No acceleration of aether in either case. Dark energy does that, but working that in is part of priority 2, and you’re still working out the special case.
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That suggests to me that there will be no slowing of the content of the universe through space, so if the galaxies had all started out moving in the same direction through space at relativistic speed, they'll still be doing so.
You’ve seemed to have regressed. You’re back to asserting that peculiar velocity of an object is maintained in the absence of external forces on it? I really cannot help you then. Do a little research on your own for once. Do it on a decent site, and not a denier site.
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We are using {I} even though we're talking about space expanding.
That’s mixing coordinates. Of course you get nonsense then. If you’re taking about expanding space, that’s {C}. Use it. Don’t mix. It why I keep asking for frame references, but your biases somehow convince you that you can talk about both in the same sentence.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 13/06/2021 04:44:25
[Character limit hit, so two parts. First part is mostly the pantomime section]:-

It is becoming more clear that you have no desire to learn anything,...

My only concern is with correcting mistakes in science and stopping the propagation of misinformation and suppression of corrections. Here we have a broken STR being propped up even though it's clearly been blown out of the water repeatedly. You yourself have helped to that by showing how things slow down until they are at rest in space, which goes directly against the claims of STR. You then try to make out that STR doesn't make claims about there being no such thing as at rest, but you only manage that by ignoring the dogma that prevents it from being LET.

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But the continued unbacked and unquantified assertions seem to be your only tactic, and there seems to be no point in endlessly repeating how those assumptions are merely just that.

What I see time and time again from you looks like deliberate "misunderstanding" as an act of attempted sabotage. Despite that though, many of your contributions are still highly valuable, so I don't complain.

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... we never use a {C} frame at all.
You use it all the time, anytime you use the word ‘actual’. You assert that the far clock lags the (assumed) stationary near clock, which it doesn’t relative to {I}, but only relative to {C}. To say you never use {C} is to deny your favorite coordinate system.

There are two levels to this and you keep mixing them up. The experiment is described and carried out using {I} and not {C}. The comments layered over that use words like "at rest", "actual" and so on at a higher level in which you're being filled in on information that it not known to the observer setting up and running the experiment.

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It isn't at all baffling. We are using {I} frames while also recognising that space is expanding
No. Expansion is a coordinate effect, and thus it isn’t expanding under {I}, only {C}.

[Lower level]: We are using {I} frames [higher level]: while also recognising that space is expanding. The higher level is the meta: the intelligent understanding beyond the simple experiment.

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Calling aether ‘space’ is misuse of an abstract term

You know full well what I mean by space. I'm talking about a space fabric because that's what space has to be in order to provide the services which light depends on to have a speed and for it to have distances to cross at that speed.

And all that stuff from you about constant distances in {I} not being constant in {C} was incorrect too, by the way. If a distance is constant in {I}, it's necessarily constant in {C}. That caused a lot of confusion. What you were calling {I} on all those occasions was not {I} at all because you were actually using decelerating frames instead of {I} and failing to declare that. That's what led to me calling your {C} weird because your way of relating it to {I} was incompatible with physics. And having caused endless confusion and accusing me of causing it, you used your own sabotage to justify moving this to the under-the-carpet forum. I can't click "thank you" on posts that contain lots of sabotage and diversions, but I will continue to stick to thanking you for specific things where you have been helpful, and the biggest one of those is that the whole idea of things slowing down in expanding space until they are at rest, because that is something I had never considered as it is automatically a rejection of STR in our universe.

Incidentally, I found a mistake in the two key paragraphs in my last post: because the middle clock is slowing, the angles that things appear to be at as viewed from there changes, so the outer clock that's getting nearer could look as if it's getting further away, while the other outer clock that's getting further away could look as if it's getting nearer, so the parts about how it appears should be disregarded. The bit about the rod stretching out to the clock that's at rest though still appears to evade the masking: the slowing of the middle clock will lead to lengthening of most of that rod, and the strongest lengthening will be at the end connecting to the middle clock. Any shortening of it will happen beyond the outer clock, so the rod will extend beyond the outer clock as the outer clock continues to reduce the distance to the middle clock. A rod going the opposite way to the other outer clock would lengthen along its whole length, so it might keep up with or overtake that clock even though that clock is moving away. (In the alternative scenario though where the middle clock is at rest, there would be no change in the length of the rods at all and both the outer clocks would move away from the middle clock.)

That is what the discussion should be focusing on: the question as to whether there is an error leading to these different predictions for the outcomes of the two scenarios. If not, then the experiment can pin down absolute speeds in cases with things decelerated by the expansion of space, and that's something I've only considered because of your input: you have been crucial to this. If you find it all holds up and you decide you want your name on the paper too, I'd be happy to put it there.

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It simply means that light can't actually be moving at c
See? There’s that {C} reference.

Meta. Stop trying to mix the two levels together. The way to set up and run the experiment is all done using {I}, or what appears to be {I} to the experimenter - if the middle clock is decelerating due to the expansion of space, it is not genuine {I}, but again that possibility is part of the meta.

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There is zero empirical difference between the interpretations except apparently what it’s like to fall into a black hole.

The predictions about the results differ depending on whether the middle clock is actually at rest or is moving. In one case the outer clocks move away from the end of the rods (outwards), while in the other case we have one of the clocks moving inwards from the end of the rod on that side. The middle clock decelerates and so the rod lengthens while the outer clock has to reduce the separation between it and the middle clock. At the moment, that's the only clear difference we have between the two without working out specific numbers, but we can already tell that all parts of the rod between the outer clock and middle clock will be lengthening while the separation between those clocks reduces).

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We are testing STR against LET with an experiment where {I} frames are used at all times.
Then you will get {I} results in both theories,

Except (meta) you don't in an expanding space. The experiment is done with only {I} in mind and you get different results with the same apparatus set up the same way but with different sets of the apparatus moving relative to each other along the same straight line they operate on. Perhaps I could go through it colour coding it so that you can tell what's meta and what's the experiment, but I don't believe for a minute that you really need that.

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I’m trying to show you how LET does not predict different measurements. Relativity supports {C} just as much as LET, but without the metaphysics. So some amateur comes in with a demonstrable misunderstanding of the mathematics, and thinks he’s spotted an inconsistency between two different abstract choices of event ordering and will not listen to corrections on his misconception.

I've already demonstrated with the clocks, watches and miniwatches made near the time of the big bang that they reveal clear information about their absolute speeds when they pass each other. That disproves STR in an expanding universe right from the start and there's no misunderstanding on my part about such a discovery. The challenge from there was to try to replicate something of that today in expanding space, and that has led to a series of improvements to an experiment which still appears to be holding up by showing that there would be different results depending on whether the middle clock is at rest or moving. If there is a demonstrable misunderstanding the remaining crucial part, you have yet to demonstrate it. The end of the rod goes one way while the clock goes the other.

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You fail to back your claims.

On the contrary, I prove them, but you reject them because you don't want them to be right.

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Sorry, but I’m getting tired of being asked for help that is not wanted.

I'm grateful for all the actual help you've provided.

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Thanks for that, but from your replies, it very much appears that my remarks are being ignored. You repeat the same mistakes over and over.

You think you don't? What's this:-

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{I} isn't the one I'm calling weird.
Yes it is. I quoted your labeling of {I} as ‘weird’, here again:
It appears to me that you're dragging in some weird coordinate system which makes out that things are at a constant separation

That was a reference to your {C} and you've cut it down from this: "It appears to me that you're dragging in some weird coordinate system which makes out that things are at a constant separation when they're actually changing their separation and where constant travel times are asserted to vary too." No amount of quoting that or parts of it will turn it into a description of {I}. You misinterpreted that and then accused me of being inconsistent, and that bit about "inconsistent" reveals that you should have been alert to the likelity that you were misinterpreting something badly.

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You set things up to be constant separation under inertial coordinates in your paper, and then name that very coordinate system 'weird' in bold above.

And now you're repeating your misunderstanding of what something means. As I pointed out last time, my description there only fits {C} because of the word "actually". I made it abundantly clear that I was talking about {C} being weird based on your incorrect claims about it. From earlier in the same post I said "Constant separation is constant separation. If you're using some kind of coordinate system in which the coordinates keep changing for two objects that are at a constant actual separation from each other, then that could lead you to think of diverging points with constant coordinates being constant separation, but that isn't constant separation." The bit you keep quoting refers back directly to this. All the evidence is still there for all to see. You misinterpreted it and you continue to do so after being told not to misinterpret it.

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You verify this constant separation by regular measurement of round trip time, which only works in {I}. No claim is make by either of us that {I} is ‘actual’.

If it's constant in a genuine {I}, it's constant in {C}. That was where you slipped up and caused a lot of confusion, leading to me referring to your {C} as weird. You were using an apparent {I} rather than a genuine one, but I now know why you make such mistakes because you're incapable of looking at an apparent {I} and recognising that it is not an {I} because it is an accelerating frame with no acceleration force.

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It is {C} that LET assigned the metaphysical status of ‘actual’.

LET can call things actual while referring to {I}.

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The separation under {C} as you have set it up in your paper is not constant under {C}, so not ‘actually’ fixed separation, as you say. I illustrated that with my example numbers, which you did not contest.

Incorrect. The separations in my paper are constant in {I} and in {C}. I couldn't make sense of your numbers. I was going to ask for further explanation, but there's never been time because all your diversions have got in the way, and the bit about the clocks having to move faster than the speed of light then suggested that you were doing something totally irrelevant with them anyway.

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The weird CS is your {C} which makes out that constant separations as aren't constant.
OK, so your actual coordinates are ‘weird’ now. You certainly are not familiar with the properties of such a CS, so your finding it weird comes as little surprise. You switched sides on your designation of ‘exotic’ as well.

No - you provided misleading statements about constant separations in {I} not being constant in {C} and I consistently called your {C} weird as a result, not realising that your {I} was an accelerating frame and that you'd failed to label it correctly. That was the root of that whole problem.

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Yes, LET would say that the actual separation is not constant the way you’ve set things up. The clocks are moving apart, as you should expect. I’ve repeatedly explained why this should be intuitive.

In the cases where they are constant in {I}, they are also constant in {C} and the clocks are not moving apart. It took me a long time to realise why you were making the mistake of asserting otherwise.

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Then ask.

I was planning to, but all this other stuff you keep dragging up and warping gets in the way.

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You said you seek understanding, and it is best had by working through some real numbers. My fixed proper inertial length of the granite slab was 4.95, but under {C} (with one end ‘stationary’) it started out at 2.3 and steadily increases in length, approaching but never reaching 4.95. Anyway, a separation in {C} of 2.3 growing to nearly 5 seemed to be a fairly clear example of the separation distance significantly changing.

I didn't realise back then that you had one end stationary rather than the middle clock, which is why it looked like nonsense. Here's the original version:-

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{I}: When both clocks reads T=5.05 (age of universe if you will, and you said the clocks were to be in sync relative to {I}) and the length of our stationary granite slab being 4.95 light-units, a signal sent from the far end would be measured at T=10 at the center clock. I didn’t bother putting a 2nd object in the opposite direction.
Same scenario using {C}: The light is emitted at time T=1 from our far clock (It reads 5.05 because the clocks are not in sync in {C}) moving at a peculiar velocity of .98c towards us from a distance of 2.3 units.  It takes 9 units of time to reach the center clock.  The distance to the far emitting object is 2.3 and growing over time. There is no way any object can be there and maintain that 2.3 separation distance. Constant separation relative to a stationary object in {C} can only be maintained at peculiar velocities of about 0.76c and below. A clock at the end of the granite slab ticks once per dilated second and those ticks will be measured at the origin at one per second starting at time 10.

Your {I} was not {I}, but {A}. There is no way that the separation in {C} can grow with a constant separation in {I}, so I thought you were making some huge error that was preventing you from making the outer clocks move in such a way to maintain separation from the middle one which I thought was supposed to be at rest.

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In reality, gravity and dark energy render STR inapplicable except locally.

If it's gone in any of those ways, it's gone locally too: it misdescribes what is physically happening.

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Part of any really long object like that is going to have significant absolute motion due to ‘space’ whizzing by it, so it will be length contracted.

Length contracted things in a genuine {I} are the same length in {C} where they remain contracted.

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As that absolute motion slows down (all without any proper acceleration)

It is still a deceleration and is not {I}. The object is seen to decelerate in a genuine {I}.

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In an example where the outer clocks are in distant galaxies but are moving through them at speeds such that they maintain distance from the middle clock, they clearly have constant separation.
No CS reference, so the statement is not even wrong. They maintain distance only in inertial coordinates, as you specified. Don’t omit that very important detail, because ‘actual’ separation (as you define it) is not being maintained. You didn’t set it up that way. You were quite clear about using the standard inertial definition of constant separation.

Here again, I was referring to a genuine {I} while you were using a fake one which should be called {A}. The problem is that we've been understanding {I} differently with you sneaking accelerated frames in along with the genuinely inertial ones.

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You’re evading the issue seemingly to maintain a blind eye to any flaw in your guesses, perhaps because you think of this as a contest instead of an opportunity to learn. Change the attitude.

I'm not the one evading things: you were pretending not to understand how signals can be used to maintain constant distances.

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Any adjustments are external force. If external force is applied to our system, it would invalidate any time discrepancy measured since STR would simply say the distance changed due to your application of external force to things. Your goal seemed to be to take down STR.

Not so. Accelerations don't have that effect when they're used to keep an object at a precise speed and you're using them to cancel out the accelerations caused by gravity which would otherwise disrupting the separation distances. It's by making these adjustments that you avoid the clock ticking slowly due to added speed accumulating. A lot of that is also to make sideways adjustments to stop the clocks moving off the straight line.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 13/06/2021 04:46:27
Part 2:-

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No clock appears to get smaller over time.

They do, because in the case when the middle clock is at rest, the two outer clocks are moving away from it and the length contraction on the middle clock and its view of the action does not undergo any contraction at any time. The outer clocks are both ticking more slowly and have to move further away from the middle clock continually, so they will be seen to get smaller.

Now, when the middle clock isn't the one that's at rest and if you can manage to contrive there to be total masking of the difference, then both outer clocks must be seen to move further away in all runnings of the experiment. Also, if you have a rod sticking out to the outer clocks from that middle clock when it's at rest, that rod will not extend to keep the tips at the outer clocks: they will move away from the rods. The same would have to happen in all runnings of the experiment for there to be total masking, but that doesn't look possible in the case where one of the outer clocks is the one at rest. It has to move towards the central clock, while the deceleration of the central clock leads to the entire rod between the middle clock and the one that is initially at rest losing some length contraction and thereby becoming longer with the tip moving further away from the middle clock than the clock that was initially at rest.

And all of that can be worked out and demonstrated just by using the numbers more and less (or words equivalent to them). You can make the deceleration any value you like and you can choose any value you like for the middle clock's speed: the description will fit all such cases. That is the power of using these special numbers in mathematics, and it's the way mathematicians think before the resort to the calculator, leading to them very rarely needing to pick one up when exploring things like this.

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Also, any reflected signal comes back at the same frequency as it went out, not redshifted.

We're using frequency of arrival of beeps. If the middle clock is decelerating, that will affect the times taken for the beeps to cross the divides between clocks, but in the version where that's happening, all we depend on is that the outer clock keeps positioning itself to receive the beeps at the right times, so when the middle clock decelerates, the outer clock decelerates accordingly while continuing to get closer to it, which it must do because it is still ticking faster than the middle clock. For example, if the middle clock's moving at 0.866c and ticking half as often as the outer clock, a deceleration of the middle clock to 0.8c would still leave it ticking 0.6 times as often as the outer clock if it wasn't closing the gap, so the outer clock still has to race into the signal while the rod extends to a greater length in the opposite direction. That's a difference that isn't being masked, and unless I've made some big mistake in this analysis, it shows that no one's ever worked through this adequately before.

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Shifting then to a case where the middle clock is moving
To do that, all I do is consider measurements made at the moving end. They should both measure the exact same thing. All metaphysical effects are completely masked, since the only difference is choice of abstract coordinates. You claim otherwise, but only because you’re not working with numbers, and I cannot point out errors when your numbers are just guesses of ‘more and less’.

On the contrary, I've given you a description using numbers like "more" and "less" which tightly locks things down. The middle clock decelerates and ticks faster, but the outer clock is still ticking faster than it and must still be getting closer to it to maintain the required perceived beep rate while the rod must be losing contraction over most of its length. The tip of it will have started to contract again as it extends out beyond the place where part of the rod is at rest: that point that's at rest is also moving towards the middle clock, but the outer clock is moving towards the middle clock faster than the at-rest point with the entire part of the rod between the two clocks losing contraction, and doing massively more quickly at the middle-clock end than in the part beyond the at-rest part, so the increase in length of the part of the rod that's losing contraction is having a bigger effect on the total length of the rod than the addition of new contraction to the part between the at-rest end and the tip leading to the total length of the rod growing until the at-rest point is half way along it, and it'll take a long time for it to get that far, while the outer clock is always ahead of the at-rest point, nearer the middle clock.

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They have ion drives or gas jets and actively adjust their speed to maintain a constant perceived beep rate from the central clock.
If you’re applying proper acceleration like that, the {I} separation and the measured round trip time with it. Why would you want to do that? The round trip time will be fixed if you don’t mess with their inertial motion. Both interpretations predict this. It’s an empirical thing, not a metaphysical assertion.

It's only the outer clocks that do this. The middle clock is always allowed to drift (though with a box around it which can adjust position to prevent dust or gas accelerating the clock - if the box is pushed towards the clock, the box moves back to restore its position relative to the clock). The outer clocks have to be able to accelerate in order to travel at whatever speed they have to to maintain the required perceived beep arrival rate. Remember that this is the newer version of the experiment in which separations are not kept constant. The original maintaining of constant separations was too slow to adjust as any adjustments applied would be delayed by a whole round trip and a half of a signal to measure the drift that needed to be corrected (it had to be measured by the central clock) and then to relay the need for correction to an outer clock. The new version eliminated that issue by having instant reactions to the arrival of signals instead where there could be no error in where the signal was when it was meant to be encountered. That's why I shifted to clocks moving along the line trying to maintain a constant percieved beep arrival rate.

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The tubes (representing aether) don’t accelerate. In {I} any given tube moves at constant speed relative to any inertial frame. In {C} they’re all stationary. No acceleration of aether in either case. Dark energy does that, but working that in is part of priority 2, and you’re still working out the special case.

Were the expansion of space occurs at a constant rate, the tubes have to accelerate to maintain that. The following represents a set of tubes. You should imagine the "*" as a roller sitting on whichever tube is directly below it:-

xxxxxxxxxxxxxxxx---------------*
--------yyyyyyyyyyyyyyyy
----------------zzzzzzzzzzzzzzzz

xxxxxxxxxxxxxxxx---------------*
----------------yyyyyyyyyyyyyyyy
--------------------------------zzzzzzzzzzzzzzzz


If we have telescoped tubes extending like this, the space from the left-most x to the * is expanding more than it will expand after the same length of time because the y tube is moving more slowly than the x tube. That model results in a continual decrease in the expansion rate of the local space and causes the roller to go round more slowly. If the tubes are accelerated though to keep the expansion rate constant, the roller will rotate at a constant rate.

Another way to do it would be to start with xxyyzz with the roller on the second z, then add another x, y and z to extend it to xxxyyyzzz with the roller on the third y, then xxxxyyyyzzzz, and by the third one of these have the roller over the second y. When we get to xxxxxxyyyyyyzzzzzz we have the roller over the over the last x, but we're adding x's in more often as things go on, so the roller is still going round at the same rate and the local space is expanding at a constant rate.

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You’ve seemed to have regressed. You’re back to asserting that peculiar velocity of an object is maintained in the absence of external forces on it? I really cannot help you then. Do a little research on your own for once. Do it on a decent site, and not a denier site.

I'm not rejecting your idea that things slow down in expanding space. I'm just covering both possibilities because I'm not convinced that you're right and it's important to consider all possibilities. You asked me why I think the roller will rotate at a constant rate with the pipes, and I've shown you: if you don't add more pipes and accelerate the existing ones, the expansion of the local space slows down, whereas if you maintain that expansion rate instead, the roller keeps rotating at a constant rate. When light is redshifted by expansion of space, there must be new space created inside the light which is spread out and not all at a point. If you imagine an object made of two parts, new space could appear between them, and then they'll pull back to their original separation. If the object's at rest, that will not change the speed of the object, and I don't see why that should be any different for a moving object because no force is applied by the insertion of new space, but maybe something does apply a force to slow the object a little. I'm fully open to that possibility, but what evidence do you have for it? How do you know that the galaxies weren't all moving at some speed at the outset and still are doing so at that same speed? The result would look identical. Now, you might be happy to make assumptions, but I'm not. I see two possibilities and both need to be considered. If your one is the right one, that's fine: it demonstrates the existence of absolute speeds, and my experiment would confirm it independently (if there isn't total masking). If you're wrong, then my experiment may produce a different answer about how fast things are moving. That's how science is supposed to be done.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 14/06/2021 16:30:11
My only concern is with correcting mistakes in science and stopping the propagation of misinformation
Precisely what I’m trying to do, but the purveyors of the misinformation has a deaf ear to having self-contradictions pointed out.
What I see time and time again from you looks like deliberate "misunderstanding" as an act of attempted sabotage. So talk to the numbers. Numbers don’t lie.
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You yourself have helped to that by showing how things slow down until they are at rest in space
Space (and ‘at rest’) is a CS dependent value, and sans CS reference, your assertions are not even wrong. I said no such thing. I would not have made such an unqualified statement. So you’re misrepresenting my words, which is typical.
However much you think I should be able to glean the CS from the context, I cannot ever agree to such ambiguous statements as you will misuse such quotes against me, as you are attempting to do right there.
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There are two levels to this and you keep mixing them up. The experiment is described and carried out using {I} and not {C}.
The specification of the setup is done using values (separation distance for instance) as measured in {I}. It is carried out in all coordinate systems because at least locally, one cannot be out of a coordinate system. For instance, the measurement of the round trip signal time, being empirical, is a CS independent fact, and thus is predicted in both coordinate systems. If they’re not, then one of the coordinate systems is not self-consistent. Such seems to be your claim, but the discrepancy is due to your misapplication (or complete lack of) of the mathematics of sometimes both CSs.
You’ve not pointed out where I keep ‘mixing up’ two levels. Be specific. Level 1 seems to be choice of CS, which you rarely specify. Level to seems to be CS dependent relations like ‘at rest’, which are meaningful in my comments precisely because I remember my CS references
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[Lower level]: We are using {I} frames [higher level]: while also recognising that space is expanding.
That is a deliberate misrepresentation of the mathematics. If we’re using {I} frames, then space is not expanding. It’s simply not a property of inertial frames.Yet again, ‘space’ is an abstract mathematical CS dependent value. It isn’t a physical thing. Any reference to some metaphysical asserted thing needs a different word like aether or something. I can accept a statement that we can use {I} while aether is expanding within it, resulting is less aether between the ends maintaining fixed space between them. This is all part of being clear.
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The higher level is the meta: the intelligent understanding beyond the simple experiment.
But you’re using abstract terms to mean something meta. If you posit a metaphysical thing, give it a different name than the word that already has a mathematical and very CS dependent meaning.
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You know full well what I mean by space.
No. Space has a defined meaning, and to change that meaning is to deliberately obfuscate things. You don’t have to use aether if you think it is offensive. But use something not already defined otherwise. The goal is communication here, and overloading existing terms does not help with that. These posts are so long because I spend ¾ of the space harping on being clear about the CS references, and you making all these assertions that are meaningless without them.
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I'm talking about a space fabric
Excellent. Include the word ‘fabric’ every time you mean that, and I’ll know it is a {C} reference. That isn’t a pre-defined mathematical term. You can also say ‘absolute rest’, which is enough to define a {C} reference, but only because you claim {C} to be absolute, not because {C} itself has any necessary metaphysical properties. But just ‘at rest’ is meaningless without a CS reference.
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And all that stuff from you about constant distances in {I} not being constant in {C} was incorrect too, by the way. If a distance is constant in {I}, it's necessarily constant in {C}.
The numbers say otherwise. Numbers don’t lie. Unbacked assertions do. You’re essentially asserting that a moving rod is necessarily not length contracted, which is nonsense.
In my example, relative to {I}, the separation space is deliberately set up at a constant 4.95, and at no time is a different value. Signal time is a constant 4.95 in each direction.
Relative to {C}, the separation at time 1 is about 2.3, at time 5.05 it grows to 4.38 and at time 10 it has reached 4.77. The peculiar velocity of the moving clock is at those respective times 0.98c, 0.7c, and 0.44c all in the direction of the stationary clock, so always slowing as should any inertial object. A signal emitted at time 1 from the moving end takes 9 units to reach the stationary clock at time 10. Any reflected signal takes significantly less than that for the return trip despite the growing separation between the clocks.
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That caused a lot of confusion. What you were calling {I} on all those occasions was not {I} at all
I meant what I wrote. If I made a mistake, which is reasonably likely, I’ll admit it if it is quoted to me, but DO NOT put words in my mouth. If I said {I}, then I meant as measured by inertial coordinates where the one clock is stationary.
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light can't actually be moving at c
Light moves at c in both coordinate systems. It will be measured at c relative to any frame in {I}, and constant peculiar velocity in {C}.
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The predictions about the [empirical] results differ
I’m well aware of your persistent assertions, but the numbers don’t lie.
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I've already demonstrated with the clocks, watches and miniwatches made near the time of the big bang that they reveal clear information about their absolute speeds when they pass each other.
That can be done by clocks released from any event, not necessarily the big bang. If you do it right now from Earth, the exact same measurements will be had. In the absence of energy density (positive or negative), expanding space is just a coordinate system relative to an event. So your demonstration doesn’t distinguish expanding metaphysical aether from inertial aether since the same experiment with the miniwatches can be done with either metaphysics, and the empirical result is unaffected. Empirical results are never affected by metaphysical premises because if they were, they wouldn’t be metaphysical.
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On the contrary, I prove them, but you reject them because you don't want them to be right.
And yet my numbers demonstrate my case and the lack of your numbers condemns your case. Numbers don’t lie.
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I made it abundantly clear that I was talking about {C} being weird
Fine. {C} is weird to you. My condolences. You’ve asserted that one to be the absolute one, but you seem oblivious to the properties of such a CS, so it is little surprise to me that you admit to finding it ‘weird’.
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If it's constant in a genuine {I}
I don’t think ‘genuine’ is a physics term. Sounds like a philosophical distinction, completely irrelevant to empirical physics. If it has empirical meaning, then state it. Otherwise the label is a decoration. I don’t care about philosophy, and your experiment doesn’t have a ‘genuine’ meter to monitor. I’m only using your philosophical terminology to occasionally identify CS when you consistently fail to be explicit about it. I have no other use for what you assert to be more real than something else.
Do not interpret any of my words to be references to genuine or actual things. I reference {I} or {C} explicitly, and I mean relative to the one I indicate. If I say that separation distance is constant, I’m referring to coordinate separation using the CS specified. I’m never making any references to metaphysical woo. Any unmeasurable metaphysical properties asserted are not my concern.
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The separations in my paper are constant in {I} and in {C}.
I don’t recall the assertion in the paper, but the assertion here demonstrates your ignorance of basic hyperbolic coordinate properties.
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he bit about the clocks having to move faster than the speed of light then suggested that you were doing something totally irrelevant with them anyway.
It is completely relevant since it involves a scenario with inability to maintain constant separation in {C}. Perhaps it doesn’t make sense due to your lack of familiarity with hyperbolic coordinates. For instance, GN-z11 (a galaxy with redshift of z=~11) is around 32 BLY distant (proper distance along constant time) and receding at a rate of about 2.3c. This is using {C}, about the only CS used by anybody to describe such distant things. Max peculiar velocity is almost c, so there is no way for a clock there to maintain constant separation with the Earth clock even if that clock was fired at nearly c towards this distant clock. So I’m not doing something irrelevant. I’m trying to demonstrate some properties of the CS that you assert to be absolute.
This is what I mean by asking rather than ignoring the numbers that seem to scare you.
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you provided misleading statements about constant separations in {I} not being constant in {C}
Quote me please. Yes, I stand by any remark about the constant separatuion, but I’m wondering why you’re designating it as misleading. I’m trying to correct a critical mistake you’re making.
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not realising that your {I} was an accelerating frame
An accelerating frame is not inertial, so is not an {I} frame. This is your attempt to strawman a very basic coordinate system. My {I} is not accelerating. No forces act on the stationary clocks, which is why they maintain their constant separation.
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Then ask.
I was planning to, but all this other stuff you keep dragging up and warping gets in the way.
I will make a point to limit my responses to assertions without numbers. Helps keep the replies shorter at least.
Then stop it with the assertions and post questions about the numbers. Assertions are not going to demonstrate me wrong.
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I didn't realise back then that you had one end stationary rather than the middle clock, which is why it looked like nonsense. Here's the original version:-
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{I}: When both clocks reads T=5.05 (age of universe if you will, and you said the clocks were to be in sync relative to {I}) and the length of our stationary granite slab being 4.95 light-units, a signal sent from the far end would be measured at T=10 at the center clock. I didn’t bother putting a 2nd object in the opposite direction.
Same scenario using {C}: The light is emitted at time T=1 from our far clock (It reads 5.05 because the clocks are not in sync in {C}) moving at a peculiar velocity of .98c towards us from a distance of 2.3 units.  It takes 9 units of time to reach the center clock.  The distance to the far emitting object is 2.3 and growing over time. There is no way any object can be there and maintain that 2.3 separation distance. Constant separation relative to a stationary object in {C} can only be maintained at peculiar velocities of about 0.76c and below. A clock at the end of the granite slab ticks once per dilated second and those ticks will be measured at the origin at one per second starting at time 10.
You’re right. It wasn’t made clear that the near end was stationary in {C}. Wish you had pointed that out then instead of wasting all this time ignoring the one important thing.
I’ve since added a few new numbers above. The brief example isn’t exactly full of them.
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Your {I} was not {I}, but {A}.
I said inertial. There are no external forces, so no acceleration in {I}. {A} requires an external force to maintain proper acceleration, which would be empirically measured by an accelerometer. If you add accelerometers to the ends, they’ll all read zero.
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Accelerations don't have that effect when they're used to keep an object at a precise speed
Meaningless statement without CS ref. In {C}, keeping a moving object at a constant speed is different than keeping it at a constant separation relative to some stationary object. But proper acceleration (you don’t identify which kind of acceleration you mean) is required for both cases. Again, your statements lack numbers, and are consequently vague.
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in the case when the middle clock is at rest, the two outer clocks are moving away from it
You’ve repeatedly denied this. So now you’re contradicting yourself.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 15/06/2021 03:53:04
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You yourself have helped to that by showing how things slow down until they are at rest in space
Space (and ‘at rest’) is a CS dependent value, and sans CS reference, your assertions are not even wrong. I said no such thing.

Regardless of your protest, you showed that things slow down until they are at rest. That statement is not quoting what you said and is not an invitation for people to apply the wrong CS to it.

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For instance, the measurement of the round trip signal time, being empirical, is a CS independent fact, and thus is predicted in both coordinate systems. If they’re not, then one of the coordinate systems is not self-consistent. Such seems to be your claim, but the discrepancy is due to your misapplication (or complete lack of) of the mathematics of sometimes both CSs.

The discrepancy was down to your use of {I} for an accelerating frame.

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You’ve not pointed out where I keep ‘mixing up’ two levels. Be specific. Level 1 seems to be choice of CS, which you rarely specify. Level to seems to be CS dependent relations like ‘at rest’, which are meaningful in my comments precisely because I remember my CS references

Every time you claim to be confused about simple situations where I describe the action from the point of view of {I} (or what the person carrying out the experiment perceives as {I}), and then provide comments about what's actually going on in the real universe.

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[Lower level]: We are using {I} frames [higher level]: while also recognising that space is expanding.
That is a deliberate misrepresentation of the mathematics. If we’re using {I} frames, then space is not expanding. It’s simply not a property of inertial frames.

Nonsense. The experiment is being carried out by someone who needn't have any thought in his head about the expansion, and he's using what he calls {I}. Meanwhile, we are looking at the action and are fully aware that the space may actually be expanding: there is only one thing happening there as it can't both be expanding and not expanding at the same time. Far from being a misrepresentation of the mathematics, this the correct mathematical way to look at it. Some scientist carrying out the experiment who uses {I} for it does not stop the space expanding. And if you need to, you can add "fabric" to space every time I use the word without me having to write it because that's what space is in this context. When it expands, there is more of it. It is a stuff that governs the speed of light through itself, limiting it to c, and when that scientist who believes in STR is projecting his {I} frame onto it, his frame misrepresents the speeds that light is actually moving at in different parts of the space he's mapping it to. This is fundamental: if {C} is the reality and space is expanding, {I} is always false, though it can potentially be right for one location and the middle clock will be at that location if it is genuinely at rest (which obviously means in {C} which we are considering to be reality).

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If you posit a metaphysical thing, give it a different name than the word that already has a mathematical and very CS dependent meaning.

There's the actual universe, which is not a metaphysical thing, and there are also attempted descriptions of it such as {I} frames. The experiment runs on {I} frames (some of which are fake {I} as they're accelerating) while we discuss it in relation to what we think the universe may actually be doing. This isn't difficult to understand. Two clear levels: the naive one and the one discussing what might actually be going on.

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Space has a defined meaning, and to change that meaning is to deliberately obfuscate things.

Space has multiple meanings and I'm free to choose which one to use. I always prefer rational definitions, so if one frame represents a volume of space with no length contraction acting on it, another frame has that same volume of space contracted and moving through the frame. You prefer a magical definition which has that same space as two different spaces, but the universe only has one reality.

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These posts are so long because I spend ¾ of the space harping on being clear about the CS /references, and you making all these assertions that are meaningless without them.

The meanings are obvious if you understand that there is only one reality.

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And all that stuff from you about constant distances in {I} not being constant in {C} was incorrect too, by the way. If a distance is constant in {I}, it's necessarily constant in {C}.
The numbers say otherwise. Numbers don’t lie. Unbacked assertions do. You’re essentially asserting that a moving rod is necessarily not length contracted, which is nonsense.

You're using an accelerating frame for your example, so it isn't valid: you have it varying in C because the fake {I} is decelerating through an infinite series of real {I} frames which each give the object a different length which matches up to its length in {C} in each case.

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light can't actually be moving at c
Light moves at c in both coordinate systems. It will be measured at c relative to any frame in {I}, and constant peculiar velocity in {C}.

One of them can misrepresent the speed of light relative to the frame so it isn't actually moving at c relative to the frame in most cases of {I}: the frame merely represents it as moving at c relative to the frame.

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The predictions about the [empirical] results differ
I’m well aware of your persistent assertions, but the numbers don’t lie.

Indeed they don't lie, and they still appear to support what I said. The rod loses contraction while the trailing outer clock moves nearer to the middle clock, in the case where that outer clock is initially at rest (in {C}), while in the case where the middle clock is at rest (in {C} throughout, there is no change to any part of the rod's state of contraction at any time, while the outer clocks both move away. That's the crux of the matter.

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I've already demonstrated with the clocks, watches and miniwatches made near the time of the big bang that they reveal clear information about their absolute speeds when they pass each other.
That can be done by clocks released from any event, not necessarily the big bang. If you do it right now from Earth, the exact same measurements will be had.

It can't be done from the Earth in isolation: you won't have any of the watches and clocks meet up again because they'd all move away and never come back. The equivalent case if started today would need the co-operation of aliens in other galaxies all sending them out too, with them all doing so at the same time (in {C}). For us to do the experiment without such help (which will never come), we have to switch to other kinds of experiment.

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On the contrary, I prove them, but you reject them because you don't want them to be right.
And yet my numbers demonstrate my case and the lack of your numbers condemns your case. Numbers don’t lie.

Yet my numbers (and they most certainly are numbers in mathematics) demonstrate my case.

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I made it abundantly clear that I was talking about {C} being weird
Fine. {C} is weird to you. My condolences. You’ve asserted that one to be the absolute one, but you seem oblivious to the properties of such a CS, so it is little surprise to me that you admit to finding it ‘weird’.

The claims you were making made it seem weird, but it was actually your {I} that was weird because it was decelerating. After finding out what you were doing, I have no problem with your {C}.

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If it's constant in a genuine {I}
I don’t think ‘genuine’ is a physics term.

If the official vocabulary of physics is deficient, that is not my fault. There is a real universe and it is not a mere decoration.

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The separations in my paper are constant in {I} and in {C}.
I don’t recall the assertion in the paper, but the assertion here demonstrates your ignorance of basic hyperbolic coordinate properties.

In my paper I wasn't taking into account the decelerations that you say happen, so it was using {I} frames that behave differently from yours. That was the thing I didn't know about, and it's the thing that messes up the original version of the experiment because it makes it impossible to know if the separations are constant. Hence the shift to a version where the outer clocks move and just maintain a constant perceived rate of beep arrivals from the middle clock.That was your big contribution to this - you drove that change days ago, but it's taken you a long time to notice because you're still spending most of your time keeping arguments about an obsolete version going instead of switching attention to the key issue.

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not realising that your {I} was an accelerating frame
An accelerating frame is not inertial, so is not an {I} frame. This is your attempt to strawman a very basic coordinate system. My {I} is not accelerating. No forces act on the stationary clocks, which is why they maintain their constant separation.

That's exactly my point: it's not inertial, so it is not an {I} frame, although the scientist mistakes it for one. Your {I} is decelerating without any force being applied to it: it's doing so due to the expansion of space.

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Your {I} was not {I}, but {A}.
I said inertial. There are no external forces, so no acceleration in {I}. {A} requires an external force to maintain proper acceleration, which would be empirically measured by an accelerometer. If you add accelerometers to the ends, they’ll all read zero.

It is decelerating regardless. The difficulty here is that physics has a deficiency of vocabulary and labels for making crucial distinctions between different types of frame, and that's what's causing all the trouble. We need new labels for them, but you'll want to stick to the deficient range and will object to anything with greater semantic precision. Virtually all the pantomime content of these posts is driven by that conflict.

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in the case when the middle clock is at rest, the two outer clocks are moving away from it
You’ve repeatedly denied this. So now you’re contradicting yourself.

You must be misremembering something because, apart from when I initially inverted the directions of travel and pointed out in the next post that I had done so, I have always said that if the middle clock is at rest (in the newer version of the experiment) [it's always at rest in the {I} frame used by the person running the experiment, so that "if it's at rest" part refers to it being rest in {C}], then the outer clocks are ticking slower and must be moving away from the central clock in order to maintain the required perceived beep arrival rate, so no: I have never denied what you've just said I denied repeatedly, and the evidence for that is all up there in posts with dates (and which show when they were last modified if they have been modified).
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 15/06/2021 17:50:43
There's the actual universe, which is not a metaphysical thing
On the contrary, by definition, the actual universe is a metaphysical thing. This is a science site which concerns itself only with the empirical universe, which is a physical thing. We seem unable to communicate because you won’t talk empirical physics and you beg a metaphysical view which is far and gone from any metaphysical view I might find plausible.
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If the official vocabulary of physics is deficient, that is not my fault. There is a real universe and it is not a mere decoration.
Again, you’re confusing metaphyiscs (ontology, or assertions about what is real, or what is) with physics, which is about what is measured/observed.
For this thread, you propose an empirical falsification test, and thus it is the empirical universe we care about. Stick to that. I don’t think that you can. You seem utterly incapable. You call science ‘naive’ now, but that’s the level that your paper proposes a test.
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The rod loses contraction while the trailing outer clock moves nearer to the middle clock in the case where that outer clock is initially at rest (in {C}),
This statement seems self contradictory. Yay for the CS reference though. Regardless of which clock is stationary, how can the clocks move nearer to the middle if the rod to which they are all bolted is growing longer?
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while in the case where the middle clock is at rest (in {C} throughout, there is no change to any part of the rod's state of contraction at any time
Not true since the peculiar motion of the ends is always decreasing, and contraction in {C} is a function only of peculiar motion. You seem to have almost no familiarity with coordinate systems of this nature.

There seems to be no other discussion of actual physics in your last reply. You’ve ignored every number I posted, so I can only assume that they agree with your numbers. They illustrate all my points. Different numbers result in mathematical contradictions, a few of which I’ve pointed out.
I did say that per your request, I’d be limiting my responses to your philosophical assertions. Open a thread in just-chat for that, or better, on a proper philosophy site.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 16/06/2021 01:05:04
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The rod loses contraction while the trailing outer clock moves nearer to the middle clock in the case where that outer clock is initially at rest (in {C}),
This statement seems self contradictory. Yay for the CS reference though. Regardless of which clock is stationary, how can the clocks move nearer to the middle if the rod to which they are all bolted is growing longer?

Why are you trying to bolt it to anything? Fair enough to bolt the middle clock to the rod, but the outer clocks are required to move either towards or away from the middle clock (or stay still) in order to receive a perceived beep arrival rate from the middle clock of one beep per second. [I introduced the newer version of the experiment many posts ago and yet you're still trying to turn it back into the old, obsolete version in the paper.] We start with one of the outer clocks at rest {C} while the middle clock has space moving through it in the direction away from that outer clock, so the outer clock (we can ignore the other outer clock for now) is ticking faster than the middle clock and has to move towards it until it receives the required perceived beep arrival rate from the middle clock of one beep per second, and then it tries to maintain that by continuing to move towards the middle clock. If the middle clock somehow isn't decelerating in {C}, then the rod won't change length, but the outer clock will move along it, getting nearer to the middle clock while the tip of the rod stays a fixed distance from the middle clock. If you have the middle clock decelerating in {C} though (which is what you say must happen), then the rod will lengthen in addition to the outer clock moving along it, so we have the tip of the rod moving away from the middle clock while the outer clock moves nearer to the middle clock. Either way that's a measurable effect, and a very different one from the alternative situation in which the middle clock is at rest in {C}.

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while in the case where the middle clock is at rest (in {C} throughout, there is no change to any part of the rod's state of contraction at any time
Not true since the peculiar motion of the ends is always decreasing, and contraction in {C} is a function only of peculiar motion. You seem to have almost no familiarity with coordinate systems of this nature.

Again you completely fail to grasp the details of the experiment, the outer clocks are required to move either towards or away from the middle clock (or stay still) in order to receive a perceived beep arrival rate from the middle clock of one beep per second. Because they are ticking more slowly than the middle clock in this case where the middle clock is at rest in {C}, they must both continually move away from it, and do so forever, while the rod does not change its length (and no, they are absolutely not bolted to it in this version of the experiment).

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There seems to be no other discussion of actual physics in your last reply.

Everything's at a halt until you understand the actual experiment and stop trying to turn it back into the obsolete one in the paper. I don't know how many times I have to spell it out before you notice.

From reply #20 (where the idea for the new version appeared):-

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Of course, we want the middle clock to stay still, so it can't make instant adjustments to the positions of the outer clocks, so it would be better to have the outer clocks try to maintain exact one-second intervals in the timings, leading to them gradually moving closer to the central clock if they're ticking faster than it is or gradually moving further away from the central clock if they're ticking slower. The central clock would then be able to read the distances to them by how early or late the signals come back from them, and this would also be a measure of the relative ticking rates, so that then provides information about which of the clocks is/are moving through space fastest.

From reply #21

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Now, in the latest version I'm allowing the outer clocks to move relative to the middle clock in order to maintain the arrival of beeps at a constant rate of one beep per second as measured by the receiving clock, but STR won't allow them to move relative to each other at all in this situation with this experiment because it demands that they'll all be ticking at the same rate. The real universe though will allow those clocks to move if the local space between them is expanding, and at least one of them will move relative to another of the clocks, thereby revealing the existence of absolute speeds and enabling us to work out when things are at rest. As soon as we know what's at rest, we know that a clock that's at rest is ticking faster than a clock that moves past it and that this is not a symmetrical relationship where it's just as valid to say that the clock moving past it is ticking faster than the one that's at rest: that relativity has been lost and we've replaced it with absolutes.

From reply #23:-

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Of course I've established it. The new version's the one you should switch to as it makes it much easier to see that different measurements will be made in different cases. The emitting clock (my central one) plays the tune while the receiving clock(s) dance(s) to its tune. If the emitter is ticking slower than the receiver, the receiver must move towards it to hear what it measures as one beep per second. If the emitter is ticking faster than the receiver, the receiver must move away from it to hear what it measures as one beep per second.

From reply #25:-

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In the case with the middle clock at rest, the outer clocks are moving through space (with that space moving out past them away from the middle clock), leading to them ticking more slowly than the middle clock. That will lead to them both having to move away from the central clock in order to receive the required perceived ticking rate, though as they do this they will also reduce their speed through the space that's local to them, so that leads to their clocks ticking faster, thereby suppressing the extent to which they have to move away from the central clock, but they will still both continually move away from it, and the result of doing so will be that the experiment will stretch to a longer length through space and amplify the speed of movement of the outer clocks away from the middle one while the observer at the middle clock gets the bounced back signals returning to him at a lower frequency than they were sent out from there, and he also sees the outer clocks get smaller: there is no length contraction change for him to cancel out that sight of them moving away.

Shifting then to a case where the middle clock is moving through space but decelerating a little during the experiment due to the expansion of space, what happens now? At all times throughout the experiment it will be moving in a single direction, but the slight deceleration will result in its ticking rate increasing a little as the experiment runs. If we have one of the outer clocks at rest in its local space, then that outer clock is ticking at a faster rate than the middle clock, and in such a case, we have the central clock initially sitting with space moving out through it away from the outer clock that's at rest. We'll ignore the other outer clock for now and just call the clock that's initially at rest the outer clock. The middle clock is ticking slower than the outer clock, so the outer clock has to move towards it in order to maintain the required perceived beep arrival rate in the signal it's receiving from the middle clock, but as it does so, that movement leads to it ticking at a lower rate as it starts to move slowly through space, so that suppresses its speed towards the centre clock a bit, but because it will continue to have a lower speed through space than the middle clock, it's not going to stop or move backwards: it continues to move towards the middle clock throughout the experiment. As the middle clock decelerates though, it (middle clock) ticks faster, so that leads to a further reduction in the speed at which the outer clock moves towards it because the beeps are sent out at a higher rate than before, but again, so long as the middle clock continues to move in the same direction, the outer clock continues to move towards it. We have a distinct physical difference from the first case in that the outer clock is moving towards the middle one instead of away from it, although it's just possible that it might not look that way to the observer at the middle clock from the returning ping rate. The beeps are bounced back from the outer clock in such a way that they have a higher frequency than they were sent out with, but as the middle clock slows down its speed of movement through space (assuming that really happens), it sends beeps out faster (while always ticking more slowly than the outer clock and while the outer clock is always reducing the separation distance), but perhaps the returning pings could still come back to the middle clock at a lower frequency than they were sent out, thereby making it look as if the outer clock is moving away. The outer clock is always getting closer to it though in reality, so which effect wins out? I don't know: that's something that does need a set of specific numbers to be worked out for it, and maybe you've already done that and found complete masking of the difference between the two cases. Fortunately though, I don't need to rush to work out numbers because we can simply switch to a different method of measuring distance to settle the matter. With the middle clock slowing down, any length contraction on its parallax measurements of the distance to the outer clock will show the outer clock to be getting closer over time rather than further away, quite in addition to the fact that it is physically getting closer, so the observer sees it growing larger in his telescope, and the reduction of the distance between them is amplified for the observer as length contraction is lost - if there was a rod sticking out from the middle clock to the outer clock, for example, that rod would lengthen as the length contraction is removed, but the outer clock would not stay at the far end of the rod - the end of the rod and the outer clock would move away from each other with the outer clock continuing to get closer to the middle clock while the end of the rod extends further away. We thus still have a clear effect that is not being masked.

So no, this reduction of the middle clock's speed through expanding space does not mask absolute speeds. We still get different measurements from the experiment depending on the speed of the apparatus through space and there is no escape route for STR. The content of the previous two paragraphs needs to be checked rigorously though to see if it contains any errors, so that's the key thing to focus on.

From reply #27:-

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The bit about the rod stretching out to the clock that's at rest though still appears to evade the masking: the slowing of the middle clock will lead to lengthening of most of that rod, and the strongest lengthening will be at the end connecting to the middle clock. Any shortening of it will happen beyond the outer clock, so the rod will extend beyond the outer clock as the outer clock continues to reduce the distance to the middle clock. A rod going the opposite way to the other outer clock would lengthen along its whole length, so it might keep up with or overtake that clock even though that clock is moving away. (In the alternative scenario though where the middle clock is at rest, there would be no change in the length of the rods at all and both the outer clocks would move away from the middle clock.)

That is what the discussion should be focusing on: the question as to whether there is an error leading to these different predictions for the outcomes of the two scenarios.

From reply #28:-

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They do, because in the case when the middle clock is at rest, the two outer clocks are moving away from it and the length contraction on the middle clock and its view of the action does not undergo any contraction at any time. The outer clocks are both ticking more slowly and have to move further away from the middle clock continually, so they will be seen to get smaller.

Now, when the middle clock isn't the one that's at rest and if you can manage to contrive there to be total masking of the difference, then both outer clocks must be seen to move further away in all runnings of the experiment. Also, if you have a rod sticking out to the outer clocks from that middle clock when it's at rest, that rod will not extend to keep the tips at the outer clocks: they will move away from the rods. The same would have to happen in all runnings of the experiment for there to be total masking, but that doesn't look possible in the case where one of the outer clocks is the one at rest. It has to move towards the central clock, while the deceleration of the central clock leads to the entire rod between the middle clock and the one that is initially at rest losing some length contraction and thereby becoming longer with the tip moving further away from the middle clock than the clock that was initially at rest.

And all of that can be worked out and demonstrated just by using the numbers more and less (or words equivalent to them). You can make the deceleration any value you like and you can choose any value you like for the middle clock's speed: the description will fit all such cases. That is the power of using these special numbers in mathematics, and it's the way mathematicians think before the resort to the calculator, leading to them very rarely needing to pick one up when exploring things like this.
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We're using frequency of arrival of beeps. If the middle clock is decelerating, that will affect the times taken for the beeps to cross the divides between clocks, but in the version where that's happening, all we depend on is that the outer clock keeps positioning itself to receive the beeps at the right times, so when the middle clock decelerates, the outer clock decelerates accordingly while continuing to get closer to it, which it must do because it is still ticking faster than the middle clock. For example, if the middle clock's moving at 0.866c and ticking half as often as the outer clock, a deceleration of the middle clock to 0.8c would still leave it ticking 0.6 times as often as the outer clock if it wasn't closing the gap, so the outer clock still has to race into the signal while the rod extends to a greater length in the opposite direction. That's a difference that isn't being masked, and unless I've made some big mistake in this analysis, it shows that no one's ever worked through this adequately before.

From post #30

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In my paper I wasn't taking into account the decelerations that you say happen, so it was using {I} frames that behave differently from yours. That was the thing I didn't know about, and it's the thing that messes up the original version of the experiment because it makes it impossible to know if the separations are constant. Hence the shift to a version where the outer clocks move and just maintain a constant perceived rate of beep arrivals from the middle clock.That was your big contribution to this - you drove that change days ago, but it's taken you a long time to notice because you're still spending most of your time keeping arguments about an obsolete version going instead of switching attention to the key issue.

If you actually test the right version of the experiment in which the outer clocks actively move to maintain a constant perceived arrival rate of one beep per second from the middle clock), then your pronouncements might finally be directed at the actual target.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 16/06/2021 04:07:49
Quote from: D.C
The rod loses contraction while the trailing outer clock moves nearer to the middle clock in the case where that outer clock is initially at rest (in {C})
Fair enough to bolt the middle clock to the rod, but the outer clocks are required to move either towards or away from the middle clock (or stay still) in order to receive a perceived beep arrival rate from the middle clock of one beep per second.
This is actually empirical. So you’re saying that, in spacetime free of gravity and dark energy, if one bolts a clock (the one where the measurement takes place) to a rigid (admittedly super-long) rod (effectively just there as a tape measure) and a second clock is moving at just the right speed along that rod either outward or inward (you indicated inward in the enclosed quote), that a signal sent at one per second from that clock moving relative to the rod is going to be received at exactly 1 per second. That’s a pretty remarkable claim and such an observation would indeed falsify both relativity and LET. Accepted physics says any signal from the inbound clock will be blue shifted, as will any signal received from the bolted clock as measured at the inbound clock. This is regardless of what part of the rod, if any, is stationary relative to {C}.
If you assert this, then you can leave the clocks bolted to the rod and any measured red or blue shift will falsify STR. No need to calculate the exact acceleration required to prevent this. But you need numbers, because only then can the flaws be specifically identified. We can post day and night denying each other’s assertions, but numbers talk. Which of my numbers is wrong, and why? You avoid discussing numbers because you know what they’ll show.

I will point out that using {C}, the one clock will need to move in to maintain constant separation distance. In my example, it started out at a distance of only 2.3 and is working its way up to over twice that. To maintain constant separation distance from the bolted clock, it would need to be moving in but accelerating (proper) outward. Such a pair of clocks would each appear blue shifted as observed by the other.

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We start with one of the outer clocks at rest {C}
Just like my example, except mine has numbers. That stationary one is a spatial location 0 in both CS. It kind of makes an intuitive origin. My example had the one stationary and the clock bolted to the other end of the rod moving at near light speed. I didn’t put anything in the middle. I could if you think it helps. Your scenario seems to assign the role of my moving clock to this middle one.
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while the middle clock has space moving through it in the direction away from that outer clock, so the outer clock (we can ignore the other outer clock for now) is ticking faster than the middle clock and has to move towards it until it receives the required perceived beep arrival rate from the middle clock of one beep per second, and then it tries to maintain that by continuing to move towards the middle clock.
OK, I understood all that, but ‘the outer clock’ seems to always refer to the stationary one despite there being two outer clocks. Maybe it will come into play later. I recommend names for them (L,M,R) for left, middle, right where L is stationary, at least at first. Yes, L ticks the fastest in {C}You’re planning to apply proper acceleration to it, which you claim will cause the observer at M to measure signals with no redshift.
Just checking that I got it right. You know I disagree with the acceleration necessity.
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If the middle clock somehow isn't decelerating in {C}
Then something is applying proper acceleration to it. Kind of invalidates the experiment if you do that.
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then the rod won't change length
The inertial rod has to change length due to the changing expansion rate which is 1/T. The expansion rate is a function of time, and the scalefactor is completely linear in our special gravity-free case.
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If you have the middle clock decelerating in {C} though (which is what you say must happen), then the rod will lengthen in addition to the outer clock moving along it, so we have the tip of the rod moving away from the middle clock while the outer clock moves nearer to the middle clock.
Erm, in {C}, the tip will indeed increase its separation distance from M, but the outer clocks will not necessarily get nearer just because they’re moving inward along the rod. They’d have to outpace the rate at which the rod is lengthening, else they’d still be getting further away, just at a lesser rate. You’ve given no numbers as to what rate these outer clocks would have to move along the rod, or how you conclude a lack of blueshift from doing this. Clue: There a ton of calculus involved. I write programs to do the calculations for me.
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Either way that's a measurable effect, and a very different one from the alternative situation in which the middle clock is at rest in {C}.
Of course under LET, you get no redshift only if you leave all clocks bolted to the rod, and therefore the experiment measures the same thing regardless of initial motion of the rod in {C}. You on your own with these assertions. I cannot show your mistake with no numbers to critique.
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Everything's at a halt until you understand the actual experiment and stop trying to turn it back into the obsolete one in the paper.
OK, you applying thrust to your clocks now.
I kind of ignored your earlier posts because they were almost all metaphysics, and completely lacking in frame references. You seem to really believe your assertions despite not having actually plugged in any real numbers. There’s no point in responding to that, so I haven’t much. I do remember responding to certain parts that were empirical.
Bit of a problem applying that to my scenario since my rod is so long, the universe quintuples in age before the first signal travels from one end to the other. It’s almost impossible to discuss your scenario since the precision required is insane, hiding properties that are made obvious at larger scales.
Why not discuss my case? It has actual numbers. Two clocks bolted to a rod with one end stationary. You claim the stationary end will measure red-shifted signals from the far end. My calculations show no such redshift, but admittedly I haven’t added seconds to my otherwise generic units. I can send a second signal exactly one time unit later as measured by the local (slow ticking) clock, which should be received at time 11 where the first was received at 10. Note that the one signal takes 9 time units to get to the stationary measurement location from a distance of only 2.3, a clear illustration of 1-way speed of light being slow when going against the space fabric. Light going the other way (with the wind so to speak) certainly didn’t take that long.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 16/06/2021 23:22:13
This is actually empirical. So you’re saying that, in spacetime free of gravity and dark energy, if one bolts a clock (the one where the measurement takes place) to a rigid (admittedly super-long) rod (effectively just there as a tape measure) and a second clock is moving at just the right speed along that rod either outward or inward (you indicated inward in the enclosed quote), that a signal sent at one per second from that clock moving relative to the rod is going to be received at exactly 1 per second.

You're nearly there now, but the beeps are produced by the middle clock - the one the rods are attached to. The outer clocks respond to that by moving in order to get the required perceived beep arrival rate of one per second.

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That’s a pretty remarkable claim and such an observation would indeed falsify both relativity and LET.

It would not falsify LET because LET has always recognised that there are absolute speeds through space and automatically predicts that there will be a difference with this experiment depending on which of the clocks has the lower average speed through the space fabric local to it.

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Accepted physics says any signal from the inbound clock will be blue shifted, as will any signal received from the bolted clock as measured at the inbound clock. This is regardless of what part of the rod, if any, is stationary relative to {C}.

The signal from the middle clock is either constant when it's at rest in {C}, so we'll call that case 1, or it's very gradually increasing its ticking rate as it slows its speed of travel in the direction of rest in {C}, which is case 2. In case 2 where it's not at rest in {C} and one of the outer clocks is closer to being at rest in {C}, that outer clock will be ticking faster than the middle clock and has to move towards the middle clock in order to perceive the beeps from the middle clock at the required frequency. In case 1 though where the middle clock is at rest in {C}, neither of the outer clocks are at rest in C, so they are ticking slower and have to move away from the middle clock in order to perceive the beeps at the required frequency.

In case 1 you can give the outer clocks any initial speed you like and then let them adjust until they get the right perceived beep rate arriving. In a case where all three clocks are at rest in {C} initially, the two outer clocks will have to accelerate in the direction of the middle clock, so that at first sight looks as if they're not doing what I described previously, but they are merely decelerating to a speed which will still leave them moving away from the middle clock. You can put the outer clocks anywhere along the line and with any initial speeds along that line, and they will always be moving away from the middle clock after adjusting their speed until they receive one beep per second. And in this case, the rod is of constant length, so the clocks will move outwards towards the tips and then beyond them, never to return.

In case 2, it's radically different. We can again put the outer clocks anywhere along the line with random speeds along the line and let them adjust. If we have one clock at rest in {C} which is at the end of one of the rods sticking out from the middle clock with the end of the rod almost stationary relative to the middle clock - it will be moving away from it slightly due to gradual loss of contraction as the middle clock decelerates, then the clock which is at the end of the rod at that moment will need to move towards the middle clock, and so will any other clock placed between that clock and the middle clock if they're all trying to get the same perceived beep arrival rate. These clocks will all move in the opposite direction to the tip of the rod. Nothing of that kind can happen in case 1.

I'll let you explore that before describing other cases.

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You avoid discussing numbers because you know what they’ll show.

I don't avoid them: I just use wide-range versions of numbers, and if you pick any specific values within the stated ranges you will find that they fit with what I said applies to the entire range.

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I will point out that using {C}, the one clock will need to move in to maintain constant separation distance. In my example, it started out at a distance of only 2.3 and is working its way up to over twice that. To maintain constant separation distance from the bolted clock, it would need to be moving in but accelerating (proper) outward. Such a pair of clocks would each appear blue shifted as observed by the other.

This is why the older version of the experiment became obsolete: keeping the separations constant became impossible to manage as soon as you showed that the middle clock could be slowing: we can't know if it's at rest in {C} or moving, so we can't guarantee keeping the separation distances constant, and that scrambles the results. The cure was to switch to a constant perceived beep arrival rate. If there's no expansion of space, that would always lead to clocks ending up maintaining constant separations to the clock putting out the signal. With expansion though, constant distances cannot be maintained due to the clocks moving at different speeds through the space fabric and ticking more slowly if they're moving faster (while the distances are constant). That drives movement, and an outer clock ticking faster than the middle clock has to move towards the middle clock, whereas an outer clock ticking slower than the middle clock has to move away from it. We then only have to look at what they're doing relative to their local part of the rod which is attached to the middle clock. If the middle clock is at rest in {C}, the length of the rod is constant. If the middle clock is moving in {C}, it will be decelerating very gradually and at least part of one half of the rod will gradually lengthen. There are complications where both tips of the rod can be getting shorter while the parts of the rod nearer to the middle clock are lengthening, but I've pointed you above to a range of situations where that doesn't affect the result because any contraction being increased for the tip is further out than the outer clock, so the clock is passing part of the rod that is extending in length.

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Yes, L ticks the fastest in {C}You’re planning to apply proper acceleration to it, which you claim will cause the observer at M to measure signals with no redshift.
Just checking that I got it right. You know I disagree with the acceleration necessity.

Acceleration is needed to adjust the speed, but most of that will be applied at the start to get the speed right, after which it'll stay in sync with very little subsequent acceleration. We do the same thing in both case 1 and case 2, but we have L settling down to move away from M in case 1 while in case 2 we have L settling down to move towards M. If we name the tips (outer ends) of the rod TL and TR, then in case 1 we have L moving away from M and passing a static TL (which is at a constant distance from M), while in case 2 we have L moving towards M and passing TL while TL actively moves further away from M due to the reducing contraction of the rod in between L and M.

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If the middle clock somehow isn't decelerating in {C}
Then something is applying proper acceleration to it. Kind of invalidates the experiment if you do that.

I'm just covering a hypothetical case in which objects don't slow towards rest in {C}. You are welcome to ignore that situation if you think it impossible, but I have to cover it to shut down that escape route.

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then the rod won't change length
The inertial rod has to change length due to the changing expansion rate which is 1/T. The expansion rate is a function of time, and the scalefactor is completely linear in our special gravity-free case.[/quote]

Each part of the rod in case 1 is in a constant state throughout with no change in the contraction applying to it, so there is no change in its length at all. In case 2 it's different: the middle of the rod is slowing down in {C}, so the innermost parts of the rod are losing contraction. That is not always true of the tips though: they can be contracting if they're being pushed far enough away to be increasing their speed through the local space fabric.

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If you have the middle clock decelerating in {C} though (which is what you say must happen), then the rod will lengthen in addition to the outer clock moving along it, so we have the tip of the rod moving away from the middle clock while the outer clock moves nearer to the middle clock.
Erm, in {C}, the tip will indeed increase its separation distance from M, but the outer clocks will not necessarily get nearer just because they’re moving inward along the rod.

So long as L (forget about what R is doing for now) is moving at a lower speed through space than the middle clock, it will continue to get nearer to it. It will never reach a time where it moves faster through space than the middle clock and will only reach the same speed through space as the middle clock in an infinite length of time when they meet.

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They’d have to outpace the rate at which the rod is lengthening, else they’d still be getting further away, just at a lesser rate.

It has no trouble doing that: it has to continue to approach the middle clock so long as it is moving through space at a lower speed and is ticking faster than the middle clock, and that situation never changes. It will have to slow down, but it will always keep closing in on the middle clock.

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You’ve given no numbers as to what rate these outer clocks would have to move along the rod, or how you conclude a lack of blueshift from doing this. Clue: There a ton of calculus involved. I write programs to do the calculations for me.

I provided an entire range for you to choose from and demonstrated that any clock L in that range must continue to move towards the middle clock. You don't need to do the ton of calculus because you can consider any location between L (initially at rest in {C}) and M and put a clock there moving at any initial speed you like along the line: every single one of them will have to adjust speed until it is moving towards the middle clock, and the closer it is to the middle clock, the higher its speed through the space fabric it will be moving at, but it will be closing in more slowly on the middle clock. You only need to consider a few locations within that range to test that - there are no exceptions.

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Of course under LET, you get no redshift only if you leave all clocks bolted to the rod, and therefore the experiment measures the same thing regardless of initial motion of the rod in {C}. You on your own with these assertions. I cannot show your mistake with no numbers to critique.

I've given you a range with tight boundaries. The outer boundary is where L is initially at rest in C and at a constant distance from M {in C}. You can put a whole series of clocks L1, L2, L3, etc in between L and M wherever you want them and give them any initial speed you like: they will immediately adjust their speed to achieve the required perceived beep arrival rate of one beep per second and that will set them moving towards M.

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It’s almost impossible to discuss your scenario since the precision required is insane, hiding properties that are made obvious at larger scales.

Several posts ago I suggested having L at rest and M moving at 0.866c through the space fabric while both of these clocks are initially at a fixed separation. That has M ticking half as often as L, so L has to accelerate towards M. If L was to accelerate to 0.866c, it would then receive too high a perceived beep arrival rate because both clocks would be ticking at the same rate as each other, so L has to settle for a speed somewhere in between 0 and 0.866c. It will thus tick more quickly than M while it moves towards it, and it will receive what it perceives as one beep per second. Two factors will change over time. As the distance reduces, L is moving faster through the space fabric due to the expansion of space, so its ticking slows and it has to decelerate to maintain the required perceived beep arrival rate, but it's still moving more slowly through space than M, so it's still ticking faster than M and continues to move closer. M is also slowing down in {C} very gradually, and this slowing causes it to move towards the right, so that leads to L having to move faster to the right to match that, so it reaches higher speeds through the space fabric a little sooner than it would otherwise, but it continues to move more slowly through the space fabric at all times while ticking faster than M at all times and while closing in on M at all times. You can tell that just by imagining a series of clocks at fixed distances from M which L is passing, and you can see that every single one of them would have to move closer to M if it was to receive the required perceived beep rate, so clearly clock L must always pass them and continue to reduce the distance to M. So, if you want to put specific numbers to this, you can take that string of imaginary clocks at fixed distances from M, all using {C} and your God view of the action, and you can work out how fast each of them would need to move towards M in order to receive the required perceived beep rate from M, each time taking into account their increasingly higher speed of movement through the space fabric, though they're all moving through it more slowly than M is. That shows you how L will behave over time because it will pass each of those imaginary clocks at the speeds the they would need to be moving at if they were to comply with the perceived beep arrival rate rule. You could also work out values again for a series of moments in time while taking into account the gradual slowing of M through the space fabric and its movement to the right, but the difference will be that all those imaginary clocks at fixed distances from M will still be moving more slowly through space than M and so L will always have to pass them and move nearer to M, all while the contraction on the rod from L to M reduces and pushes every part of that rod between L and M further away from M. Not that after L has passed an imaginary clock and M has slowed down, that imaginary clock may at some point end up at rest in {C}, and later on it can reach a point where the rod local to it is contracting rather than lengthening, but that's digging into the complications. If we just consider where L is, while M gradually slows down, L always stays between M and the place where an imaginary clock would be at rest in {C}.

Or does it? What if there's a mistake there? What happens if L moves towards M more slowly than the at-rest-in-{C} location for an imaginary clock moves towards M? Well, just supposing that's the case, and I can't rule it out at the moment, we can simply reduce the range we're looking at and start L half way between that at-rest-in-{C} location and M, whereupon we can guarantee that it has to close in on M for a considerable length of time, and during that time it would be moving past the markings on the rod to the side of it while they are pushed further away from M.

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Why not discuss my case? It has actual numbers.

Because my cases show an effect, while yours follows the abandoned approach of my paper: you showed up a problem with that caused by our inability to know if our distance is constant, and your numbers for that situation appeared to show masking of the differences. That was your important contribution to this. For that reason, I think it's better to look at a case where we have clear unmasked differences.
Title: Re: Does this experiment disprove relativity?
Post by: Halc on 17/06/2021 02:58:02
This is actually empirical. So you’re saying that, in spacetime free of gravity and dark energy, if one bolts a clock (the one where the measurement takes place) to a rigid (admittedly super-long) rod (effectively just there as a tape measure) and a second clock is moving at just the right speed along that rod either outward or inward (you indicated inward in the enclosed quote), that a signal sent at one per second from that clock moving relative to the rod is going to be received at exactly 1 per second.
You're nearly there now, but the beeps are produced by the middle clock - the one the rods are attached to.
I didn’t say otherwise above. So you really are claiming this.
Go ahead and publish this, all sans mathematics as you have done. Please don’t include any reference to me anywhere.
I call nonsense on it. You’re just guessing, and very much guessing wrong. Your maths are not wrong because you haven’t done any. This isn’t the way to go about publishing this sort of thing.
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I'll let you explore that before describing other cases.
There’s nothing to explore. No mathematics, and the rest is just a repeat of prior assertions.
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I just use wide-range versions of numbers, and if you pick any specific values within the stated ranges you will find that they fit with what I said applies to the entire range.
I seem to be the only one to have actually chosen some numbers, and they don’t show this at all. You haven’t expressed any interest in those numbers.
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Each part of the rod in case 1 is in a constant state throughout with no change in the contraction applying to it
There’s another fantastic assertion. It implies a fixed expansion rate (and a very different coordinate system than {C}), which, extrapolated backwards puts the size of the visible universe at about 40% of what it is now back 14 billion years ago, a far cry from the size of a grapefruit.
You need to read up on some introductory cosmology texts. You’re not taking anything I say seriously, so get it from texts instead of me if you think I’m just another one of the nutters on this site asserting his opinions instead of looking things up on reputable sites in situations in which I am unclear.
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You don't need to do the ton of calculus
To get numbers, you very much do. None of my numbers are from typing a couple of operations into a calculator. Hyperbolic coordinates are nasty to work with directly.
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Several posts ago I suggested having L at rest and M moving at 0.866c through the space fabric
Mine has the one end moving at .98c. but .866c is enough. Post 12 moves the short apparatus at .866c, but L is certainly not at rest in that case. I think you’re talking about post 28. Unfortunately you computed nothing in that post except that if M slowed from .866c to .8c, its tick rate would up by a fifth. No other numbers. No computation of how long a signal would take to go from one end to the other, and also how long it takes to go the other way. Without that computation, you have no business asserting what will be measured by anybody. It becomes a mere guess, which is just not how physics is done.

Short post today. One new assertion. No new numbers.
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 17/06/2021 07:01:43
I gave you all the numbers necessary to set out the case, but I did miss something crucial which I've come back online to post now, because I've now found that the way looks open to complete masking of the difference between case 1 and case 2.

The key thing was to look at the way M behaves. M decelerates in {C} until it's at rest in {C}, but that turns out to be an acceleration in {I} using the frame in which L and M are both initially at rest. We also have a delay in propagation of the signals travelling to L from M, so L does not respond promptly to M's acceleration in {I}. Furthermore, if we run back time to before that starting point, we find that M must previously have been moving to the left in {I}, and it slows in {I} until it is at rest in {I} at the official starting point of the action. Because it was moving to the left up until then, the beeps are closer together than I previously thought they would be on their way from M to L, which means that L could need to move left rather than right in order to receive the required perceived beep rate. Also, while M is moving left and slowing to a halt in {I} by the starting point of the experiment, it's moving slower in {C} at all times and is losing length contraction on the rod, so the tip of the rod will be moving to the left in {I} up until the start and will continue to do so for some time after M has stopped in {I}. All of this could potentially lead to L and TL (the local tip of the rod) moving at similar speeds to the left. For complete masking, L would need to be moving to the left a bit faster than TL in order to match what happens in case 1 where M is at rest in {C}. Calculating precise numbers for that could take a lot of work to handle all the different amounts of loss of length contraction on different parts of the rod at different times with all the different delays acting in different places, but it looks so neat that I wouldn't now bet against there being complete masking. I've certainly broken my own argument, or rather, one big part of it.

What remains the case though is that without complete masking, the experiment would be able to disprove STR directly in expanding space. However, if we do have complete masking, which now looks more than possible, then it would lead to a null result in expanding space and prove that either there's no expansion (which isn't going to happen because that would cause to many problems explaining the CMB and big bang), or that objects really do slow towards being at rest in {C}, which would again disprove STR, this time by proving that there is such a thing as absolute rest in the space fabric. And we also still have the original thought experiment with clocks, watches and miniwatches being created soon after the big bang which again shows STR failing due to there being different results from cases which STR considers identical (with case A having the watches accelerate away from the clocks and be seen to have ticked slower when they pass other clocks, while the miniwatches which accelerate away from a set of watches which are all moving in the same direction and where the miniwatches end up at rest relative to the clocks, we see that the miniwatches have ticked faster when they pass other watches). It's surprising that it looks as if that original experiment likely can't be translated into experiments of the kind I've been exploring where we could do local experiments without outside help, but we could in principle still duplicate that original experiment by having lots of aliens help out by sending out watches at very high speeds and those watches immediately send out miniwatches at very high speeds the opposite way such that they stay right next to the aliens' clocks, after which whenever a watch passes another alien's clock and miniwatch, it will have registered less time passing than the clock and miniwatch, thereby revealing that it's the watches that are moving at very high speed while the the aliens are close to being at rest. So, we still have an experiment that could be carried out for real in a universe to produce such results, but it needs the help of numerous tribes of aliens in other galaxies.

Thanks for your help, Halc: that bit about things slowing towards rest in {C} was crucial to getting to this point and revealing more about the extraordinary ability of the phenomenon of relativity to mask what's going on, except here it is only able to do it by revealing the absolute frame, and that's the most brilliant thing about it. The masking ultimately breaks itself. What a fantastic story it turned out to be.
Title: Re: Does this experiment disprove relativity?
Post by: Origin on 17/06/2021 14:43:18
Thanks for your help, Halc: that bit about things slowing towards rest in {C} was crucial to getting to this point and revealing more about the extraordinary ability of the phenomenon of relativity to mask what's going on, except here it is only able to do it by revealing the absolute frame, and that's the most brilliant thing about it. The masking ultimately breaks itself. What a fantastic story it turned out to be.

So to answer the question, "Does this experiment disprove relativity?"  Obviously not.

It is always so interesting to me that someone who is incapable of doing freshman physics problems, thinks they are smarter than all the physicist in the world.  Just bizarre.  It is like someone reads a few wiki pages on medicine and thinks they are now ready to perform brain surgery!
Title: Re: Does this experiment disprove relativity?
Post by: David Cooper on 18/06/2021 02:30:16
So to answer the question, "Does this experiment disprove relativity?"  Obviously not.

I didn't write the question - this was split out from another thread - but the experiment does actually contribute to a disproof of relativity.

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It is always so interesting to me that someone who is incapable of doing freshman physics problems, thinks they are smarter than all the physicist in the world.  Just bizarre.  It is like someone reads a few wiki pages on medicine and thinks they are now ready to perform brain surgery!

If you were more capable than that, you'd recognise that the above helps disprove STR and that it's your analysis that's bizarre. I'm actually checking the subject properly to test established beliefs to destruction. When my ideas don't work, I recognise that and say so (as above where I thought there was incomplete masking but it now looks as if there may be complete masking after all), but when they get something wrong like STR they just cling to the corpse and assert endlessly that it's still alive. Halc showed me something important which revealed that two of the three thought experiments don't work in cases where things slow towards absolute rest in {C}, but that very fact of them slowing to absolute rest in {C} is incompatible with STR in itself, so STR requires it not to be the case, while if it isn't the case that things slow to absolute rest in {C}, then both the experiments come straight back into play by disproving STR. The thought experiment with clocks and watches sent out at the big bang stands in all cases and again disproves STR. The people who still think STR is viable are the ones who you should be attacking here.

And who of the experts like you who are so capable was able to come in and point out the faults that I found at the end of this myself? I deliberately write the way I do in order to attract gleeful corrections from people who can help identify errors sooner, but where are those people? You couldn't find the errors, so you just come in at the end to snipe after I've resolved it. That's easy for you to do, and you're keen to throw insults now that you think it's safe to do so, but what's your contribution to this? I've found half a dozen independent ways to disprove STR while you've found nothing. Most of them are simple, so do you want to see them? Here we go:-

Disproof 1

Imagine two objects moving at 0.5c relative to each other along a straight line. We introduce a pulse of light which moves along the same line at c relative to the first object. The speed of that light is 0.5c or 1.5c relative to the second object (depending on which direction along the line that object is moving in). STR denies that measurement and insists that the correct relative speed for the light and second object is c, but if the relative speed of the light to both objects is c, the two objects cannot be moving at 0.5c relative to each other: their relative speed to each other would have to be zero.

What’s going on here? Well, Einstein bans you from accepting some measurements between light and objects that travel at lower speed than c. He requires you to change frame to make the second object stationary, and only then will he accept the relative speed for the light and that object. In that new frame, the relative speed between the
light and the first object is now 1.5c or 0.5c, but again he bans you from accepting that measurement. So, he mixes frames to get the two measurements which he wants to make so that they conform to his bonkers theory, and he rejects all measurements that disagree with his ideology. In the course of changing frame, he changes the speed of the light relative to both objects. In doing so and mixing frames, he is making an illegal mathematical move.

Disproof 2

Picture an observer watching two ships in the distance which are passing each other, one moving towards him and the other moving away from him. The two ships each put out a flash of light at the moment when when they are side by side. These two flashes of light travel alongside each other all the way to the observer who sees them both arrive simultaneously. How did the two flashes of light know to travel at the same speed as each other? Did they decide to travel at c relative to one ship rather than the other ship? Did they decide to travel at c relative to the observer? They aren't going to know how the observer's moving until they reach him, so they can't do that. Also, we can have some of the light pass the first observer and be seen by a second observer further away who is moving relative to the first observer along the same line as all the rest of the action, so is the light supposed to move at c relative to that observer too?

Einstein would have you believe that the speed of the light is c relative to both observers, but that would mean the two observers couldn't be moving relative to each other. There could also be observers on the two ships who see the flashes pass them, and again Einstein wants the speed of that light to be c relative to them. He is trying to have an infinite number of contradictory things all happen at the same time. In reality, the speed of the light is c relative to the space fabric and needn't be c relative to any of the ships or observers at all. As soon as you deny the space fabric and its absolute frame, you lose the ability to govern the speed of the light from one flash to make it move at the same speed as the light from the other flash: each flash would have to travel at c relative to the ship that it was emitted from, so the light from one flash would reach the observer before the light from the other flash. Einstein's insistence that the speed of light is always c relative to any observer is nothing more than a contrived mathematical abstraction, and it breaks fundamental rules by tolerating contradictions - if he has the light move at c relative
to all ships and observers, he has it moving at four speeds relative to itself. The big mystery here is how people can buy into Einstein's magical thinking and imagine that they're doing science.

Disproof 3

There were experiments which disproved Einstein's STR a century ago. The Michelson-Gale-Pearson is one of those, though it wasn't recognised as such at the time. It is only today with greater minds than Einstein looking at the evidence that we can see what this experiment actually revealed. Two lots of light were sent round a rotating ring, and one lot of light returned to the emitter before the other, just as it does in the Sagnac experiment. The light that travelled in a clockwise direction passed all the material of the ring at a higher speed on average relative to that material while local to it than the light travelling the opposite way. This is observed to be the case by observers in all reference frames so it is beyond dispute. The length contraction on the ring is the same in both directions, so it clearly destroys Einstein's assertion that the speed of light is always c relative to any observer - we can put observers all round the ring, each one moving with their local part of the ring, and we know that the light must be passing some of them at speeds other than c relative to them.

Disproof 4

The twins paradox proves that there's an absolute frame of reference by showing that clocks can tick at definitively different rates from each other under the governance of their absolute speeds of motion through the space fabric. If we give the stay-at-home twin clock A, then the other twin can travel with clock B away and back at 0.866c. On return, when they compare their timings for the separation, clock A ticked twice as many times as clock B, so clock B was clearly ticking slow due to its faster speed of motion through the space fabric. Fans of STR will assert that you have to switch to GTR to account for the action here because it involves acceleration, and they imagine that something magical happens at those points where clock B is accelerating, but we can eliminate the role for that magic by introducing two additional clocks. Clock C travels alongside clock B on the outward leg, and clock D travels alongside clock D on the return leg. Neither of these new clocks accelerates at any point. Clock C makes a timing from when it passes clock A until it passes clock D. Clock D makes a timing from when it passes clock C to when it passes clock A. Timing B = timings C+D, confirming that the only role for the accelerations of clock B was to change its absolute speed of motion through space. We get the result timing A = 2(C+D). In all cases with the twins paradox, you get A > C+D. If there was no space fabric and no absolute frame, clocks A, C and D would all have to be ticking at the same rate as each other, but that would give us the result A = C+D, which is a result that the universe never provides.

Disproof 5

Imagine two observers, one at the centre of a circle and the other going round and round the edge of the circle. The distance between the two remains constant, so the Doppler effect doesn't need to be taken into account when they observe each other's clocks. Let’s have the orbiting observer move at 0.866c, so he will have his functionality slowed to half its normal rate, so he will be seen by the observer at the centre as living in slow motion. When the orbiting observer looks at the other observer though, he sees him speeded up, so this is not symmetrical. Believers in Einstein’s STR don’t like that result, so they go in for obfuscation at this point and talk about accelerations and a need to switch from STR to GTR, but no: you can do the entire analysis with STR, and when you do that you find STR to be plain wrong.

How? Just send lots of clocks at 0.866c along tangents to the circle such that during any short stretch of the orbiting observer’s trip he’s travelling alongside one of those clocks that’s following a tangent to the circle and matching him for pace. We compare the ticking rate of his clock with the clock flying alongside him for a moment and we see that their ticking rates are near identical. These clocks following the tangents never accelerate. We can replace the orbiting observer with a chain of clock timings where we convert the circle into a polygon with straight sides. Each side has a clock run along it without accelerating at any point, and it touches the next clock for a moment as they pass and the new clock takes up the “baton”. This imaginary baton is passed from clock to clock until it has done a complete circuit, and when we look at all the timings, lo and behold, we discover that these clocks were on average ticking half as often as a clock at the centre. Accelerations clearly have no role in this whatsoever: the slowing is caused solely by their absolute speeds of motion through the space fabric.

Disproof 6

This one's a simulation which shows STR generating event-meshing failures in mode 1 and contradictions in mode 2: magicschoolbook.com/science/double-twins-paradox.html (http://magicschoolbook.com/science/double-twins-paradox.html). All possible versions of STR break in one or other of those ways. And for the record, here is GTR breaking by generating event-meshing failures too: magicschoolbook.com/science/Event-Meshing-Failures.html (http://magicschoolbook.com/science/Event-Meshing-Failures.html).

And the collected thought experiments discussed in this thread add up to another two disproofs, though one of those in combination with Halc's revelation that things slow to absolute rest in expanding space.

So while you try to describe me as "someone who is incapable of doing freshman physics problems", the people you should be attacking in that way are the ones with top qualifications who insist on backing those dead theories, because they can't even do the high school maths correctly to be able to identify a contradiction.