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Author Topic: Can a preferred frame of reference be identified?  (Read 6501 times)

Offline jeffreyH

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Re: Can a preferred frame of reference be identified?
« Reply #100 on: 15/08/2016 18:30:32 »
It is interesting to note the use of combined arcsine and cosine with respect to the Winger rotation. I am currently exploring similar areas but not involving relativity. I may divert my attention soon to this subject.
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #101 on: 15/08/2016 19:29:02 »
Mr. Cooper stumbled upon an interesting feature of relativity theory.

He certainly did, and he showed that different frames produce different physics.

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One day, if he learns to do SR, he may actually be able to incorporate this into his JavaScript program. I wish him the best of luck and health on this.

He's the one doing SR properly and it's other people who need to catch up with where he has moved physics on to, in particular those who imagine that an order of events at point K or M can be changed at the wave of a wand by changing frame of reference and whispering "hocus pocus".

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https://en.wikipedia.org/wiki/Wigner_rotation

Now, what's all this about? Are you trying to suggest that if I start at rest in Frame A and then race off northwards to be at rest in Frame B instead, when I then send my squares along my east-west-aligned rails which I have taken with me they will behave differently from a rocket launched from rest in Frame A to end up co-moving with my squares which are now racing along between Rails B and B2 such that they have rotated out of alignment with the rails rather than simply taking up the same rhombus shape? Well, if they do that, they're still demonstrating different physics from what we would see when running squares along between Rails A and A2 which (the rails) are at rest in Frame A - no such rotations or distortions which change the angles of square/rectangle edges occur there. However, in reality they have no choice other than to be length contracted in the NW-SW direction, no matter what kind of rotation you might be adding to them (whether rightly or more likely wrongly).

PhysBang has gone pop and is clutching at straws, but, fortunately for him, no one knows his real name so this is of no consequence - he has no need to fear about his reputation as he can discard it like a snake shedding its skin, and that leaves him free to insult and attempt to belittle a superior mind. Still, this non-collinear boost stuff is an interesting idea which we can explore properly once my program is up and running. We'll then be doing the job properly by performing all actions exclusively in Frame A before looking to see how those events appear in other frames rather than applying wrong physics in other frames in the mistaken belief that things work the same way there.

I see PhysBang hasn't shared his calculations for the arangement of things in Frame A when the rails are moving north instead of co-moving with the rhombus. I wonder if he's bothered to do them at all. Well, if not, he could always just use his existing calculations and reverse them east-west to draw the rails as they would try to align themselves if they were moving through Frame B in the opposite direction to the rhombus instead of co-moving with it - that'll make the corners stick even further out beyond the rails. Still, I'm sure he'll keep finding more voodoo to go on tricking himself into thinking that he understands how a square peg can fill a round hole. The rest of us can concentrate on doing real physics.
« Last Edit: 15/08/2016 19:53:45 by David Cooper »
 

Offline PhysBang

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Re: Can a preferred frame of reference be identified?
« Reply #102 on: 15/08/2016 22:52:27 »
Now, what's all this about? Are you trying to suggest that if I start at rest in Frame A and then race off northwards to be at rest in Frame B instead, when I then send my squares along my east-west-aligned rails which I have taken with me they will behave differently from a rocket launched from rest in Frame A to end up co-moving with my squares which are now racing along between Rails B and B2 such that they have rotated out of alignment with the rails rather than simply taking up the same rhombus shape?
No. What happens is that the rail is no longer oriented in such a way as to produce the kind of motion that you imagine. The composition of velocities and directions is not a simple linear combination.


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Well, if they do that, they're still demonstrating different physics from what we would see when running squares along between Rails A and A2 which (the rails) are at rest in Frame A - no such rotations or distortions which change the angles of square/rectangle edges occur there. However, in reality they have no choice other than to be length contracted in the NW-SW direction, no matter what kind of rotation you might be adding to them (whether rightly or more likely wrongly).
SR is different than Galilean relativity.

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I see PhysBang hasn't shared his calculations for the arangement of things in Frame A when the rails are moving north instead of co-moving with the rhombus. I wonder if he's bothered to do them at all.
I haven't bothered, since I haven't had the time to work through the Wigner rotation required.

But if you want to make an argument about SR, then I suggest that you use SR rather than just DCR. Because if you just use DCR, then you are a crank.
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #103 on: 15/08/2016 23:26:30 »
No. What happens is that the rail is no longer oriented in such a way as to produce the kind of motion that you imagine. The composition of velocities and directions is not a simple linear combination.

You've agreed with me on the rhombus shape in Frame A and I've agreed with you on where the rails will be in Frame A if they're co-moving with the rhombus, so you've got a major problem. If you move those rails the opposite way to the rhombus through Frame B, they'll slope the other way in Frame A, and if you have the rails at rest in Frame B, they'll be aligned perfectly east-west in Frame A, so you can't fix the problem of observers K and M encountering objects in an order incompatible with the rhombus fitting between the rails. You're stuffed - you've been blown out of the water and are now an irrelevance.

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SR is different than Galilean relativity.

SR and LET deal with these frames identically when it comes to how things appear in their Euclidean metrics, and I'm doing LET (which SR is forced to conform to, and that means I'm also doing all the relevant parts of SR).

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I haven't bothered, since I haven't had the time to work through the Wigner rotation required.

All you need to do is work out how those rails are aligned in the Frame A diagram, and that's no harder than any of the other things you've already worked out. Tip: there's no double boost involved, so you're barking up the wrong tree.

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But if you want to make an argument about SR, then I suggest that you use SR rather than just DCR. Because if you just use DCR, then you are a crank.

If you can't see that SR has to conform to everything I'm doing here, you're the crank. You showed that you were unable to produce a different shape for the rhombus from mine, and the way you calculated that will work just fine for calculating that the rails will cross the Frame A diagram perpendicular to their direction of travel. All you have to do then is put the rhombus over the rails and see if the corners stick out beyond the rails, which they do, at which point the observers at K and M will tell you that the objects pass you in an order incompatible with the square fitting between the rails and you realise that that order can't be changed by any valid transformation to another frame. But still you can't see that and instead go on making yourself look more and more ridiculous. If that's your speciality though, that's great - everyone should have an ambition to be great at something.
 

Offline PhysBang

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Re: Can a preferred frame of reference be identified?
« Reply #104 on: 16/08/2016 13:08:45 »
if you have the rails at rest in Frame B, they'll be aligned perfectly east-west in Frame A,
Well, no. Because of the correction for time, at any moment simultaneous in Frame A the tracks will be at an angle. This is an aspect of the relativity of simultaneity that you just aren't taking into account.

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SR and LET deal with these frames identically when it comes to how things appear in their Euclidean metrics, and I'm doing LET (which SR is forced to conform to, and that means I'm also doing all the relevant parts of SR).
I'm not sure what "LET" is supposed to be, but you are using DCR.

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I haven't bothered, since I haven't had the time to work through the Wigner rotation required.

All you need to do is work out how those rails are aligned in the Frame A diagram, and that's no harder than any of the other things you've already worked out. Tip: there's no double boost involved, so you're barking up the wrong tree.
Says the person who can't work out where the rails will be because he can't work out when the rails will be. If you are speaking of trying to sync up moving W-E in a frame moving S-N in order to get a motion that is SW-NE, then you are speaking of a double boost.

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If you can't see that SR has to conform to everything I'm doing here, you're the crank.
Yes, I agree that I am being a crank by refusing to include the time parameter and refusing to do actual transformations and instead just using a series of shortcuts.

Oh, wait, I'm not the one refusing to use SR. So who is the crank again?
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #105 on: 16/08/2016 17:37:29 »
if you have the rails at rest in Frame B, they'll be aligned perfectly east-west in Frame A,
Well, no. Because of the correction for time, at any moment simultaneous in Frame A the tracks will be at an angle. This is an aspect of the relativity of simultaneity that you just aren't taking into account.

The angle's perpendicular to the direction of travel when the rails are moving north. You are determined to try to have them co-moving with the rhombus because it's the only thing you can do to keep them aligned with the edges of the rhombus, but even if I allow you to do that, what are you going to do when I send another square NW so that it becomes a rhombus aligned the other way and doesn't fit between your tilted rails? Are you going to have the rails co-moving with that at the same time as they're co-moving with the first rhombus?

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I'm not sure what "LET" is supposed to be, but you are using DCR.

LET is Lorentz Ether Theory, as you ought to have learned as part of your training. The rules of how things behave in the Euclidean metric of a frame and how they appear in other frames is described both by LET and by SR. If the LET approach is used to create diagrams, SR must produce matching diagrams if it isn't to have objects violating the rules. For example, if you want a square at rest in Frame B to be given an eastward shove such that it's co-moving with the rhombus on the rocket, it has to obey the same rules of time dilation and length contraction so as to avoid having a different speed of light operate for it, and that means it must take up the same shape (unless it has somehow rotated, but even then it must have the same amount of length contraction and time dilation applied to it).

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Says the person who can't work out where the rails will be because he can't work out when the rails will be. If you are speaking of trying to sync up moving W-E in a frame moving S-N in order to get a motion that is SW-NE, then you are speaking of a double boost.

You know full well that the rails are not moving east or west at all, but purely north, so there is no double boost. You're turning into a troll - all you're doing now is polluting a thread by dumping your garbage in it.

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Yes, I agree that I am being a crank by refusing to include the time parameter and refusing to do actual transformations and instead just using a series of shortcuts.

Oh, wait, I'm not the one refusing to use SR. So who is the crank again?

Yet again you claim I'm not including the time parameter, and yet it's inherent to the diagrams that time is identical for every point shown on them, so you're just repeating a well-worn lie, and that's trolling. You're also flinging the "crank" word again where it isn't warranted, so again you're trolling. The transformations you want me to use are not some kind of holy cow - they are derived from something, and I derive my methods from the same source and produce identical numbers as results, so again you're trolling. Everything I'm doing, SR is required to conform with it it isn't to have more than one speed of light acting within a frame, so again you're trolling. The so-called shortcuts that I'm using are used by real SR experts as well as by me: If you have a rail at rest in Frame A and you then move it northwards such that it's in rest in Frame B, it maintains its east-west alignment because every part of it is accelerated at the same time by Frame A's clocks and by Frame B's clocks which are all synchronised in the east-west direction such that no tilt can be imparted to the rail during this acceleration - you don't need to reach for a calculator to work that out.
 

Offline PhysBang

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Re: Can a preferred frame of reference be identified?
« Reply #106 on: 16/08/2016 18:06:46 »
The angle's perpendicular to the direction of travel when the rails are moving north. You are determined to try to have them co-moving with the rhombus because it's the only thing you can do to keep them aligned with the edges of the rhombus, but even if I allow you to do that, what are you going to do when I send another square NW so that it becomes a rhombus aligned the other way and doesn't fit between your tilted rails? Are you going to have the rails co-moving with that at the same time as they're co-moving with the first rhombus?
You aren't going to do anything, because you aren't going to work out the time coordinates. Because you are a crank.

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LET is Lorentz Ether Theory, as you ought to have learned as part of your training.
No, I have no training in being a crank; I do not know what crazy acronyms a crank is going to use.

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The rules of how things behave in the Euclidean metric of a frame and how they appear in other frames is described both by LET and by SR. If the LET approach is used to create diagrams, SR must produce matching diagrams if it isn't to have objects violating the rules. For example, if you want a square at rest in Frame B to be given an eastward shove such that it's co-moving with the rhombus on the rocket, it has to obey the same rules of time dilation and length contraction so as to avoid having a different speed of light operate for it, and that means it must take up the same shape (unless it has somehow rotated, but even then it must have the same amount of length contraction and time dilation applied to it).
And LET has to use time dilation and relative simultaneity between frames of reference just like SR does. You don't get to ignore the rules of LET.

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You know full well that the rails are not moving east or west at all, but purely north, so there is no double boost. You're turning into a troll - all you're doing now is polluting a thread by dumping your garbage in it.
The second boost is to the square, which has to get one boost to match the frame of the tracks and then to follow the tracks. Do you not realize that the square is moving relative to both frames you are imagining?

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Yet again you claim I'm not including the time parameter, and yet it's inherent to the diagrams that time is identical for every point shown on them, so you're just repeating a well-worn lie, and that's trolling.
Cranks love to claim that people asking them for the proper scientific rigor are trolling. I agree that time is inherent in the diagrams, which is why you produce bad diagrams.
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #107 on: 16/08/2016 19:19:45 »
You aren't going to do anything, because you aren't going to work out the time coordinates. Because you are a crank.

When time is the same for all objects in a Frame A diagram, the time coordinates for all points are known, and you're still trolling.

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No, I have no training in being a crank; I do not know what crazy acronyms a crank is going to use.

You clearly don't need any training in being a crank, and LET should be well known to any real expert in relativity.

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And LET has to use time dilation and relative simultaneity between frames of reference just like SR does. You don't get to ignore the rules of LET.

I don't ignore them - everything I do conforms to those rules and to the relevant parts of SR, as you found when you calculated the shape of the rhombus and discovered that I'd got it right.

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The second boost is to the square, which has to get one boost to match the frame of the tracks and then to follow the tracks. Do you not realize that the square is moving relative to both frames you are imagining?

You do not have two boosts to pin down what Rails B and B2 are doing as they're moving north through Frame A and only take an acceleration in one direction to get them from rest to relativistic speed in that direction. Likewise, you do not have two boosts to pin down what the square does when you accelerate it from rest to relativistic speed in the direction NE. You can therefore calculate with absolute ease how these items will appear in Frame A diagrams, and to claim that you need two boosts to find the arrangement of either of those rails or the rocket (with the square on it which now appears as a rhombus) is plain wrong. For a square being sent along the rails subsequently, it's another issue, but any rotation that you imagine is magically going to appear on it is going to put it out of alignment with the rails, so again that shows different physics for different frames.

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Cranks love to claim that people asking them for the proper scientific rigor are trolling. I agree that time is inherent in the diagrams, which is why you produce bad diagrams.

When you go through your fancy maths to calculate where things appear in Frame A diagrams, you produce diagrams identical to mine, or you would do if you didn't try to cheat by having the rails co-moving with the rhombus. You are a cheat, a crank and a troll.
« Last Edit: 16/08/2016 19:50:29 by David Cooper »
 

Offline jeffreyH

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Re: Can a preferred frame of reference be identified?
« Reply #108 on: 16/08/2016 21:55:08 »
MOD Stop the childish nonsense or I will lock this thread.
 

Offline PhysBang

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Re: Can a preferred frame of reference be identified?
« Reply #109 on: 16/08/2016 22:25:24 »
You do not have two boosts to pin down what Rails B and B2 are doing as they're moving north through Frame A and only take an acceleration in one direction to get them from rest to relativistic speed in that direction. Likewise, you do not have two boosts to pin down what the square does when you accelerate it from rest to relativistic speed in the direction NE. You can therefore calculate with absolute ease how these items will appear in Frame A diagrams, and to claim that you need two boosts to find the arrangement of either of those rails or the rocket (with the square on it which now appears as a rhombus) is plain wrong. For a square being sent along the rails subsequently, it's another issue, but any rotation that you imagine is magically going to appear on it is going to put it out of alignment with the rails, so again that shows different physics for different frames.
The problem with this reasoning is that it assumes that the square sent off at an angle is equivalent to the square set off along the rails of the second frame. This is not necessarily the case, since no work has been done to show that they are the same; the composition of velocities in SR is not the same as the composition of velocities in Galilean Relativity, no matter how much someone invokes "Euclidean metric" over and over again.
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #110 on: 17/08/2016 19:25:42 »
The problem with this reasoning is that it assumes that the square sent off at an angle is equivalent to the square set off along the rails of the second frame. This is not necessarily the case, since no work has been done to show that they are the same; the composition of velocities in SR is not the same as the composition of velocities in Galilean Relativity, no matter how much someone invokes "Euclidean metric" over and over again.

First you need to understand why length contraction occurs, so let's look at that now and then see how it dictates the shape that the square being sent along the rails must try to take up:-

(1) Start with four rockets sitting at rest in frame A in a square configuration. We'll call these rockets C, D, E and F, and they are sitting on the corners of a square which has its edges aligned north-south and east-west. C is sitting on the NW corner of the square, D on the NE corner, E on the SE corner and F on the SW corner. Now let's move them: all of them simultaneously (by their clocks which are synchronised for Frame A) accelerate to 0.866c northwards and then maintain that speed. Even once they are up to that speed, Frame A observers will continue to measure them as being arranged in a square formation - there has been no length contraction applied to this square, although each rocket has contracted to half its rest length.

(2) The crew on the rockets now decide to take up what looks like a square configuration to them, so C and D, the front two, slow down a little while F and E (the rear two) speed up a bit until they are satisfied that they are the right distance apart, at which point C and D speed up a bit again and F and E slow down a bit so that this correct separation can be maintained from now on. Frame A observers will now measure the formation of rockets as a rectangle which is half as long north-south as it is east-west: it is only now that it has been length-contracted to half its rest length.

(3) If these rockets are extremely small and they're crewed by tiny robots, we can have them fly over the corners of one of our standard 1m x 1m squares (made of some kind of rigid material, so let's just say it's metal - the atoms of this material are in constant communication through forces which determine their separation). C, D, E and F are now holding station over the corners of one of our squares between Rails B and B2, and it's co-moving with them as they travel directly north. We'll call this square Square B. Square B has been length contracted by its high-speed movement northwards, and the rockets have been length contracted to the same extent by trying to take up what looks to them like a square configuration. We can have another set of rockets G, H, I and J doing the same thing over a square which is at rest in Frame A, sitting between Rails A and A2, and this one will be called Square A.

(4) If we send Square A eastwards, what happens to it? (We're back to looking at the square that's at rest in Frame A.) It will length contract in the east-west direction. The Frame B view of Square A will be a parallelogram with two of its sides parallel to the rails. If we send rockets G, H, I and J eastwards too, they will also have a formation which looks like a parallelogram to Frame B observers, but this formation will not length-contract until these rockets decide to make adjustments to keep their formation looking like a square to them, and then it will contract to the same shape as Square A.

(5) Now lets do the same with our square at rest in Frame B. If we send Square B eastwards without removing the northward component of its movement, we can accelerate it to a speed which results in it co-moving with our original rocket. This rocket never had a name, so I'll now call it Rocket R - this is the rocket with a square painted on it. In different versions of the thought experiment this rocket moves at different angles through Frame A, but since I've chosen 0.866c for the northward vector of its movement, the eastward one can be 0.433 again and the square painted on it will now appear to Frame A observers as having a parallelogram shape with none of its edges aligned with the rails. That shape is the one that the material in Square B should now try to take up in order to conform to the same length-contraction that is acting on Rocket R. You are suggesting though that it doesn't need to conform to that and can hold some other shape instead, but if you try to do that there will be serious consequences.

(6) We haven't looked at what our rockets C, D, E and F do when they're given the same movement eastwards as Square B (again without losing the component of their speed taking them northwards). If C, D, E and F have not resynchronised their clocks for Frame B and still have them set for Frame A, they will all accelerate simultaniously from the point of view of Frame A observers and will remain in a rectangle formation, but since these rockets have adjusted their positions to try to make their formation look like a square to themselves, they really ought to have resynchronised their clocks for Frame B. If they've done this, rockets F and E will move off first (from the point of view of Frame A observers), while C and D will move off a moment later, and the result of this will be that Frame A observers will see their formation turn into a parallelogram with its sides parallel to Rails B and B2. This will be a mirror image of what Frame B observers see of rockets G, H, I and J accelerating off from rest in Frame A, so that makes it look as if all frames behave like a preferred frame of reference. However, when rockets C, D, E and F then try to make their formation look like a square again once they're up to speed, they are dealing with length-contraction acting on them at an angle 26.56 degrees east of north - as a consequence, they will automatically take up the same formation as the corners of the shape painted on Rocket R. Square B will attempt to take up that same shape too, and if the rails prevent it from doing so it will warp and break under the stresses being applied to it. Alternatively though, if Square B is sitting over the space between the rails rather than directly between them, it will simply adjust its shape until it matches the one on Rocket R.

You want to believe that Square B can hold some other shape than the one on Rocket R, but it can only do that if it's under stress to hold it in a shape it doesn't naturally want to take up. You believe that no such stresses will be put on it though and that it will just happily maintain a different shape from the one on Rocket B, but that doesn't work because it means you need to have a different speed of light operating across these objects, and that means breaking the speed limit for light in Frame A on Square B unless it takes up the same shape as the square painted on Rocket R. The speed of light is fixed in the Euclidean geometry of Frame A and it cannot be violated by an object behaving in ways that depend on a higher speed of light for them within Frame A.

In short, you're breaking the fundamental rules of SR by trying to have Square B take up a different shape from the square painted on Rocket R. And if you're breaking those rules because you're applying other rules that are officially part of SR, then those rules are incorrect and need to be thrown out of SR on the basis that they produce contradictions relating the the speed of light in Frame A. The fundamental rules of SR are the ones that I'm applying (the ones that were taken from LET), and they are the ones that aren't going to be thrown out.
 

Offline PhysBang

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Re: Can a preferred frame of reference be identified?
« Reply #111 on: 17/08/2016 19:51:58 »


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(3) If these rockets are extremely small and they're crewed by tiny robots, we can have them fly over the corners of one of our standard 1m x 1m squares (made of some kind of rigid material, so let's just say it's metal - the atoms of this material are in constant communication through forces which determine their separation). C, D, E and F are now holding station over the corners of one of our squares between Rails B and B2, and it's co-moving with them as they travel directly north.
Maybe. You have to establish that this does, in fact, line up this way. The composition of velocities in Galilean relativity suggests that they do, but it is not clear that this happens in SR.
 

Offline Thebox

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Re: Can a preferred frame of reference be identified?
« Reply #112 on: 18/08/2016 08:07:00 »
I've found something I didn't think would ever be possible, but it looks as if there may be a way to pin down an absolute frame of reference.

Imagine a disc lying flat with four points marked on the circumference, N, E, S and W (for the four compass directions). We will move the disc northwards in a moment while rotating it clockwise, but let's first spin it up to speed without moving it along through space. I want to spin it until the edge is moving at 0.866c relative to the centre, a speed at which length contraction should act on the edge in such a way as to halve its length. If we also sandwich our rotating disc between two non-rotating discs of equal size we can eliminate all the non-Euclidean SR distractions by imposing a tight Euclidean metric upon our rotating disc in the middle of the sandwich and use that to lay down the law about how the rotating disc must behave in that space.

We can see that there is no longer enough material in our rotating disc to fill the whole space between the non-rotating discs, so it must stretch or break. Let's assume it splits and leaves us with gap in it, the gap being much wider the further out you go from the centre as the length contraction becomes more severe. It turns out then that we're going to  need to mend our disc once it's been spun up to the target speed so as to fill in the gap, and it's only after that that will we have a complete disc rotating at our target speed. This appears to go against some of the teachings of SR in relation to the behaviour of rotating discs, but it doesn't go against the rules as to how SR works for things moving in straight lines, and we can show that the two things are actually equivalent, which means that many of the existing ideas about how rotating discs behave are wrong.

Any rocket following a tangent to our rotating disc at 0.866c must display length contraction to half its rest length, and this must be matched by the material in the edge of the disc as they move side by side for a moment. That means that the edge of the disc must appear length contracted and cannot possibly fill the space all the way round the space demarcated for it by the two non-rotating discs. We can also eliminate most of the change in direction of the material in the disc's edge by using a disc of a diameter measured in billions of lightyears across, which means that the material in the disc's edge will be moving at the same speed and in the same direction as the material in the rocket flying past at a tangent to the disc not merely for an instant, but for many hours with the material in the disc edge and the rocket potentially being side by side and only a micron apart throughout that time - this is more than long enough to rule out any role for accelerations in breaking the normal rules of length contraction and time dilation. So, we can show that a rotating disc cannot behave the way that most SR experts claim it does: it turns out that they have been breaking some of the most fundamental rules of SR.

Our next step is to move the whole disc, and we want it to move at 0.866c northwards. By the way, our non rotating discs are transparent, so we can see the rotating disc through them, and our N, E, S, W markers are printed on the non-rotating discs, so N is always the leading point of the discs as they move through space, while S is the point most aft. Once we are moving our disc sandwich along at 0.866c, the material in our rotating disc starts to behave in unexpected ways, bunching up as it moves slowly past point W and whipping back past point E with all length contraction removed there. At point E the material is not moving in the frame of reference we're using as the base for all our measurements, but at point W it is moving northwards at 0.99c and the local length contraction is to 1/7. (To calculate this speed and length contraction at point W, I imagined a rocket moving north at 0.866c and firing a missile ahead at 0.866c from its point of view, and so in our reference frame that works out at 0.99c - that rocket must behave the same way as the material at the edge of the disc where the rocket may travel alongside it for a while as it follows a tangent to the disc at that point.) Our non-rotating discs have length-contraction applying across them exclusively in the NS direction, reducing all measurements running that way to 1/2 of their rest lengths, so the discs' shapes are now elliptical with the NS diameter half the length of the EW diameter. The rotating disc should match that shape if the idea of relativity is correct, but the length contractions on the material of the rotating disc and directions in which it contracts will be different in places, and it's in exploring this that I've found something that I thought couldn't happen.

The key thing is what happens at points N and S. The material there is moving at 0.968c (which can be broken down into two vectors: it's moving north at 0.866c, and it's moving sideways at 0.433c) which means that the length contraction will make the material sit four times as close together in its direction of travel as it would do at rest, and this contraction acts at an angle of 63.4 degrees forwards of the EW line. (I worked out the 0.433c figure by thinking about how a light clock aligned EW would work here: the light in it would actually move at 60 degrees ahead of sideways, and that reduces its progress between points E and W to half, so the same halving will apply to anything else moving from E to W and back.) The component of this contraction to 1/4 is greater in the NS direction than the length contraction in the non-rotating discs at points N and S (which is to 1/2), and that's the crucial thing here - this means it must pull the rotating disc in more at N and S than the non-rotating discs, so their shapes will no longer match up in the way they do when the apparatus is not moving along through space - the sandwich filling can no longer fill the whole space between the outer discs. On the non-rotating discs we have length contraction to 1/2 of the rest length all the way from N to S. On the rotating disc we only have that amount of length contraction at the very centre of the line NS: at all other points on the line NS we have more length contraction than that (running in the NS direction). That means that SR must have a theoretically identifiable preferred/absolute frame of referrence.

Again we can send a rocket at 0.968c over point N or S at the same angle as the material of the disc there is moving to illustrate that it must contract in exactly the same way in the disc as it does in the rocket, and by giving our disc a huge diameter measured in the billions of lightyears, we can reduce all the pesky accelerations caused by the rotation to such a low level that they can be ignored (while reducing the centrifugal forces to the point of irrelevance at the same time) - the material in the disc can now be thought of as moving in almost perfectly straight lines while we're comparing its behaviour with that of the material in the rockets which are temporarily co-moving with it.

Hmm , just no, the preferred frame of reference already exists, the frame is a 1 dimensional sphere of free space. i.e the ''invisible'' whole.
 

Offline David Cooper

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Wild Goose Chase
« Reply #113 on: 20/08/2016 18:41:01 »
It's the rotation right enough: PhysBang got that one thing right (while tripping over everything else) and it looks as if it is the key to resolving everything. So, given that I may have likely misled a few people, I will now correct things and show them what actually happens.

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(6) We haven't looked at what our rockets C, D, E and F do when they're given the same movement eastwards as Square B (again without losing the component of their speed taking them northwards). If C, D, E and F have not resynchronised their clocks for Frame B and still have them set for Frame A, they will all accelerate simultaniously from the point of view of Frame A observers and will remain in a rectangle formation,...

That bit was right, and when the rockets then reorganise to make their formation look like a square to them, they would take up the same shape as the square painted on Rocket R.

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...but since these rockets have adjusted their positions to try to make their formation look like a square to themselves, they really ought to have resynchronised their clocks for Frame B. If they've done this, rockets F and E will move off first (from the point of view of Frame A observers), while C and D will move off a moment later, and the result of this will be that Frame A observers will see their formation turn into a parallelogram with its sides parallel to Rails B and B2.

And that is the rotation happening right there with the southern rockets moving off first - I thought such rotation was impossible, but I can now see that it must happen because of the way the material is distributed. So, when they adjust position to make their formation look square to them, they do take up a different shape from the one painted on Rocket R, and it is a stable one that puts the material under no stress. It takes up the same shape that the square painted on Rocket R would have if that square was painted (when at rest in Frame A) with the edges not running north-south and east-west, but rotated anticlockwise a bit (perhaps 22.5 degrees for the version of the thought experiment that involved a rhombus). When Rocket R flies over Rails B and B2 now, the shape fits between them with two of its edges parallel to the rails. At least, I think it will, but I'll have to finish writing the program to make sure.

That leads things back to the original thought experiment in post #1 with the rotating disc. If the problem is resolved for things moving in straight lines, it seems likely that it is also resolved for the material at the edge of the disc, and that's another reason to finish writing the program - I want to start with a circle and then add a series of outer rings to it by bringing rockets in to touch the edge while following tangents to the circle, the rockets of each ring moving at a higher speed, and then I want to view it from a different frame to see how some lengthen and others contract further, while some will have length contraction applied at interesting angles. On switching frame though, the timings for the rockets kissing the edge of the circle will vary and they will no longer be in a chain of contact with each other all the way round, so they'll need to lock together and then to rotate around the inner circle for some time in order to provide views from other frames that show them all linked up too. Once that is done, it should show that twice as many are needed to complete the circle where their orbital speed is 0.866c than if they were at rest.

It looks then as if relativity survives after all and I was wrong. I'll post a link to the program when it's up and running so that people can use it to explore all the issues raised in this thread.

[The argument made on my webpage still stands though - SR needs Newtonian time added to it in order to function properly, but that's a whole 'nother issue.]
 

Offline PhysBang

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Re: Wild Goose Chase
« Reply #114 on: 20/08/2016 18:59:49 »
I'm happy that by asking questions and demanding rigor we got to the conclusion that there is no problem with SR here. I'm sure that whenever "Newtonian time" is rigorously defined, it too will become a phantom.
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #115 on: 20/08/2016 20:51:35 »
There's a major problem with SR all right - it either has to have a preferred frame of reference (which merely can't be identified) or it has to allow events to change over Newtonian time at individual Spacetime locations, but that is another discussion. There's an interactive exam on my webpage which will shows people the point where they lose that argument, and no one's found a fault in that. LET will win out.
 

Offline timey

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Re: Can a preferred frame of reference be identified?
« Reply #116 on: 20/08/2016 20:54:18 »
Ah David - I see that you have come across a hurdle.  As said in pm, I didn't want to interject myself upon your thread at cross purpose to the logic of your initial concept, or put any other poster off via my involvement, but I feel that now may be the time its ok to speak.

Under the remit of reference to a Newtonian time, you say that relativity is safe.  However... SR is rather contradictory to the underlying philosophy of Newtonian time...

Since all these length contraction maths are still fresh in your mind, try this on for size if you fancy.

Dispensing with Newtonian time, create 2 scenarios where both are experiencing different SR time dilations, and state the observation each will make of the other reference frame as time frame dependent and proportional to the difference in rate of time.

With time frames missing from the observation of the other reference frame, will it appear as though a length contraction has occurred?
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #117 on: 21/08/2016 23:41:18 »
Ah David - I see that you have come across a hurdle.

It's not a hurdle - there's no way for anything to jump over it unless it can look at the universe from the outside.

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Under the remit of reference to a Newtonian time, you say that relativity is safe.  However... SR is rather contradictory to the underlying philosophy of Newtonian time...

SR and LET are both relativity theories, and any other theory wanting to compete with them will also have to be a relativity theory in order to fit in with how the universe behaves (and how we measure things in it). So long as we can't pin down a preferred frame, relativity survives (even if there is a preferred frame and some other being outside of the universe is able to tell which frame it is). SR attempts to get rid of Newtonian time, but in reality it can't function properly without it as it either generates an infinite number of contradictions or it describes universes in which the future can't be generated out of the past (depending on which version of it you want to use). There are two other models which fix these problems, but in each case they can only do so by adding Newtonian time.

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Since all these length contraction maths are still fresh in your mind, try this on for size if you fancy.

Dispensing with Newtonian time, create 2 scenarios where both are experiencing different SR time dilations, and state the observation each will make of the other reference frame as time frame dependent and proportional to the difference in rate of time.

With time frames missing from the observation of the other reference frame, will it appear as though a length contraction has occurred?

First you'll need to tell me me what a time frame is, and then you'll need to explain how they can go missing from an observation. If you have an alternative theory, you have to be able to generate the same numbers for time dilation and length contraction with it. With the program I'm writing, it will be possible to view "video" of events playing out in any frame of reference, but all the action will be be run behind the scenes in the preferred frame with time ticking at full speed there. When viewing things from other frames, you will see that events run slow in them (though no inhabitant of that universe who is at rest in that frame would realise that it's running slow), and you'll see clocks that are at rest in the preferred frame appear to run even more slowly still, even though you know they are still running at full speed behind the scenes. Whether looking at stills or "video", you will also see length contraction applied to any object that isn't at rest in the selected frame.

Everything that the program shows (or will do once it's finished) must be compatible with every viable model (even though it's based on LET under the surface), so if you want to use an SR interpretation with it, you can assert a number of different things depending on which particular SR model you want to push. With one model you can assert that time doesn't run at all, so the slowing of time in different frames is an illusion. With another model you can assert that time is running fastest for the frame you're viewing from and that all the others are running slower. With another model you can assert that time is running at full speed for all frames and that all the slowing is an illusion. All of them must agree with what appears on the screen though, the way in which time appears to run slow for other frames and how lengths appear to contract. If you have a theory of your own, it too is required to fit in with how things appear on the screen because what is shown must match up with what is measured in the real universe.
 

Offline PhysBang

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Re: Can a preferred frame of reference be identified?
« Reply #118 on: 22/08/2016 01:28:25 »
SR and LET are both relativity theories, and any other theory wanting to compete with them will also have to be a relativity theory in order to fit in with how the universe behaves (and how we measure things in it). So long as we can't pin down a preferred frame, relativity survives (even if there is a preferred frame and some other being outside of the universe is able to tell which frame it is). SR attempts to get rid of Newtonian time, but in reality it can't function properly without it as it either generates an infinite number of contradictions or it describes universes in which the future can't be generated out of the past (depending on which version of it you want to use). There are two other models which fix these problems, but in each case they can only do so by adding Newtonian time.
I'm sure that this bold and cranky claim will work out just as well as the last one. It certainly has less support.
 

Offline timey

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Re: Can a preferred frame of reference be identified?
« Reply #119 on: 22/08/2016 03:29:09 »
I read about SR and GR in relation to Newtonian time and the outside of the universe observer in Lee Smolins "The Trouble with Physics"...

I'm sure that we've touched on the matter before, last year sometime.

My model brings the phenomenon of time to reside only within the confines of the universe and it is the mechanics of the universe that cause this phenomenon of time.

My model states the phenomenon of time as being energy related.  Potential energy increases the rate of time, and kinetic energy decreases the rate of time.

(The gravity field decreasing via the inverse square law, or increasing via the square law also has an energy which I attribute to the proposed Vikki Ramsay gravitational time dilation, (previously named inverted gravitational time dilation but changed due to continued misunderstanding as to this referring something existing being inverted)).

What do I mean by time frame dependency:
OK, well to create a visual - time dilation is a change in the rate that sequential events are occurring at...
Now, imagine you are drawing a straight line vertically on a piece of paper.  I ask you to start drawing at the first bell sound, and stop drawing at the second bell sound.  I currently have the first bell in relation to the second bell set to exactly 1 standard second elapsed time...  You are also magically possessed with the ability to draw straight lines, one beside the other, on paper at a constant velocity.

I am now going to extend the time period elapsed between the first bell and the second bell each time the first bell sounds.
You are now drawing a longer straight line each time the second bell sounds.  We continue this way for 25 lines and then I reduce the elapsed time period between first bell and second bell identically reversed to how I increased it for 24 lines.

Because you are computer literate, you have of course drawn these lines on your screen.  You have 49 lines drawn side by side, the beginnings of these vertical lines form a straight horizontal line at top of screen page, and the ends of these vertical lines form a v shape at bottom of screen page.  I now ask you to align your 49 vertical lines so that the ends of the lines form an identical horizontal curve shape at top and bottom of lines.  Your 49 vertical lines should now resemble the shape of an ellipse with straight sides.

Now I am going to ask you to make marks on each of these vertical lines from top of line to bottom of line at regular intervals, so that each line resembles a measuring ruler.  Although not impossible, it is highly improbable that if you laid a ruler horizontally across these marks, that each of the 49 vertical lines 'ruler' marks would join up one after the other to create a straight horizontal line.  The marks would be aligned higgledy piggledy on the horizontal plane...
If this has resulted in a visual for you, I can start explaining observational time frame dependency:

Firstly it must be understood that in my model it is not possible for any part of the universe to travel into the future, or revisit the past, or for any part of the universe to get ahead or lag behind any other part of the universe.  We observe that time runs at different rates though and this is counter intuitive to what I just previously said...

However, I am suggesting that different rates of time can occur simultaneously to each other.  We have two people in the same place.  One person can go somewhere where time is going slower, and another to a place where time is going much faster, but when they meet up again both are in the present, and the only difference is that the person that was experiencing the faster time will have aged faster... (Yes there are a million discussions concerning the effects of journey there and journey back considerations, and of rockets not time meshing properly, but what I've said is enough to continue the observational time frame dependency explanation, so we don't need to go there)...
It would in theory be possible for a mobile phone call to take place between people experiencing noticeably different time dilations, given that GPS were extended, because both parties are, and always will remain, in the present.

Back to the diagram I had you mentally create as a visualisation:
The marks you have made at  regular intervals on the vertical lines are representative of the time frames of the differing time periods that the lengths of the vertical lines represent.  These differing time periods are occurring simultaneously...  Now place your ruler across the horizontal plane and from the top of the first line you drew, draw a horizontal line straight threw to the top of the last line you drew.  Repeat the process at each marker down the first line.  You will see that every other line of differing lengths markers will be split at intervals that have proportions that are all differing with each different length of line.

I am suggesting that the reference frame of the first vertical line you drew (representing a standard second) will only be able to view a proportion of the reference frames of the longer lines, and that the observable proportion of the reference frames of the other lines is evident in the degree of the splitting these horizontal lines are indicating between the markers you made on the vertical lines.  You will be able to repeat the process for each of the vertical lines to work out the observable proportion of the other vertical lines.

With regards to length contraction, would the proportions of the time frames of the reference frame line being observed that are not observable from another reference frames line, amount to the proportion of the expected length contraction as observed from the observing reference frames line?

Right David, I know you are really busy with your AI, which sounds as though it is gaining momentum, so I'm not expecting you to answer this imminently or anything.  I'm a bit sick of off the cuff replies in any case, and to understand this concept of an observable time frame dependency, it requires a bit of thought.
 

Offline PhysBang

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Re: Can a preferred frame of reference be identified?
« Reply #120 on: 22/08/2016 16:56:31 »
SR attempts to get rid of Newtonian time, but in reality it can't function properly without it as it either generates an infinite number of contradictions or it describes universes in which the future can't be generated out of the past (depending on which version of it you want to use). There are two other models which fix these problems, but in each case they can only do so by adding Newtonian time.
I had no idea what "Newtonian time" is in this context, despite studying Newton a lot.

According to Magic Schoolbook, "In LET the universe has three space dimensions running under a Newtonian time (which is not considered to be a dimension)..." This is just false, since time is always a dimension. What changes in SR is the relationship between the time dimension and the space dimension when applying a metric to space and time and the translations that one applies when moving from one system of coordinates to another.

Magic Schoolbook also says this false thing: "In Einstein's Spacetime, there is no real length contraction, meaning that objects aren't physically contracted by their movement through the fabric of space, and this clearly has to be the case because they can always validly be thought of as being completely stationary as all frames of reference are really equally valid."

In SR, all inertial frames of reference are equally valid, so, yes, an object in motion is length contracted relative to its length at rest for close to the same reason as in LET.

Similarly when Magic Schoolbook says this false thing: "He plays a similar trick with time, getting rid of the slowing of moving clocks too. Because all frames of reference are equally valid, a moving clock isn't really moving, so it can't actually be running slow: this too is just an illusion."

In SR, in a frame where a clock is in motion, that clock is legitimately slow.

Here is a great mistake in understanding relativity theory: "The downside to this is that such a universe could never have had its future events generated out of its past events under these rules because many of its events would have failed to mesh together properly during the generation phase (when the block was originally being constructed): a rocket which has taken a shortcut would have been unable to land on a planet which has not taken a shortcut as there wouldn't be a future version of that planet there yet for the rocket to interact with."

One of the important things about relativity theory is the structure of causality. In SR, the speed of light places limits on how things can interact. The only events in the past of a given event are those that could possibly emit light that would reach that event. The only events in the future of a given event are those events that could be reached by light that the given event could emit. The events that reside in this "light cone" are invariant across every inertial reference frame. So there is never a problem of something reaching an event that isn't there. Nothing of this relies on or demands that there is a "block universe", despite the exhortations of the proponents of the block universe model of time. There are many formulations of becoming in time in SR and GR.

One can't simply argue that this is wrong because it doesn't work like other forms of cause and effect.

What follows on the Magic Schoolbook site is, sadly, a weak version of the twin paradox. Even more sad is the claim, backed up by no citation whatsoever, that people using SR, "simply smuggle in this Newtonian time." Time and time again people are lead astray by the twin paradox and refuse to understand its resolution. In this case, the author of Magic Schoolbook simply refuses to believe that one could identify one reference frame relative to another without having some overall, preferred reference frame.

This is the kind of things that cranks say, that have an axe to grind and would rather grind that axe than take the time to learn or correct basic mistakes in laying out their diagrams: "It is quite shocking that such irrational people can hold such sway in science and that they are allowed to drown out anyone who tries to point out the glaring error in their model, but then it must be hard for them to back down even if they can see that they are wrong because they have bought so deeply into what is undoubtedly the most embarrassing mistake in the history of science. "
 

Offline timey

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Re: Can a preferred frame of reference be identified?
« Reply #121 on: 22/08/2016 17:44:11 »
Physicsbang - I rate David's magic school book site and respect the fact that he is trying to do positive things with his time, and doing it quite well, rather than sit around on the net slagging people for challenging the status quo.

Wake up dude, the realm doth not need defending!  The realm standeth in all its well deserved glory, only awaitething an even better mathematical fit.

The only way to arriveth at an even more detailed explanation of pur universe is to challenge the status quo.

Newtonian time:

https://en.m.wikipedia.org/wiki/Absolute_time_and_space

Quote:
"According to Newton, absolute time exists independently of any perceiver and progresses at a consistent pace throughout the universe. Unlike relative time, Newton believed absolute time was imperceptible and could only be understood mathematically. According to Newton, humans are only capable of perceiving relative time, which is a measurement of perceivable objects in motion (like the Moon or Sun). From these movements, we infer the passage of time."
Unquote:

BTW, the most embarrassing mistake in the history of science has got to be the geocentric model.  Just goes to show how wrong the status quo 'can' be proven.
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #122 on: 23/08/2016 00:33:59 »
Because you are computer literate, you have of course drawn these lines on your screen.  You have 49 lines drawn side by side, the beginnings of these vertical lines form a straight horizontal line at top of screen page, and the ends of these vertical lines form a v shape at bottom of screen page.  I now ask you to align your 49 vertical lines so that the ends of the lines form an identical horizontal curve shape at top and bottom of lines.  Your 49 vertical lines should now resemble the shape of an ellipse with straight sides.

If I try doing that, I see the V shape at the bottom become half as deep as it was before, and a new V shape (upside down and also half as deep as the original V at the bottom) has appeared at the top, so the overall shape is now more like a rhombus than an ellipse, but with two short extra sides at the left and right. Perhaps that's exactly what you mean though when you say "an ellipse with straight sides".

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Now I am going to ask you to make marks on each of these vertical lines from top of line to bottom of line at regular intervals, so that each line resembles a measuring ruler.  Although not impossible, it is highly improbable that if you laid a ruler horizontally across these marks, that each of the 49 vertical lines 'ruler' marks would join up one after the other to create a straight horizontal line.  The marks would be aligned higgledy piggledy on the horizontal plane... If this has resulted in a visual for you, I can start explaining observational time frame dependency:

If these marks are made at regular intervals and there are the same number on each line, the middle ones will all fall on a horizontal line drawn across the centre of the diagram, but all the others will travel at slight angles (steeper the further away from the centre line they are) and they will be made of two straight sections with a sharp kink connecting them half way across. Perhaps that isn't how you want me to draw in these markings and lines, but the most important thing that I want to see is how these relate to actual time dilation or frames of reference.

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Back to the diagram I had you mentally create as a visualisation:
The marks you have made at  regular intervals on the vertical lines are representative of the time frames of the differing time periods that the lengths of the vertical lines represent.  These differing time periods are occurring simultaneously...

I think you'll have to draw a diagram showing it the way you want me (and others) to see it, and then label it clearly to show which parts are simultaneous. Alternatively, you need to list dimensions and actual lengths of these lines and the distances between all the marks made down each line. I very much doubt that the picture I've built in my mind is the same as the one that you have in yours.

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Now place your ruler across the horizontal plane and from the top of the first line you drew, draw a horizontal line straight threw to the top of the last line you drew.  Repeat the process at each marker down the first line.  You will see that every other line of differing lengths markers will be split at intervals that have proportions that are all differing with each different length of line.

I'm visualising the V parts of the diagram at the top and the bottom having no horizontal lines running through them at all, and there are only two or three horizontal lines in total because they have to pass through the two shortest lines at the extreme sides of the diagram.

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I am suggesting that the reference frame of the first vertical line you drew (representing a standard second) will only be able to view a proportion of the reference frames of the longer lines, and that the observable proportion of the reference frames of the other lines is evident in the degree of the splitting these horizontal lines are indicating between the markers you made on the vertical lines.  You will be able to repeat the process for each of the vertical lines to work out the observable proportion of the other vertical lines.

No part of any frame of reference is hidden from view from any other frame. At every part of space, all reference frames are present and their content is fully visible from all those frames. Nothing goes unseen.

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With regards to length contraction, would the proportions of the time frames of the reference frame line being observed that are not observable from another reference frames line, amount to the proportion of the expected length contraction as observed from the observing reference frames line?

It's hard to answer that when there isn't anything that isn't observed, but the amount of time dilation is certainly proportional to the amount of length contraction. At 0.866c you have half the number of clock ticks and a reduction of length of the object (in its direction of travel) to a half. At 0.5c you have about 0.9 times the number of clock ticks and the length is reduced to about 0.9 of its rest length. What your theory needs to do though is account for things looking the same from both frames: if one observer has less time to play with than the other and that accounts for him seeing the other observer length-contracted because he's only seeing perhaps half of it, how is that going to work the other way round when the observer with twice as much time to play with also sees the first observer contracted to half his normal length? How would he be missing half the action?
 

Offline David Cooper

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Re: Can a preferred frame of reference be identified?
« Reply #123 on: 23/08/2016 01:47:10 »
I had no idea what "Newtonian time" is in this context, despite studying Newton a lot.

Timey seems to have found a clear definition of it which works for me.

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According to Magic Schoolbook, "In LET the universe has three space dimensions running under a Newtonian time (which is not considered to be a dimension)..." This is just false, since time is always a dimension.

Einstein was very keen to tell people that time is a dimension. I was under the impression that before his theory, it wasn't thought of as a dimension by anyone. I may be wrong, but it was certainly a way that Einstein tried to distinguish his theory from what had come before.

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Magic Schoolbook also says this false thing: "In Einstein's Spacetime, there is no real length contraction, meaning that objects aren't physically contracted by their movement through the fabric of space, and this clearly has to be the case because they can always validly be thought of as being completely stationary as all frames of reference are really equally valid."

It isn't false: they are always completely uncontracted in their own frame and what you measure does not tell you the truth about the hidden reality. With LET it's radically different: the length contraction is either absolutely real or its merely apparent and not real, all dependent upon whether you're measuring things from at rest in the preferred frame or from some other frame.

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Similarly when Magic Schoolbook says this false thing: "He plays a similar trick with time, getting rid of the slowing of moving clocks too. Because all frames of reference are equally valid, a moving clock isn't really moving, so it can't actually be running slow: this too is just an illusion."

If a clock runs faster at rest in one frame than a clock at rest in a different frame, you must have a preferred frame somewhere in the system which has the fastest running clocks. If you don't want a preferred frame, you are not allowed to have any real slowing of clocks for different frames - it must all be an illusion because they must all be running at full speed.

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In SR, in a frame where a clock is in motion, that clock is legitimately slow.

And when you switch frame so that you're co-moving with it, magically it becomes the faster clock. So, is it both slower and faster than the other clock at the same time? Which clock is really running slower?

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Here is a great mistake in understanding relativity theory: "The downside to this is that such a universe could never have had its future events generated out of its past events under these rules because many of its events would have failed to mesh together properly during the generation phase (when the block was originally being constructed): a rocket which has taken a shortcut would have been unable to land on a planet which has not taken a shortcut as there wouldn't be a future version of that planet there yet for the rocket to interact with."

It's your misunderstanding, not mine. That bit refers specifically to an SR model in which no clocks are allowed to run slow but where they merely appear to do so when viewed from other frames. If you want to have some clocks actually run slower than others though, you need to go for a model with a preferred frame.

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One of the important things about relativity theory is the structure of causality. In SR, the speed of light places limits on how things can interact. The only events in the past of a given event are those that could possibly emit light that would reach that event. The only events in the future of a given event are those events that could be reached by light that the given event could emit. The events that reside in this "light cone" are invariant across every inertial reference frame. So there is never a problem of something reaching an event that isn't there. Nothing of this relies on or demands that there is a "block universe", despite the exhortations of the proponents of the block universe model of time. There are many formulations of becoming in time in SR and GR.

There's no point in attacking one model by attacking it on the basis that it is a different model from the one that it is. There are four Spacetime models discussed on my page (called model zero, model one, model two and model three) and it makes no sense to attack model one by demanding that it behave like model two.

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One can't simply argue that this is wrong because it doesn't work like other forms of cause and effect.

The interactive exam was designed to force people to stop mixing up the models when commenting on them. If you think there's a fault in the argument, it is there that you have to point to it.

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What follows on the Magic Schoolbook site is, sadly, a weak version of the twin paradox.

There's nothing weak about it - I've just doubled it up so that there are two sets of twins in order to show clearly what happens with different models which are normally mixed up and confused into one incompatible mess. I then show up the problems with each model.

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Even more sad is the claim, backed up by no citation whatsoever, that people using SR, "simply smuggle in this Newtonian time."

Show me how it works without this Newtonian time then. No one else has been able to do so. They say they can write programs to simulate SR which don't cheat, but they always cheat by using Newtonian time to run one frame's clocks at a higher speed than the rest: that's a preferred frame.

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Time and time again people are lead astray by the twin paradox and refuse to understand its resolution. In this case, the author of Magic Schoolbook simply refuses to believe that one could identify one reference frame relative to another without having some overall, preferred reference frame.

If your comprehension skills were up to it, you'd notice that there is no difficulty resolving the so-called "paradox", and there never has been. Each model has a different way of resolving it though. Model zero (the static block universe model where time doesn't run) "solves" it by having everything exist eternally without the future ever having been generated out of the past. Model two solves it by tolerating event-meshing failure for a while before things settle down into the same shape as model zero. Model three solves it by having a preferred frame of reference. Model two "solves" it by tolerating impossible contradictions. You can take your pick, but models one and three are the only viable ones in the set.

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This is the kind of things that cranks say, that have an axe to grind and would rather grind that axe than take the time to learn or correct basic mistakes in laying out their diagrams:

What mistakes in the diagrams? You're at it again, making false claims about my diagrams. What they show is exactly what you get if you apply the rules of SR. But you don't own up to any of your errors. I do, and that's why I'm not a crank.

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"It is quite shocking that such irrational people can hold such sway in science and that they are allowed to drown out anyone who tries to point out the glaring error in their model, but then it must be hard for them to back down even if they can see that they are wrong because they have bought so deeply into what is undoubtedly the most embarrassing mistake in the history of science."

Sometimes I word things provocatively in order to encourage a response: that has a better chance of leading to answers from annoyed people and it helps me to correct any mistakes that I've made or to improve the wording of what I've said to clarify things and show why someone's objections are wayward. If anyone does have objections, they need to stop misinterpreting the introductory section and focus their attacks instead on the interactive exam, spelling out where it informed them that they have "failed" and then explaining why they believe they haven't failed. In response to that, I can either improve the interactive exam to deal with any invalid attacks of the same kind more clearly, or if someone ever comes up with an objection that blows the whole thing out of the water, I will change the whole thing into an endorsement of SR. My original aim was to prove to myself that SR is valid and then show other people that it works, but I have been unable to do so because it falls so far short.
 

Offline timey

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Re: Can a preferred frame of reference be identified?
« Reply #124 on: 23/08/2016 02:32:17 »
David - I'm not familiar with the term rhombus, but the shape you describe is correct...

However, the marks on the vertical lines must be made at uniform intervals on the line.  ie, the marks on all of the lines should be same distance apart. There should be more marks on longer lines...

Don't worry if the mark closest to bottom of line doesn't match the end of the line.  Its the proportionality of only 1 time frame, ie, from one mark to the next mark, being split by the horizontal lines that we use to match the markers on line 1 and line 49 that matters, and we can read this from the middle of the shape, we don't need to read the ends of lines for this part.

Although the system I'm showing you can be plugged in with numbers, we don't need to plug numbers in to understand how this works.  It doesn't matter how many vertical lines you use, or for the moment the lengths that these vertical lines are, or the distance that you make the markers apart on them, only that the shape is correct and that the distance between the markers is uniform.

When you match the markers on line 1 with the markers on line 49 and join them with horizontal lines, these horizontal lines will make divisions between the markers on every other length of line.

The divisions made between markers on each different length of line will have different proportions to each other... but the divisions made on a particular line will retain the same proportions of division from top of line to bottom. (bar any messy bottom of line marker issues)

The vertical lines are representing time periods expanding.  The markers are representing the time frames of the time period, and the divisions between markers will be representing a; the proportion of that time frame you can observe from line 1 or line 49, and b; the extent that the line, ie: rate of time you are observing, will cause the 'appearance' of a length contraction. ie: the proportion of the time frame you cannot observe from line 1 and line 49.
One side of the division will represent a, and the other b.

Some kind of fancy mathematical process of multiplying a or b by the number of spaces between the markers the line has, plus the messy remainder at bottom of line, should give the overall proportionality of a or b for an observation of that particular line, ie: rate of time, from both line 1 and line 49.

As to providing a diagram, I think I told you my laptop is broken.  Also my good phone was smashed when I got kicked by a horse last month and this one is crap.  It doesn't show me any of the diagrams you posted for instance, so if you will forgive me...
 

The Naked Scientists Forum

Re: Can a preferred frame of reference be identified?
« Reply #124 on: 23/08/2016 02:32:17 »

 

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