[David Cooper]

What are you talking about?
There is no circle in the diagram. Please, stay true what is presented on the diagram,
Jano

The red dot (representing a clock) travels in circles around the white clock. (The blue and green dots follow straight lines at all times.) Some people who are red-green colourblind have difficulty seeing red against a black background, so I may need to change it to a different colour if that's the issue here.

[David Cooper]

The twin paradox is not actually a paradox

It isn't a paradox as it has a resolution in LET, but it remains a paradox in STR. Just as you can remove the acceleration issue from the circling case, you can do this with the twins paradox, so let's do that now. 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, but people like to attribute that to the accelerations. We can eliminate the role for acceleration though just 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. Without a space fabric and 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. STR demands that A ticks faster than C while C ticks faster than A. It also demands that A ticks faster than D while D ticks faster than A, and that C ticks faster than D while D ticks faster than C. Those are all paradoxical. But what the twins paradox shows us is that A always ticks faster than C or D (if not than both of them), and that's an asymmetrical requirement. The only symmetry involved in it is with our inability to pin down whether A is ticking faster than C or D if it isn't ticking faster than both of them, but A > C+D demands that A is ticking faster than the average of C and D. There has to be a relationship between A and C or A and D in which A is ticking at a faster rate than the other clock while that other clock cannot also be ticking faster than A. The symmetry breaks.

[Jaaanosik (OP)]

From this book:



Why is the author saying that time on the Earth is flowing more slowly?
Because it is based on the SR, the time dilation is reciprocal.
Please, have a look here:



The mysterious jump cannot happen.
The event P or the event C in the other diagram are when the travelling twin stops at the return point.
This is the spot where both twins are in the same reference frame. There is nothing weird happening.
The question is what is the time on the clocks at the turning point when they are in the same frame and the simultaneity line is the straight horizontal line?
Jano

[Kryptid]

It isn't a paradox as it has a resolution in LET, but it remains a paradox in STR.

I thought Lorentz ether theory and special relativity made identical physical predictions, the only difference being some of the underlying mechanics where LET invokes an ether and SR does not.

[Jaaanosik (OP)]

The twin paradox is not actually a paradox

It isn't a paradox as it has a resolution in LET, but it remains a paradox in STR. Just as you can remove the acceleration issue from the circling case, you can do this with the twins paradox, so let's do that now. 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, but people like to attribute that to the accelerations. We can eliminate the role for acceleration though just 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. Without a space fabric and 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. STR demands that A ticks faster than C while C ticks faster than A. It also demands that A ticks faster than D while D ticks faster than A, and that C ticks faster than D while D ticks faster than C. Those are all paradoxical. But what the twins paradox shows us is that A always ticks faster than C or D (if not than both of them), and that's an asymmetrical requirement. The only symmetry involved in it is with our inability to pin down whether A is ticking faster than C or D if it isn't ticking faster than both of them, but A > C+D demands that A is ticking faster than the average of C and D. There has to be a relationship between A and C or A and D in which A is ticking at a faster rate than the other clock while that other clock cannot also be ticking faster than A. The symmetry breaks.

The Triplet paradox cannot be resolved with the logic posted above, just check the times here:



The times will not add up. Why is that?
The acceleration is not an issue, agreed:



Because it can be replaced with the average relative motion as per the figure above,
Jano

[Jaaanosik (OP)]

Kryptid,
Question, how is it possible that when the travelling twin is in 'the same reference' frame, has almost 0 relative speed there are the biggest proper time deltas between the reference frames?
Please, see the blue lines.
Do you agree that this does not make sense?
Jano

[David Cooper]

It isn't a paradox as it has a resolution in LET, but it remains a paradox in STR.

I thought Lorentz ether theory and special relativity made identical physical predictions, the only difference being some of the underlying mechanics where LET invokes an ether and SR does not.

No. LET makes conditional predictions (meaning that they're all predicated by "if this is the absolute frame") while STR makes absolute ones (in which the absolute frame is denied and all the predictions are considered absolutely correct even when they contradict each other). The latter retains a paradox in its toleration of contradiction.

For example, suppose clock A (the stay-at-home twin's clock) sounds an alarm half way between twin B's departure and return. When twin B is at the turning point half way through, we can have him do a little jiggle where he accelerates to turn round and accelerates to 0.866c towards home, then accelerates to turn back and go outwards again for a moment at 0.866c away from home, then accelerates to turn back again for the long return towards home at 0.866c. Look at the predictions that he makes between those accelerations when moving at constant speed. Just before the first turn round, his calculations using STR where he counts himself as stationary tell him that the alarm has not sounded yet at clock A. After the first of the three turn-arounds, his new calculation using the new frame that he's stationary in tells him that the alarm has sounded at clock A. After the second turn-around, his new calculation tells him that the alarm has not sounded yet at clock A, and after the third turn-around, his new calculation tells him that the alarm has sounded at clock A. These predictions in STR are all supposed to be equally valid, but mathematics tells us that they cannot all be true because the middle two contradict each other, and if they are not equally true, they are not equally valid. In LET, they do not contradict because the predictions are conditional and the conditions are not always met.

[alancalverd]

The red dot (representing a clock) travels in circles around the white clock.

And there's your problem. Circular motion requires continuous acceleration towards the center of the circle, so there is no symmetry between an orbiting twin and a stationary one.

[Halc]

I thought Lorentz ether theory and special relativity made identical physical predictions, the only difference being some of the underlying mechanics where LET invokes an ether and SR does not.

The two theories do make identical predictions. Dave has a long history of creating straw man arguments against SR, such as the statement below:

LET makes conditional predictions (meaning that they're all predicated by "if this is the absolute frame") while STR makes absolute ones

On that note, it seems that if LET asserts that, then lacking a frame that satisfies the requirements of the interpretation, the interpretation must be false. Oh sure, it works under Minkowski flat spacetime, but the universe is not modeled by that kind of spacetime. No known coordinate system orders all events in all of spacetime, so any theory that asserts such an ordering must be false.
Notably, an inertial coordinate system behaves empirically different than the universe we observe.  Secondly, while there are some coordinate systems that can objectively order all events inside and outside an evaporating black hole, but none do so for more than one black hole.

Suppose I drop a clock into a large black hole. It reads midnight when it passes the event horizon.  One event is that clock when it reads one second past midnight.  Another event is a point in normal space near where that black hole finished evaporating an hour ago.  Which event occurs first and where along the worldline of the later clock is an event simultaneous with the earlier event?  Assume any method you like for the objective frame, but one must be chosen. The lack of a candidate coordinate system means there cannot be an objective one.

[David Cooper]

The red dot (representing a clock) travels in circles around the white clock.

And there's your problem. Circular motion requires continuous acceleration towards the center of the circle, so there is no symmetry between an orbiting twin and a stationary one.

The whole point of this example is that the circular motion is eliminated by the other clocks forming a relay race round the same circuit with them all moving along straight paths and confirming that the acceleration is irrelevant: it shows the case with acceleration to map with high precision to the case without acceleration, and if you want higher precision, you just add more clocks to the relay to have the polygon tend to the circle.

[David Cooper]

The two theories do make identical predictions. Dave has a long history of creating straw man arguments against SR, such as the statement below:

That is incorrect. They make predictions that are mathematically distinct because LET's predictions are all conditional. It's a key difference. In LET it is incorrect to make those predictions in LET without the conditions. There are some predictions made by LET and STR which are identical because they always produce the same answers for all frames, such as those about the timings that will be made by clocks between passing one object and then later passing another.

LET makes conditional predictions (meaning that they're all predicated by "if this is the absolute frame") while STR makes absolute ones

On that note, it seems that if LET asserts that, then lacking a frame that satisfies the requirements of the interpretation, the interpretation must be false.

It doesn't lack such a frame - we just can't tell which one it is. You've moved on into such broken physics that I'm not going to bother commenting on it beyond saying that Spacetime generates event-meshing failures all over the shop: it's not sustainable science and it's being torn to shreds on Quora, the one place where it can be discussed properly without censorship. The establishment defenders simply have no moves to counter with: they've been fully exposed and found wanting.

[David Cooper]

The reality is that you're doing anti-education and it's unethical. You are pumping out disproved propaganda instead of doing real science. This is real science:-

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.

So what do they do? Delete it. Move and hide it. Ban the real educators. That's what they do. That's what you do. It's immoral, and you can't get away with it forever.

[Kryptid]

Einstein's insistence that the speed of light is always c relative to any observer is nothing more than a contrived mathematical abstraction

If that was true, then why have attempts to measure light's speed in a vacuum always resulted in c regardless of the technique we use?

[alancalverd]

The whole point of this example is that the circular motion is eliminated by the other clocks forming a relay race round the same circuit with them all moving along straight paths and confirming that the acceleration is irrelevant: it shows the case with acceleration to map with high precision to the case without acceleration, and if you want higher precision, you just add more clocks to the relay to have the polygon tend to the circle.

Oh dear.

[Jaaanosik (OP)]

Hi all,
here is a question for everybody.
A train observer on a train car with L'₀=3.4641cs' sends a light beam towards the front of the train car.
Is the light beam going to cross 3.4641cs' in 3s' of the train reference frame?
Jano

[Colin2B]

@David Cooper
David, don’t have a problem with you discussing LET vs SR, but as you know we do segregate new/alternative theories so I’ll move this to allow full discussion.

[Jaaanosik (OP)]

Colin,
this thread is not about LET.
Why did you move it?
Jano

[Halc]

Colin,
this thread is not about LET.
Why did you move it?
Jano

The OP is enough for that (the part in bold).  OK, it was worded as a question, not as an assertion, but you're not open to pretty much a unanimous answer to the question, so it seems best that this thread is here.

Length contraction being real or not depends on one's definition of 'real'.  Is 5 being closer to 7 than to 2 'real'?  Ambiguous question without a definition, but 5 seems by any reasonable line of thinking to actually be closer to 7 than to 2, so I'd generally guess 'yes'.

Similarly, length contraction is real because if it were not, different measurements would result, such at the time it takes light to traverse to the end of a moving object and back. But that's using my definition of 'real'.

I do agree that it is your thread and not about LET, so not sure why the title needed to be changed.

[Jaaanosik (OP)]

This is the definition of reciprocal in my view.
Do we have an agreement?

No, we do not. Your diagram doesn’t make sense, nor does it define reciprocal.

Colin,
Please, fix the subject of the thread.



Fair enough, here is a description.
The left origin of the blue arrows is an event A where x=x'=0 and t=t'=0.
2s in platform frame are required for the red arrow up 90 degree.
... but 1s for the blue arrow to go up 90 degree.
This is the relativity, right?
Jano

[puppypower]

I invented an exercise regimen called the Special Relativity Work Out; SRWO, about 10 years ago. This patent pending exercise regimen is a way to burn calories, like you are exercising, but without exercising. it is based on a relative reference effect often used when discussing SR and the universe. 

The way it works is my company has a professional runner on staff, who runs around a track. The paying clients recline in chairs, at various points along the track. I then hypnotize them and have them all pretend that the pro runner is stationary, and we are all moving, I have them more their arms. Since reference is relative to the observer, and there is no preferred reference, all the clients are now in relative motion without having to actually move. They burn calories. The runner by being stationary, burns much fewer calories, base on the consensus of the majority reference. This allows him to run for hours without getting tired. I feed him one grape per hour.

This exercise regimen is used throughout astral physics, where we are told reference is relative to observer and there is no preferred or no absolute runner reference in the universe. The SRWO i backed by physics.

The reason this premise can work in physics is we see the universe based on visual or light-energy type evidence. We cannot touch the materials of the universe, like the mass of a distinct galaxy. But we can see its various lights and infer things from that based on our relative reference.  Based on this scientific approach, I place the chairs around the track, so the clients  can see the runner's light emissions, but they cannot touch the runner either. Since physics says this result in no preferred reference, everyone burns calories just for showing up and believing. I have applied for an intergalactic patent pending.

When Einstein developed SR he purposely used three parameters, mass, distance and time. Mass is the only tangible thing among the three parameters. If I throw a rock of mass=M at you, it will hurt. Mass via GR can bend space and time.

Distance and time are more like reference variables. I cannot throw distance or time at you and make it hurt. It is more in the mind and imagination game. Since the mass, which is the  only real substance is left out, by default, since the energy signals come to us faster and are easier to use, we only use two of the three SR variable and infer the masa and relativistic mass. We cannot do a proper energy balance without the actual tangible mass. The mass would give us the preferred reference sequence by allowing us to compare relative reference claims via an energy balance of the substance that emits the light.

This science support is why the SRWO is such a success; backed by science.