Gary Stephens

I read the two references you supplied more carefully and now I understand the source of your confusion.

Note that Einstein's book and the animation do not depict the same situation. That is the reason they reach different conclusions.

In Einstein's explanation, B took place earlier than A but the opposite happens in the animation. Regarding your statement:

"So either Einstein's description of what the observer in the carriage would see is wrong, or the animation showing the light rays reaching the middle of the carriage is wrong"

The answer is that both are correct because they describe different situations. In Einstein's description, A and B flashes happen simultaneously for the observer in the embankment while in animation the flashes are simultaneous for the observer on the moving train.

Dear Gary Stephens ,

some time ago I prepared this in order to have a clearer idea on what is really happening in the embankment and in the train.

Preprint Breaking the Lorentz invariance, no Relativity of simultaneity ?

Light goes at the same speed if emitted from the embankment or emitted from the train what changes is the frequency detected due to the Longitudinal Doppler.

There is a triviality in all this:

light does not sum up with the speed of the train (same as speed of sound) Beams departing at once from the same position (which is possible) but from sources at different speeds will strike to the same target at once.

As seen from the embankment, light sent in opposite directions reaches first one side of the wagon for sure.

Dear Professor Lambare,

You raise a very interesting point.

But surely, motion is supposed to be 'relative' in special relativity, and so the animation and Einstein's description should be equivalent?

We could have, for example,

situation 1) both the embankment and the train are stationary : the flashes meet in the middle M at the same time. and

situation 2) the embankment is moving uniformly to the left, while the train is left stationary. In which case, again : the flashes meet in the middle M' at the same time.

In the second case we are calling the middle M' to indicate the moving frame of the observer.

But surely, this is equivalent to the train moving, and the embankment stationary, as in Einstein's description?

But surely, this is equivalent to the train moving, and the embankment stationary, as in Einstein's description?

No, because clocks that are synchronized in one system are not synchronized with respect to the other. In other words, you have to assume from the beginning who sees the fashes simultaneously.

Dear Professor Lambare,

So you are saying the observer situated at M', as Einstein says, will not see the rays reach him simultaneously, whereas the observer at M will see the rays reach him simultaneously?

The observer in both cases being the same man?

- The observer in both cases being the same man?-

No, you have two different observers in relative motion, they can't be the same man.

Another usual confusion is the belief that they observe different realities, they observe only one objective reality but they assign different spacetime coordinates to the same reality.

Einstein's book describe a different reality than Norton's, that's why you cannot compare them directly. In Einstein's book the stationary observer in the embankment sees the events simultaneosly thefore in "this reality" those events are not simultanous for the observer in the train.

In Norton's case the observer in the train sees the flashes simultanously, therefore "in this other reality" (different situation, phenomen, etc.) for the stationary observer, the events are not simulaneous.

You have only one phenomenom or situation. You cannot have both at the same time, it is either what Einstein describes or what Norton does.

The problem with the relativist deniers is that they elevate Newton's absolute time to an apodictic or analytic truth, i.e., something that is imposed by logic and which rejection is inconsistent.

Dear Gary Stephens

Let me add a comment about relativists' deniers in general. Since they do not understand the logic behind the relativistic principles, they try to prove its inconsistency through fallacies and Sophisims that only reveal they do not actually understand. The best example of this is Dingle's objection to the twin paradox.

Cheers

Dear Professor Lambare,

"Einstein's book describe a different reality than Norton's, that's why you cannot compare them directly."

So Norton's description of the Relativity of Simultaneity is not the same Relativity of Simultaneity as described by Einstein? In that case why didn't Norton give the alternative view, in which, according to you, we have markedly different results as to whether the man receives the light rays simultaneously or not. In Norton's presentation the man (singular) receives the light rays simultaneously in both the scenarios given.

You are saying, Norton presented only half the case?

Also, surely Dingle is correct in his statement above, about the fundamental principle of relativity,-- that motion is relative, which you seem to be "denying". (cf above) ?

Dear Professor Lambare,

What one invariably finds is that, when one brings up questions about, for example, the Relativity of Simultaneity, then, when the considerer has no coherent answer, they avert to "relativity denier" as a means to bolster their own, often confused misapprehensions.

I'm a big fan of Special Relativity, as it happens, but whether I am or not has no bearing on any discussion about any topic I would wish to discuss.

Dear Gary Stephens

You misinterpreted me in two instances:

1) You said: "In Norton's presentation the man (singular) receives the light rays simultaneously in both the scenarios given."

That is correct, in Norton's scenario for both observers, the light reaches "the man on the train" simultaneously but not the man standing still on the embankment. That was never an issue and is not in doubt.

What Norton explains is that for the man on the embankment, the flashes at A and B are not simultaneous. However, for the man on the train, those flashes are simultaneous. This has to happen precisely because both observers agree that light reaches the man on the train simultaneously.

On the other hand, in Einstein's scenario, the light beams hit the standing still observer simultaneously, not the man moving with the train. However, both cases are correctly explained according to relativity.

2) I did not say that you are a relativistic denier. I tried to explain why they are wrong. I you want to interpret my explanation as my lack of a coherent answer, then there is no problem and there is no point in discussing anymore.

I assume that you are sincere and want to understand. If you assume that I just want to lie and confuse to defend my position then it makes no sense to discuss anything.

Dear Professor Lambare,

Beg pardon, I misread your ere post : I thought "relativity denier" was directed at me, and I do believe you are, like me, trying to further a better understanding on a very difficult and confusing subject.

"

That is incorrect, Norton explains that the flashes are simultaneous for the man moving with the train. Then he says of the man on the embankment:

"What is the new observer to make of this? For the new observer, the light from A must cover a greater distance to catch up with the receding midpoint; and the light from B must cover a lesser distance to arrive at the midpoint rushing towards it. So if the two arrive at the same moment, the light from A must have left earlier than the light from B to give it greater time to cover the greater distance to get to the midpoint. That is, the flash at A happened earlier than the flash at B."

"

This is correct, but Einstein was talking in both cases about the man on the train, (not the embankment) when he said that one ray would reach him before the other, in one senario, and not in the other. If you notice in both cases, by Norton, the rays reach the traveling man and the stationary man, in the middle, at the same time.

How I am to interpret this?

Dear Gary Stephens

I am sorry, I deleted the explanation you are referring to and posted another one that I think is better explained.

Guys, Einstein was correct but incomplete. My diagram here should have clarified conclusively viz; We can only SEE light that interacts with our lens. The man in the train can't see the signal outside it, and vice versa. He could only 'track' a light pulse outside as pulse interactions charge gas particles, which then emit laterally. He does NOT find 'Proper' ('propagation') speed by doing so. He CAN then find himself abreast of the pulse emitted from A outside the train (so apparent c+v) before receiving the pulse propagating IN the train.

That's an abridged version of the DFM analysis and description, as the Fig. Do read again slowly and ask questions if not completely clear.

Dear Professor Jackson,

Thank you very much for the above diagram. I will try and figure out what it means. Can you tell me where you get your "DFM analysis and description" from? I couldn't see that word-- or I missed the phrase DFM, in Einstein's appendix? Does he mention it later on?

The thing to keep in mind at all times that will allow you to see what is going on and answer such questions correctly is that light always travels at speed c relative to an absolute reference frame (Aether if you like), regardless of the speed of another inertial frame moving through that Aether field. The Aether frame is defined by all of the surrounding masses in the Universe (Mach’s principle.

So, in an inertial reference frame that is moving through the Aether, light travels at c-v upstream through that frame and at c+v downstream. Upstream and downstream refer to the light passing through the Aether frame that is itself moving through the moving reference frame at speed v, so to an observer that

is in that moving with that frame, light moves at c-v and c+v relative to him, but the light is actually always moving at speed c through the Aether frame

Such an observer still measures the speed of light to be c in all directions in his moving reference frame because his frame is also length contracted

such that light’s travel times in orthogonal directions are still the same which makes it appear that light is traveling isotropically at c in all directions in his frame. That is an illusion though…

I have modeled all of this. Please look at the second animation on my demos page, here:

https://www.energyfieldtheory.com/demos

Dear Professor Jackson,

It is clear from the above passage that when Einstein says "Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A" he is placing this observer temporarily back on the bank, and so (because motion is relative) he is rushing toward (and away respectively) the emitted light rays.

However, if the observer is in the carriage at M', then, for certain, all he can see and know, is that two rays reach him simultaneously.

I say "for certain," because previously it is stated that :

"If an observer sitting in the position M' in the train did not possess this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of light A and B, would reach him simultaneously, i.e. they would meet just where he is situated"

And we know from A A Robb, that "Thus, according to the view here adopted, the only really simultaneous events are events which occur at the same place."

Meaning... these kind of events (ie. the one described above as "the two rays meeting simultaneously at the same place") are simultaneous in all frames. Hence they are also simultaneous for the observer moving in the carriage situated at M'.

The reason why Einstein misspoke, here, is, I believe, because he is thinking of two different men (one on a stationary train, and one on a moving train) and one observer looking on.

When the right way to think of it, is to have one man on the train, and two observers, or two perspectives, because motion is relative. In the second way of looking it at, it becomes more obvious that the rays must meet in the middle, at the same time, in both cases, as demonstrated in Norton's diagrams, because they are merely different perspectives of the same event that took place "at the same time at the same place."

“…Is there a misspeak in Einstein's train and embankment thought experiment, as described by Einstein in the 1952 edition of his book ?

…..if we compare this statement with the animation found here (scroll 1/4 way down) :

https://sites.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/Special_relativity_rel_sim/index.html

we notice that as far as the observer moving with the train, situated at M', is concerned,--- according to what he can possibly know (he can't know of things distant to him) -- the light flashes reach him simultaneously, and that is all he can know….”, etc.

- in this thread really the notorious “relativity of simultaneity” physical effect is considered, while the posting in the thread is till now rather vague, first of all since relates to the rather vague “explanation” in the link above.

Really there is no some weirdness in the effect, if somebody understands what the 1904 Lorentz transformation mean [though the “relativity of simultaneity” was correctly rigorously quantitatively estimated by Voigt yet in 1887]:

- since if there exist two relatively moving with a speed Vinertial reference frames – in the quoted Einstein 1952 formulation – one is “stationary” - a “platform”/ “embankment”, and other is moving in the first one - the “train”, and the instruments in corresponding the frames, i.e. the scaled rules and a set of specifically synchronized clock, are set physically correctly, i.e. in accordance with the Lorentz transformations,

- then the distant clocks always show different not only because of that the clocks have different tick rates [in moving frame clocks tick slower in Lorentz factor], but also the distant clock in moving frame simultaneously show different “times” – if the frame moves along X-axis, the clocks that are distributed along the axis show lesser and lesser “times” in accordance with the Voigt-Lorentz decrement –Vxi/c2, xi are clocks positions on the X-axis.

Besides note, that consideration of any physical situation is utmost simple, if it is considered in an absolute frame, which is fundamentally stationary in the 3D space; such frames can exist as that rigorously proven in the Shevchenko-Tokarevsky’s informational physical model

https://www.researchgate.net/publication/354418793_The_Informational_Conception_and_the_Base_of_Physics; and in absolute frames all material objects/events/effects , i.e. velocities, energies, sizes, etc., have just real values.

So if in the train flashes of light happen in the train’s [that has a length L] ends simultaneouslyaccording to the train frame’s clock showings, tb and tf, tb=tf, be directed to the train’s middle,

- then, despite that when light passes from front end to the middle end with the speed c, really the middle moves toward light with the speed V, and so “effective” light speed in this case is equal to (c+V) [and correspondingly back end light passes to the middle with effective speed (c-V),

- the flashes really hit in the observer in the middle simultaneously, in time moment tm, and, at that, correspondingly measured by clocks in the moving frames time intervals (tb-tm) and (tf–tm) are equal, the measured speed of light is equal to, say, c=L/2(tf-tm).

Since that happens in one point, that happens simultaneously for the observer in the absolute frame, who, however,

- in principal contrast to the observer in the train, who principally don’t know that he moves, believes that he is at rest and believes that measures just the speed of light, while really measures the compositions (c±V),

- sees what really happens in the train, including sees that at the flashes the clocks on the ends had different on VL/c2 time interval showings, and so really – though that the absolute frame observer saw directly – reallythe flashes were made non-simultaneously, the flash on the front end, when the clock showed “tf” really was made later than the flash on the back end, i.e. when it happened the back end clock had showing (tf+VL/c2) though at that the back clock showed tb=tf; i.e. to the simultaneity in the middle happens because of real non-simultaneity in the ends.

That’s in first approximation is all. The picture above is more complex since besides the above in the absolute frame there exist contraction of the train’s length, and slowing of the train's clocks tick rates in Lorentz factor, etc., but that isn’t too essential for understanding what “relativity of simultaneity” is.

Cheers

It is beneficial for this thread to read the following

Preprint The Theories of Relativity and Bergson's Philosophy of Durat...

5.1 Einstein’s train and platform scenario

Sergey Shevchenko As I said a few posts ago:

I have modeled all of this. Please look at the second animation on my demos page, here:

https://www.energyfieldtheory.com/demos

I have also explained what is right and wrong about the Relativity of Simultaneity in my paper here:

https://ccsenet.org/journal/index.php/apr/article/view/0/46861

Gary Stephens, "Can you tell me where you get your "DFM analysis and description" from?" It simply applies the logic of AE's corrected description. The train is a; "space (IRF) in motion within a space" , so light entering it changes speed on interaction with the glass (light does c/n through ALL glass! It then propagates at c in the TRAIN system. So they each 'see' the flash simultaneously, but they're no longer abreast when they do.

I'm amazed at the wide confusion most still show on this matter! The 'DFM' is the 'Discrete Field' model Einstein described, as confirmed by the NASA telemetry I referred to. Do ask questions on the above.

“…It is beneficial for this thread to read the following

The Theories of Relativity and Bergson's Philosophy of Duration and Simultaneity During and After Einstein's 1922 Visit to Paris , Jan 2020

5.1 Einstein’s train and platform scenario ….”

- to consider scientifically the “Einstein’s train” and “embankment” scenario there is no any necessity to use some mainstream “philosophy of Duration and Simultaneity”, since in the mainstream philosophy – and mainstream physics also, though, since the in the mainstream all fundamental phenomena/notions, first of all in this case “Matter”– and so everything in Matter, i.e. “particles”, “fields”, etc., “Consciousness”, “Space”, “Time”, “Energy”, “Information”, are fundamentally completely transcendent/uncertain/irrational,

- and so in every case, logically completely inevitably any mainstream philosopher’s “Philosophy”, if he addresses to some fundamental phenomenon/notion, in this case, first of all to “Matter” and “Time” [though to define any of the fundamental phenomena/notions above it is necessary to have the scientific definitions of all other pointed ones, so they can be really defined only together], that is fundamentally nothing else than some transcendent, and so unscientific, mental construction,

- while for really scientific consideration of this scenario it is enough to be able to think logically, and, at that, to understand also what at least the Lorentz transformations are. Correspondingly the complete, and quite clear for any normal human, scientific description of what really exists and happens in “Einstein train” and, simultaneously, on the “embankment” see yesterday SS post above.

Dear Declan Traill,

- as to

“…Sergey Shevchenko As I said a few posts ago:

I have modeled all of this. Please look at the second animation on my demos page, here:

https://www.energyfieldtheory.com/demos...”

- thanks for the notification, but I know what is “relativity of simultaneity”; and ,used to, physical information obtain in textbooks and scientific papers. So sorry, but I didn’t look at the animation attentively enough, and so cannot comment that; and only a minor notion to

“… I have also explained what is right and wrong about the Relativity of Simultaneity in my paper here:…”,

- that is a bit strange claim. When, yeah, it is possible to explain “what is right” in some concrete scientific, i.e. correct, view on some concrete scientific problem, in this case in the Voigt-Lorentz relativity of simultaneity problem,

- however it is principally impossible to explain “what is wrong” - in principal contrast to “what is right”, what can be principally only unique, there can exist infinite number of “what is wrong”. Nobody can embrace this infinity completely, even of all, what is written, mostly by a dozen of very vivid posters in many posts in the RG threads.

Cheers

Peter Jackson

Dear Professor Jackson,

"So they each 'see' the flash simultaneously, ..."

So to translate, you are saying, that, in both cases, the man on the train "sees" the light reach him simultaneously?

Once when he is stationary (or deemed stationary) and once when he is journeying to the right (or deemed to be journeying to the right).

This flatly contradicts Einsteins statement about the latter (the man journeying to the right, or deemed to be journeying to the right) that :

"Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A."

So Einstein is wrong on this specific point? ---or rather miss-spoke, but, he corrected himself later on in 1952? Is that about the long and the short of it?

(I do find what you are saying very interesting-- about the " a space in motion within a space"-- and I did read that in Einstein's appendix. I should really read the rest of it.)

Gary Stephens, Not only the light from front & rear, but also simultaneously with the man on the platform. However during the light transit time the man on the train has MOVED so they're no longer abreast. What Einstein missed before his '52 correction, and all other miss, is that the man in the train can ONLY see the pulse IN the train, and vice versa. We can't 'see' a signal which passes us by! (DFM).

Peter Jackson

Dear Professor Jackson,

---> " is that the man in the train can ONLY see the pulse IN the train"

This sounds a bit like sophistry to me.

Are you saying he can't see the pulses OUTSIDE of the train? What does this mean?

The reason why the light rays must arrive at the moving man, and the stationary man, simultaneously, in both cases, is a) because they can be designated to be the SAME man, with observers either stationary with the man, or moving to the left with respect to the man, who is now (because of the relativity of motion) moving to the right, and b) this SAME man is observed by both observers from afar (one stationary with the man, and one moving to the left with respect to the man,) and these observers must witness the same event happen to this single man. This event is the simultaneous arrival of the light rays.

So it hinges around a reality requirement for the observers-- they both must witness the same reality. We can't have two realities, at least not in this simple scheme.

(We might be able to have two realities in other more complex schemes, as I have outlined elsewhere.)

Peter Jackson

Dear Professor Jackson,

---> "However during the light transit time the man on the train has MOVED so they're no longer abreast"

Are you saying the lengths of the optical lines, one at the left of the carriage, one at the right of the carriage, have different lengths?

This would fit in with A. A. Robb's statement :

"Further there are certain lines (which I have called ‘optical lines’) for which the conception of length partially, but not entirely, breaks down."

Gary Stephens Did you see my post? The two links I attached give the full answer to the question of this topic. You can SEE exactly what happens in a moving inertial reference frame in the animated demo in the first of these two links...

Dear Professor Traill,

Thank you very much for your post. I did look at your website. I could not find the answer to the question-- there are some animations of cavities &c. Some exe, zip files. Beg pardon if I have missed this.

Would you be able to articulate in words, if the two rays would arrive simultaneously at (or for) the moving man? or not? ie. would you be able to explain in words, if Einstein was right in saying :

"Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A."

Gary Stephens When you say A and B, I assume you mean the two simultaneous sources of signal (lightning bolts) at each end of the train, with the observer co-moving with the train at a position mid-way down the train?

If this is correct, then the co-moving observer will receive the signal from the front of the train first, as the light from the signal will be moving through his reference frame at c+v. The signal from the other light source will be traveling through his reference frame at c-v, so will arrive after the first.

Of course, any round trip times the observer measures for light signals will appear that light is traveling isotropically at c, regardless of the actual speeds of c-v and c+v. This is because the optical path length distance between orthogonal signal directions works out to be exactly the same, due to the length contraction that also occurs in the direction of motion.

NOTE: However, this same signal timing in orthogonal directions is only exactly true in a vacuum. If the light signals are traveling through an optical medium with a refractive index greater than 1 then there is a small but measurable difference between orthogonal timings and the Aether wind speed/direction can (and has been) measured via experiments.

Gary Stephens The second animation on my Demos page shows a reference frame that is in motion through the Aether. It shows exactly how the light signals travel through that moving reference frame in each of the two orthogonal directions. You can see how the timing of the round-trip light signals is exactly the same despite the light actually traveling at c+v and c-v through the frame.

Dear Professor Traill,

Thank you! for your very definite answer. I do like answers that are definite, and given in plain speaking.

So you are saying the moving man would receive, as Einstein says, one ray before the other. I assume you would say, that for the stationary man, he receives these rays simultaneously, also as Einstein says?

And you see no problem in the light rays "actually" traveling at faster than the speed of light (c+v) with respect to the railway carriage? as a reference body?

Am I summarizing your point of view correctly?

Gary Stephens So long as the stationary observer is midway between the two lightning strikes, then yes he would observe them at the same time.

Light is never traveling faster than c through its medium (the Aether), but the moving observer does intercept the signals at a speed greater than c (and less than c from behind). This is analogous to the torch beam that is swept across the sky. The suggestion made by some is that the beam travels faster than light once one is a great distance away from the torch - but, again, the light is always traveling at speed c through the Aether field, despite the beam covering a distance at a rate greater than c. The requirement is that no energy/signal can travel faster than c through space. This is still observed.

Another way to think about it is this: The speed limit on a highway is 100 km/hr, so two cars traveling in opposite directions are each traveling at 100 km/hr and not breaking the speed limit, but their closing speed (between the two cars) is 200 km/hr.

Dear Professor Traill,

Yes I meant, as you said, in both cases the man is standing in the middle of the plank of wood/train carriage, as described in Einstein's text.

So, as far as the man at the middle of the moving carriage is concerned, light is passing him at c+v and c-v, respectively?

If so, what about Maxwell's equations which seem to fix the speed of light at c?

Doesn't that contradict what the man is witnessing, having the train as his "world".

Gary Stephens Light will be traveling according to Maxwell's equations in the Aether (background frame). In the moving frame, these same Electromagnetic waves will exist but must undergo Lorentz Transformations to see how they appear to the co-moving observer. However, as I pointed out before, any measurements made by that co-moving observer on signals within his own reference frame will appear to be 'normal' (i.e. not Lorentz Transformed and according to Maxwell's equations). This is because round-trip timing is maintaining the illusion that light is traveling isotropically at c in his frame. This is why it has been so difficult to figure this all out, and why Einstein got it wrong about the constancy of the speed of light to all observers.

Please look a the first demo on my demos page and see that for a moving laser cavity, the stationary observer and the co-moving observer see different EM waveforms, but the apparently normal EM waveform in the moving laser cavity is actually oscillating at a slower rate. This is the cause of the Time Dilation effect.

https://www.energyfieldtheory.com/demos

Dear Professor Traill,

But, as far as I know, Maxwell's equations specify that light travels at c, period. Maxwell does not mention 'round trip timing'.

---> "In the moving frame, these same Electromagnetic waves will exist but must undergo Lorentz Transformations to see how they appear to the co-moving observer."

Okay, so are they travelling at c+v and c-v, or not? You previously said that to the man in the middle, they would be traveling at c+v and c-v respectively. Now you say they have to be modified? "to see how they appear".

---> "However, as I pointed out before, any measurements made by that co-moving observer on signals within his own reference frame will appear to be 'normal' (i.e. not Lorentz Transformed and according to Maxwell's equations)"

Or

---> "any measurements made by that co-moving observer on signals within his own reference frame...will appear to be... according to Maxwell's equations"

By "according to Maxwell's equations" you mean travelling at c. But this contradicts your prior statement about them traveling at c+v and c-v respectively.

---> "Einstein got it wrong about the constancy of the speed of light to all observers."

You mean Einstein, Poincare, Lorentz, Lamour, Minkowski, A A Robb, Maxwell, and Michelson and Morley, &c &c, all "got it wrong" about light speed being constant?

Dear Professor Triall,

So according to you, the moving observer,---the man on the train, see light passing him at c+v and c-v respectively, but also he sees light passing him at c (for the purposes of satisfying Maxwell's equations)?

Gary Stephens They were right that observers MEASURE the speed of light to be c, but wrong in the sense that light actually moves through a moving IRF at c+v and c-v.

There is no inconsistency: in the same way that a car on a highway sees the car coming in the other direction to be traveling at 200 km/hr relative to himself, but in actual fact both cars are traveling at 100 km/hr (i.e. within the limit).

Maxwells equations are correct for the medium in which they are propagating (i.e. The Aether frame). For any observer moving through that frame then the Lorentz Transformations must be applied to all signals he observes.

There is an illusion for the moving observer as he measures all light signals to be traveling in round trips at c, so he re-constructs the shape of all signals accordingly. If he assumed that light was traveling at c-v and c+v then he would reconstruct the waveforms differently and see what the stationary observer sees.

The last post that really answers the thread question is the yesterday SS post on 3 page, to which, though, it seems as worthwhile to add, that the relativity of simultaneity problem in the considered in the thread “Einstein's train”, where the light flashes happen simultaneously in the “train frame” according to this frame’s front and back clocks showings, really are non-simultaneous in absolute frames, where the train moves with a speed V, however the flashes arrive the middle of the train simultaneously in both frames,

- looks as rather simpler if we consider the case when flashes happen simultaneously in the middle, and further propagate to the train ends.

Though, of course, in both cases the same Voigt-Lorentz decrement in Voigt and Lorentz transformations–Vx/c2 acts, which really objectively exists and really is observable.

The other posts contain mostly rather questionable claims, as, say

“…There is an illusion for the moving observer as he measures all light signals to be traveling in round trips at c, so he re-constructs the shape of all signals accordingly. If he assumed that light was traveling at c-v and c+v then he would reconstruct the waveforms differently and see what the stationary observer sees.….”

- in round trips time moments of flash radiating and coming back, in contrast to the cases where at any measurements, not only of speed of light, distant clocks are involved, only one clock is used, and so that has no relation to the thread question.

Etc. more see the SS posts above and SS&VT papers that are linked in the posts, where, again, the physical sense of the Lorentz transformations, including why and how the V-L decrement appears.

Cheers

Dear Professor Traill,

"They were right that observers MEASURE the speed of light to be c, but wrong in the sense that light actually moves through a moving IRF at c+v and c-v."

Query---Yes but what about Maxwell's equations specifying that light travels at c-- nothing to do here with observers 'measuring' it. How do you account for Maxwell's equations being valid in your moving frame, when you have said light "actually moves through a moving IRF (ie. the train carriage,) at c+v and c-v."

So, to recap. You say light "actually" travels through the train carriage at c+v and c-v, but then you say Maxwell's equations are valid, in which light travels at a fixed speed of c.

To get around this, you then try and claim the 'actual speed' is not the 'measured speed' -- but that doesn't effect Maxwell's equations-- which specify the speed -must be- always c.

So either Maxwell's equations (and all the phenomena brought with them) are valid in the moving carriage, or your absolute space is valid in which we have c+v and c-v.

They can't both be valid at the same time.

Dear Professor Traill,

In general, I think considerers that talk about velocities, and transformations, distances, and timings are bound to get muddled and confused.

In my opinion, any conception of reality has to be based upon events alone.

The reason for this is because events are the fundamental reality mankind is aware of. They constitute our reality. Space, time, speed, and so on, are subordinate to events--- events are the reality, everything else is contrived to make these consistent among the observers.

In 'The Relativity of Simultaneity'- the event in question is the simultaneous arrival of the light rays to the man in the middle, at M', or M, of the plank of wood, (or train carriage).

These rays -have to- arrive simultaneously for the moving observer, because, if you notice in Norton's animations, they arrive simultaneously for the stationary observer.

And not 'one after the other,' as you previously stated.

Nortion's animations also demonstrate why Einstein was mistaken, when Einstein said

"Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A."

This is an impossibility. The rays must arrive at the observer situated at M' simultaneously, just as they did when the observer was stationary.

Unless you want to try and claim there are two "Relativity of Simultaneities," Norton's and Einstein's, each with different results.

Many considerers would just stare down the street in incredulity, at the thought that Einstein could be mistaken. This is the hypnotising effect of reputation.

It's not that surprising when you think about it though. This thought experiment was not actually Einstein's-- he borrowed it from Poincare (correct me if I am wrong,) and at the time in which he drafted it, his aim was only to show that two events that might be simultaneous to one observer, may not be simultaneous to another, in uniform motion with respect to the first.

In his effort to show this, he became muddled as to what the observer on the train would actually see and experience.

Sergey Shevchenko In regards to round trip times, you said "has no relation to the thread question". But, the point I am making here is that the moving observer thinks that light is moving isotropically in his moving frame because all his measurements of light (which involve round-trip timing) indicate that light is always moving at c, in any direction he chooses. This is actually an illusion - like is moving though his frame at c-v and c+v.

Gary Stephens Maxwells equations are true for Electromagnetic fields propagating through a medium. Light DOES require a medium to propagate and that medium is the Aether background frame.

For anyone who is in notion through that medium, then he sees those EM waves but they are all Lorentz Transformed.However, the moving observer thinks that light is always moving isotropically at c in his frame as every measurement he makes seems to confirm that, so when he interprets his reading of the EM signals he receives, he reconstructs the shape & timing of these signals and everything appears to be normal (see Box 3 in the first demo animation on my demos page to see this). The only difference is that all waves are moving at a slower rate (by the Lorentz factor amount) in his reconstruction.

If he realized that light was actually moving though his frame at c-v and c+v then he would reconstruct the received EM signals' shape & timing differently and would obtain the shape in Box 2 of my first demo (on my demos page). That waveform is following Maxwell's equations, but in the Aether frame (the EM waves' medium) not his own moving frame.

Gary Stephens You said:

"So either Maxwell's equations (and all the phenomena brought with them) are valid in the moving carriage, or your absolute space is valid in which we have c+v and c-v.

They can't both be valid at the same time."

But, they CAN both be valid at the same time, and they must be - that is the only way it can work!

Electromagnetic waves propagate through a medium and the Aether frame is that medium. They cannot propagate through two different media (the rest frame and the moving frame) at the same time, with different velocities.

The moving reference frame is not the same as the Aether rest frame.

The Aether rest frame is an absolute frame through which all Electromagnetic waves propagate (at speed c relative to). Any other reference frame that is moving through this frame is observing all signals Lorentz Transformed. No signals actually move at speed c in his frame - they are all moving at c in the Aether frame.

Gary Stephens Maxwell's equations ARE being observed in the moving reference frame, it is just that the medium (in which Maxwell's Equations apply) is in motion through his reference frame.

When there is a relative motion between reference frames, the Lorentz Transformations must be applied to map from one frame to another. When this is done to the signals he observes, he obtains the waveform as it appears in the stationary Aether frame.

Professor Traill,

is, I believe, leading us along a merry path (no pun intended).

He is professor and progenitor of a new doctrine, "the doctrine of double belief"

According to the "Traill" school of Natural Philosophy, the speed of light can be both c+v, c-v AND c.

His other works include, how a Tree can be both a Tree AND an elephant.

The doctrine of double beliefs has wide applicability. Central to its application is the ingenious use of the word AND, (in capitals,) to emphasize the very obvious fact that something can be something, and something else, at the same time.

Gary Stephens It is very simple - why do you misunderstand?

Cannot a car be both traveling at 100km/hr on a highway, yet have a closing speed with my car of 200 km/hr? Of course it can. The analogy is very similar.

As I said, light is always traveling at c, but in the stationary Aether frame.

Of course it is possible for an observer to have any speed (up to c), but then the light signal will be traveling at c-v or c+v relative to him.

Professor Traill says...

The analogy of a car having a speed X and a -closing speed- Y, is 'similar' to what he is trying to say. When as he full well knows, 'closing speed' and 'speed' are two quite distinct different things. So, in fact his analogy is "not similar at all".

A rather more perfect analogy would be to say we have a car having speed X, AND the same car having speed Y.

This is actually the meaning of: c-v, c+v AND c ---within the train carriage.

One point in which I do agree with Professor Traill, is that, I think the observers have to be brought into the picture.

Gary Stephens Ok, so the speed of light is c (in the Aether frame) and the closing speed of the light for the moving observer is c-v and c+v

Dear Professor Traill,

But I know what you mean. (I hope you don't mind my little 'doctrine of double beliefs'... more for humourous effect-- I write short stories).

In your scheme, I would have called it 'apparent' speed, I wouldn't have called in 'actual speed'. The 'actual speed' is that measured, as you say in the moving carriage, in which space and time are altered.

So the 'actual speed' is c, in the carriage. I think that is what you were trying to say.

Gary Stephens, As I wrote earlier the proper distinction is between 'PROPER' speed, which is speed of propagation, a LOCAL concept, & 'CO-ORDINATE' speed, which is only 'apparent,' calculated by rate of angular displacement, not just 'closing' speed, which in the case of light is inaccessible. You did remember the importance of the observer lens; Light changes speed ON ARRIVAL & interaction to c/n lens, but ALSO by the v of the lens (k') in the local background state k. It's that last part that very few have yet grasped. (The DFM papers stacked with proofs and rationales, removing anomalies & paradoxes).

Nice you keep endowing all with professorships!

Gary:

Not quite, the moving reference frame does not have its own stationary space (from the co-moving observer’s point of view). The Aether medium is constantly rushing through his frame and light is always moving at c relative to it. So that is the actual speed: c in the Aether frame. He may be blissfully unaware of this, however, as all the usual Physics of isotropic light propagation and Maxwells equations appear to be valid in his frame. This is, however, an illusion.

Gary Stephens , Your logic is correct. Declan knows I firmly disagree with his analysis. 'Proper' & 'Co-ordinate' speeds are the correct nomenclature, long established but most didn't understand how they resolve the confusion. Fluid 'space' has local 'flow' rest states, as Einstein identified in '52 and CMB analysis (& other data) confirm. It is indeed then; "infinitely many (real & bounded) spaces in motion within spaces". i.e. as well established in astrophysics; our ECRF is rotating within the ECI frame of the plasmasphere, orbiting through the 'Barycentric' IRF.

Dear Professor Traill,

Beg pardon for my ere post-- and I want this forum to be open-minded about discussing other people's idea, and when I read it back, I expressed myself poorly, and so I deleted that post.

As far as I can tell your analysis is similar to Lorentz's in which you have an absolute reference frame, and an Aether, and you make use of Lorentz transforms &c. In which case it would make sense to say the moving frame does not have its own stationary space.

It was difficult for me to understand things from your point of view, because I was approaching the problem from a "all motion is relative" point of view. This is why I was having trouble grasping what you were saying.

Dear Professor Traill,

And in support of your absolute rest frame :

Why we can't have a centre of mass for the whole Universe, and have motion relative to that, I don't know. I suppose you could have an Aether as a kind of suspension at rest relative to the centre of mass.

Gary Stephens Ok - in my last post I did say that the moving IRF doesn't have its own stationary space.

The Aether background frame is actually formed from the sum of the EM wave-functions of all of the masses in the Universe (both near and far). This is the sum of the Gravitational Potentials of the masses, so the nearby masses have more influence than the far ones, but the number of far masses is usually much greater than the nearby ones, so will usually have the greatest percentage contribution to the sum.

Thus - the absolute reference frame to which all other motion is compared will change gradually from one location in space to another. For example on either side of the expanding Universe, the Aether frame will be determined by the masses nearer by - so the Aether frame will be stationary in line with the overall expansion of space at that location (as most of the surrounding masses are expanding away from the center at that location).

I have a couple of papers that go into this in detail:

Article Special Relativity in More Detail

Preprint Calculating the Frame Dragging effect using a Classical Physics Model

Gary Stephens Incidentally, as you pointed out, I think my theory is quite similar to Lorentzian Ether Theory (LET). I only heard about this about 10 years after writing my first lot of papers on my theory. I am perplexed as to why LET was not ultimately successful in explaining thing rather than Relativity? Maybe he did not extend it enough to be able to fully explain the effects of Relativity (as I have done), or maybe he turn a few wrong turns which made it not work in cetain situations. Possibly, as the history seems to suggest, that the Aether was discarded as not being necessary as there was no way to prove it or distinguish LET from Relativity - so no need to change! However, these assertions have been shown to be false by a number of pieces of evidence that have come to light since - one being the ability to detect light speed anisotropy and the motion of the Earth through the Aether. This has been done by a number of independent researcher who all agree (within error limits) on the magnitude and direction of the Aether wind. See the following paper on this:

Article Combining NASA/JPL One-Way Optical-Fiber Light-Speed Data wi...

The thread question is completely answered in the SS posts on pages 3 and 5. The rather vivid posting of mostly two posters after these posts has rather indirect relation to the question, and, besides, though some posts contain a couple of the scientifically correct points:

- that Matter’s spacetime is absolute, what absolutely completely rigorously follows by the rigorous Proof by contradiction, from, say, the Dingle objection from the SR, where Dingle completely rigorously proves that from the SR postulates that there is no absolute Matter’s spacetime, and that all/every inertial reference frames are absolutely equally equivalent and legitimate, the evidently senseless consequence - that clocks in two relatively moving frames absolutely equally legitimately simultaneously tick slowly and fastly – follows;

- and that in the absolute spacetime some Aether so can exist, and it exists,

- this posting contains also some points that are too questionable; first of all instead of the rigorous Dingle objection , or something like from the postulates any number of really senseless consequences follow, some rather questionable grounds of that Matter’s spacetime is absolute, are pointed, what really makes the really fundamentally correct fact that the spacetime is absolute again questionable, shows that the SR is correct theory; and only some people, which have problems with understanding what physics is, can “prove” that it isn’t correct.

So a few comments to such points:

“…The Aether background frame is actually formed from the sum of the EM wave-functions of all of the masses in the Universe (both near and far). This is the sum of the Gravitational Potentials of the masses, ….” , etc.

- really the inertial reference frames are physical sets of instruments that are necessary for measurement of distances in 3D space between material objects/events/effects, and of time intervals between events that happen in Matter. Any masses, EM waves functions, gravitational potentials, etc., have no relation to formation of the frames and of aether.

“…the Aether was discarded as not being necessary as there was no way to prove it or distinguish LET from Relativity - so no need to change! However, these assertions have been shown to be false by a number of pieces of evidence that have come to light since - one being the ability to detect light speed anisotropy and the motion of the Earth through the Aether...”

- really there practically cannot be, and so weren’t, any really scientific detections of light speed anisotropy and the motion of the Earth through the Aether; while rather numerous publications, where the authors “detected” such things, have rather evident experimental flaws and really unscientific interpretations of the experimental data; from what again it follows that the SR is correct theory, etc.

More about what is the SR, why and when it is applicable, and why and when it isn’t applicable, in real physics; what is the physical sense of Lorentz transformations, what is really ultimate base on Matter – the real Matter’s ether, etc., see the SS posts on pages 3 and 5; description of the suggested yet 10 years ago experiments, where really the absolute 3D space velocity of Sun system in the absolute Matter’s space can be really measured see in https://www.researchgate.net/publication/259463954_Measurement_of_the_absolute_speed_is_possible

Cheers

Apropos : the Twin Paradox, and absolute space.

I've always thought the Twin Paradox has always been about an absolute reference frame. It's as if both twins are born into a fixed or absolute reference frame, but, in reality, (as far as I can gather,) it's actually to do with the observers themselves determining what are the "actualities" of the situation, as per below :

Dingle observes that, in the twins paradox, the aging effect is supposed to be caused by the interval in-between the initial and final acceleration of one of the observers, it's not meant to be caused by the small intervals where there is acceleration.

And in the interval whereby each observer is traveling at uniform velocity-- their motion is relative to each other, and so the effect, if there is one, should be symmetrical-- it should be the same for each observer.

In the interval mentioned above, there is no way of knowing whether one twin is moving or the other twin in moving : this has to be decided from the memory of the acceleration experienced by one of the twins. But a clock placed next to each twin would not be aware of these previous happenings.

So we see it is actually a question of intersubjectivity-- the observers have to be brought into the picture, and in effect they decide what are the "actualities".

So Dingle's and Barter's objection to Special Relativity--- as throwing up a logical impossibility-- is valid. The answer, we believe, is to bring mankind into the picture.

Sergey Shevchenko, "Dingle completely rigorously proves from the SR postulates that there's no absolute Matter spacetime, that all/every (IRF) are absolutely.. equivalent & legitimate," Is true, but the apparently; "senseless consequence - that clocks in two relatively moving frames.. legitimately simultaneously tick slowly and fastly.." Is explainable when the 'frame transition' is an acceleration.

I reproduced Hafele & Keatings finding proving it. There's also then the Doppler effect of emissions from advancing and receding clocks. There is indeed a 'fluid' medium doing the moving, and can indeed be NO 'absolute' datum, and all IRF kinetic states k ARE equivalent.

@Gary, Don't forget the objections are to the 1905 INTERPRETATION of the postulates. Einstein's '52 correction of that freed them of the paradoxes.

Dear Gary Stephens ,

>

acceleration per se does not affect the rates of the clocks.

Although I know it is pointless trying to explain this, I will once more try to explain it. Dingle objection is a sophism, why? Because it states an obvious logical contradiction that relativity does not say.

Relativity does not claim that when you compare clock A with clock B you will find that clock A is ahead of B and at the same time, clock B is ahead of clock A. If you apply the equations of relativity only one of them will show less elapsed time than the other when you objectively compare them by bringing them together.

When you explain this to Dingle followers they respond that is not according to relativity because the theory claims that motion is relative and both clocks have the same right to show less time than the other. Those who believe the last explanation is correct do not understand that relativity is not a relationist theory meaning that it is false that every motion is relative; acceleration is absolute, not relative.

I know it is not easy to understand, so it is not silly to miss the point. What is silly though is to believe that scientists are unable of rational thinking and that science is a hoax.

With the Relativistic interpretation of two space ships (A and B), the use of Minkowski diagrams is done incorrectly when they state that both A's time is running slower than B's time and vice versa (at the same time!). This is because the axes for ship A and ship B on the Minkowski diagrams are actually two different coordinate systems so one cannot just draw a line of simultaneity from one system to the other - a mapping operation must be done to draw a sensible inference on the diagram. When this is done, then we see that both ship A and B times are running slower BY THE SAME AMOUNT. Thus, their rates of time are the same. I have written a paper proving this using the Lorentz Transformations between the two Inertial Reference Frames (ship A and ship B). It is here:

Article The Problem With the Relativity of Simultaneity

Gary Stephens

Thank you Professor, my friend, for bringing this up.

Firstly, we regard theory of relativity to be correct, so we admit that simultaneity is relative, i.e., events which are symultaneous in one reference system is not symultaneous in different reference systems.

Then, regarding to what you said

"we notice that as far as the observer moving with the train, situated at M', is concerned,--- according to what he can possibly know (he can't know of things distant to him) -- the light flashes reach him simultaneously",

Actually it is not true, the light flashes reach him NOT simultaneously.

because the two lightenings happen simultaneously only according to the reference frame of the embankment, so the two lightenings happen NOT simultaneously according to the reference frame of the moving train. If the two lightening happen at different time and at the same distance, cetainly the two lightenings will reach the observer NOT simultaneously.

If we don't accept theory of relativity as correct, it will be a different story.

We also wish to keep our friends informed that special relativity is a self-consistent theory, no matter how smart you are, no matter how inventive you can be in designing thought expriments, you can never disprove the theory of relativity using thought experiments. (I personally also tried to disprove theory of relativity by inventing thought experiments in the early days and proved to be in vain). The only way to disprove theory of relativity to be incorrect(if it is flawed at all) is to use scientific facts.

Thank you very much for your kind attention.

BR

Xinghong Wang Of course, one must correct for the time of flight of the light signals to obtain the true time of emission. That is indicated on Minkowski diagrams by 45 degree lines - these are signals traveling at the speed of light.

Thank you Professor Wang,

For your very straightforward and clear reply.

I think you are forgetting your very ingenious thought experiment, (which I borrowed) in which we make the triggering of an event at M contingent on the two rays meeting, at the same time, the man at M in the middle of the plank of wood/train carriage, in the stationary frame.

Because of the relativity of motion, we can have an observer moving to the left of this scene, which is exactly equivalent of the man moving to the right inside the train carriage.

Now the man moving to the left of this scene will also see the light reach the man in the middle at M' in the moving frame, at the same time. He has to, or we would be left with two realities. One in which the event did trigger, and one in which the event did not trigger.

This is what is shown in Norton's animations.

https://sites.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/Special_relativity_rel_sim/index.html

Here, we notice in both cases, for the man on the train, either at M or M' the rays reach him simultaneously.

We also notice for the observer moving to the left (equivalent to the man standing on the bank,) then these rays are not simultaneous. (I think that is what you were thinking of). But for the man on the train, these rays reach him simultaneously.

No flaw has been found in the above reasoning. And no flaw has been found in Norton's animations.

Unless we want to suppose we have two "Relativity of Simultaneities," --- Norton's in which the rays meet the man at M' simultaneously, and Einstein's in which the rays meet the man at M' one after the other, we must conclude--- not that the whole of Special Relativity is wrong-- it isn't,--- it is all correct, ----but that, on this occasion, Einstein misspoke.

Justo Pastor Lambare , For me you've made a clear error of logical analysis, summed up in a parochial statement; "acceleration is absolute, not relative".

A body is always in some LOCAL rest state, i.e. Earth's rotating ECRF or the Spaceship heading to Mars. Within those; 'ALL PHYSICS IS LOCAL', so acceleration equally STARTS & has a rate & magnitude with respect to that LOCAL datum state. There are as AE stated "Infinitely many" such "spaces in relative motion within spaces" in the universe.

That's why in H&K's experiment, repeated by me, atoms oscillate faster when accelerated east and SLOWER when accelerated west! Also faster in less gravity. Each one has a local DFM 'State of Origin' beyond Earth, and slows when accelerated away from it.

Peter Jackson, you clearly do not understand the law of inertia. That law is the first of Newton's three laws of motion.

The law of inertia was discovered by Galileo. It is a great mystery and nobody knows why it is true but as Newton said "Hypotheses non fingo".

Inertia precludes Newtonian mechanics and SRT from being relationist theories. Relationist theories, i.e., theories that postulate that only relative motion exists in the sense that they're all equivalent, are precluded by observation.

Mach proposed an explanation for Inertia that would mean every motion is relative. Einstein liked Mach's explanation very much and at the beginning thought that GR contained Mach's principle, but he was mistaken.

All this is not a problem of logic but an empirical fact.

So your theory that "A body is always in some LOCAL rest state" though literally true, is incorrect because all LOCAL frames are not physically equivalent.

Your DFM theory would be known to be observationally incorrect even by Galileo.

Apropos : the Twin Paradox, acceleration argument.

The acceleration argument, (as noted by Professor Phillies in the Dingle question p629) ie. that one is accelerated and the other is not, ergo, we have asymmetry, is a red-herring.

We can have each twin doing a mirror image of the motion of the other ie. we can have both accelerating away for a small portion, then traveling at uniform speed to separate distant locations, then returning, identically, to the same spot. All is symmetrical in their motions. As so, we have the same dilemma as we had before, for wholly uniform motion. Which clock is supposed to be running slow?

Dear Xinghong Wang ,

In principle yes.. although some serious suspects raised in 115 years, should have stimulated some additional experiments, but it was not the case.

In many situations SR gives experimentally verified predictions but we have to understand also why....

There are basically two equivalent versions of the Lorentz Transformations on which SR is based provided since the inception (then many others were proposed) Lorentz (1904) where the transformation of time was proposed as

t'= γ-1 t - vx'/c2

and it was deduced from experiments and tested against the invariance of the maxwell equations (by the way Lorentz used x instead of x', a mistake pointed out by Poincarè).

and Einstein's (1905) where the transformation of time was proposed as

t'= γ(t - vx/c2)

a result deduced instead from the relativity principle and constant (whose target was to presere the equivalence of inertial frames).

for space it is in both cases x'=γ(x-vt)

from Lorentz' version it is easier to understand some facts:

a) Lorentz transformations do not in general reduce to classical transformations for v

Gary Stephens

in that case there is no effect the twins will show the same counting in the gauges of their clocks. To have a non negligible difference an asymmetry is needed. That asymmetry is given with a change of speed of one of the twins.

Dear Professor Quattrini,

Query----"in that case there is no effect the twins will show the same counting in the gauges of their clocks. To have a non negligible difference an asymmetry is needed. That asymmetry is given with a change of speed of one of the twins."

And so, Dingle puts it :

" special relativity unavoidably requires that A works more slowly than B and B more slowly than A — which it requires no super-intelligence to see is impossible."

is correct.

Dear Gary Stephens ,

thanks a lot but I guess here you are the professor (due to your wide range of publications), I am not..

the Devil is hidden in the details.

In the case there is a geometical symmetry of the IRFS meaning that measured from a third IRF they go at the same speed then the result is 0.

So we have at least two info: specular symmetry and same speed but in opposite directions.

The one depicted by Dingle is a formal symmetry relying only on relative speed which gives an indetermination condition, it is an ill-posed problem..

Dear Professor Quattrini,

Query-- "in that case there is no effect the twins will show the same counting in the gauges of their clocks."

But never the less, there will have been an effect, they will both have aged less, in absolute terms?

Dear Gary Stephens ,

Yes, the twins aged less in absolute sense in regard to the stationary observer which saw them approaching in a perfect symmetric way, you have three actors in this case...

In this case with inertial transformations you have the preferred frame of the stationary observer.

With the Lorentz Transformations the preferred frame does not exist so the cancelling effect is provided by the term vx/c2 ... a pure artifact in the case there is no beam exchanged.

It has to be pointed out one very important fact which distinguish the Galilean transformations and the Lorentz Tranformations.

The former relied strictly on application of signals at infinite speeds (to a good approximation), optics, to describe the relation of material bodies in mechanics in different inertial frames.

The latter relied strictly on the application of signals at finite speeds c but were specifically born to describe the behaviour of field at the base of the signals and the signals themselves, then applied also to material bodies .

In order to be coherent with the rationale of the Galilean transformations the higher order transformations covering the behaviour of light, should be able to describe the behavior of light with something else but that is not yet available...

So Dingle's objections were wrong, he showed that he did not understand the theory well enough (by the way he made the same mistake as many others including Einstein) ... He lost an occasion to write reasonable "objections" which could drive to other useful tests of the theory in order to falsify it.

Unfortunately having wiped away Dingle's "ill posed" objections, all the supporters of SR felt so strong that they did not find necessary to do any other test in order to highlight possible flaws in the prediction power of SR.

One of the biggest argument which SR puts on the table to defend the constancy of c one-way (LORENTZ INVARIANCE) which is strictly related to the equivalence of frames, is the invariance of the Maxwell Equations.

Although Lorentz invariance guarantees the invariance of M.E. ,the form invariance of the waves as well and the covariance of the fields, a different speed of light does not necessarily disattend the previous...

Infact in media the speed of light is not c but the Maxwell Equations are the same...and it is well known that light passes from different media at different speeds...

Dear Professor Quattrini,

Query---"The one depicted by Dingle is a formal symmetry relying only on relative speed which gives an indetermination condition, it is an ill-posed problem.."

and

"So Dingle's objections were wrong, he showed that he did not understand the theory well enough (by the way he made the same mistake as many others including Einstein) ."

and

"Unfortunately having wiped away Dingle's "ill posed" objections"

---------------------------------------------------------

I think you come close to the truth, when you said "indetermination condition"-- if I interpret you correctly.

What you mean is the result in this case is "indeterminate". A bit like a quantum state being neither is this state nor in that. Because, each of the observers (in their respective frames) have equal claim to be correct.

So, as I mentioned before, I think, like Quantum mechanics, the observers have to be brought into the picture, to understand what is going on. "Ecce Homo"-- Behold the man.

The last post that really scientifically answers the thread question is the SS post on page 7 (including the posts on pages 3and 5), however in the thread after this post rather strangely vivid series of rather strange posts again appeared. As, say

“…Although I know it is pointless trying to explain this, I will once more try to explain it. Dingle objection is a sophism, why? Because it states an obvious logical contradiction that relativity does not say.…”

- for any normal human, who understands what the word “postulate in a theory” means, it is quite evident that the Dingle objection by no means is some “sophism”, since relates to just main and completely specific in the SR theory postulatesthat Matter’s absolute spacetime doesn’t exist and that all/every inertial reference framers are absolutely completely equivalent and legitimate, the SR doesn’t “say” that, it postulates that,

- and so if there are two [in Dingle objection] relatively moving IRF, every observers in every IRF, if he is true believer in the SR, and really understands what is this theory, must think, if he sees some other frame that moves in his frame, that in moving frame clocks tick slower than in his frame, and so, since both frames are absolutely equally legitimate, the clocks in the frame completely equally really legitimately tick simultaneously having two different rates. If there are N >>1 relatively moving frames, every clock in every frame ticks with simultaneous N tick rates;

- and for such the observers’ [if they are true SR believers, of course] thoughts there is, of course, no any necessity to make some experiments, etc., about which it is written in the commented post above also.

So, again, the Dingle completely scientifically points to the fundamental flaw in in the SR, which so evident, that only tooo true believers cannot grasp this fact; and a lot of real physicists, including the SR true believers, understand that Dingle is right, however in this case the other well popular “relativistic belief” acts – that the SR is so weird theory, that only a couple of Super-Super Geniuses understand the SR completely, which know how to “disprove Dingle” , but this disproof is so unbelievably complex, that cannot be understood by even simply geniuses.

What is, of course, some childish belief; however only in such cases somebody can think that the SR is completely true.

More, including about what really happens in “Einstein's train and embankment”, see the indicated above SS posts.

Cheers

Dear Gary Stephens ,

If this can be of relief, I thought, some time ago, that Dingle was not so wrong, so I was wrong at that time..so no super intelligence...

Prof. Joachim Domsta showed me how quantitatively, by applying the Lorentz Transformations, the correct value of the time dilation relevant to the Twins comes out also in the case of the symmetric configuration which gives 0, as mentioned before.

Einstein stated in a paper in 1918 that the twin paradox could not be solved within Special Relativity because inertial system of reference could not provide any solution to the problem. What was required was to solve it first in GR with gravitational acceleration and then bring back the values into SR with the equivalence principle. This is what he Einstein wrote and also Dingle who, by the way ,was one of the first to study and accept SR.

Vladimir Fock dealing with the clock paradox without gravitation did not use special relativity saying that the proper time was suitable for inertial systems only, but gravitation and found the solution correctly....

Till the 70's there was the widespread idea that the paradox was actually unsolvable within SR.

One of the first to solve the paradox in SR was probably Penrose , W. McCrea replied to Dingle on the inconsistency of his claims.

The exception raised by Dingle was ill-posed because the problem does not have any solution with only one parameter: the relative speed of two inertial frames is not enough to find a time difference.. a second parameter is needed in order to fix the values of the times and it is also related to a synchronization procedure, strictly necessary if one wants to apply the transformations successfully. That parameter provides the necessary asymmetry for a time dilation to emerge.

So if Dingle had said that in reason of relative speed alone Special Relativity was unable to solve the paradox, he would have been right.

But to affirm that the paradox raised invalidate Special Relativity, this was shown not to be true.

What I just said above does not mean that SR is totally right in the solution of the twin effect, but the quantitative result which emerges from the calculations is the right one.

To my humble opinion Dingle and scientist lost a big chance to raise a quite important problem in Special Relativity, relevant to the existence itself of the space-time and the Lorentz Invariance.

The issue is on the role/existance of the "auxiliary time" of vx'/c2 born as a light time retardation. Lorentz remained strongly convinced till death that such term was an "artifact" although he could not find alternatives.

That is the term which preserves the Lorentz invariance which by the way is what wipes away the Lorentz Aether to which Lorentz was very convinced of.

That term allows the twins to start with clocks in synch and finish their journey with clocks out of synch in reason of v/c (not on v2/c2 which is a first approximation of the gamma factor).

What is described in the paper linked below is very interesting and answer to some of your questions

A twin paradox for ‘clever’ students:

https://arxiv.org/pdf/gr-qc/0511126.pdf

what emerges there, should have been tested. The value found is a pure consequence of light retardation. It does not come out without transmitting rays of light between observers (allowing a necessary desynch). That experiment would invalidate the method of calculations used by SR to solve the paradox, meaning that the paradox could not find a viable solution in SR falsifying the Lorentz Invariance for good.

Dear Professor Quattrini,

I think you have hit upon something quite important when you said there would be no effect if the motion of the twins were completely symmetrical, when they returned, but then conversely, you also stated there would be an effect, when you correctly inferred I was talking about a third actor-- the man left on the earth.

Thinking about this more deeply, isn't it the case that the effect disappears or re-appears depending on whether they meet the third actor on their return?

So isn't it the case, the whole effect is a actually caused by the observers.

Beg pardon, I haven't as yet read all of your reply.

Dear Gary Stephens

I believe you are sincere and open to thinking objectively, so I will try to explain to you why Dingle's objection to relativity is inconsistently posed and only reveals that he did not understand the most basic traits of the theory.

Dingle's objection reduces to this

"...the theory unavoidably requires that A works more slowly than B and B more slowly than A - which it requires no super- intelligence to see is impossible..."

As I explained before that is an obvious contradiction that the theory does not claim.

To understand why Dingle's objection is not consistent you have to accept two important facts a) Time in an inertial frame is measured through a net of stationary clocks that are synchronized. Synchronization is accomplished using signals of constant speed (it does not have to be light signals, you can use signals of velocity v

Why do you continue to discuss/dispute this problem? As I already posted - I have completely solved and proven this for two identical, symmetrical traveling spaceships, both of their times are dilated by the same amount. Thus, their clocks show the same time, both during the travel (once one corrects for light propagation times) and when brought back together, but both times are slower than a stationary observer in the middle. I have proven this with the Lorentz Transformations no less (upon which Relativity is built!!).

See the proof here:

https://ccsenet.org/journal/index.php/apr/article/view/0/46861

Hi Declan, thanks for your post. I did not see your calculation but I know your answer is correct for symmetical traveling twins, i.e., symetrically moving w.r.t. to a fixed IRF.

However, that is a special cas

Please look at the end of the paper (Appendix A) for the Lorentz Transformation proof. That is indisputable!

Dear Declan Traill

I only read the abstract but I believe your calculations must be correct because you said:

"If two objects are moving at the same speed through the stationary frame (but in different directions to each other) then they will have the same degree of time dilation and will thus have the same rate of time, despite the relative motion that exists between them."

That is correct. However, as I said before that is a special case and does not address Dingle's objection. Dingle's scenario is different. In Dingle's case, he compares directly A w.r.t B.

In your case, they have the same rate with respect to the clock in the stationary frame.

However, while in inertial motion, clock A is lagging behind w.r.t the "coordinate time" of frame B while clock B is lagging behind w.r.t the "coordinate time" of frame A.

That is how you compare A and B, i.e., you do not compare them directly but through the distributed clocks of the respective frames. That Dingle never understood.

In relativity you have to differentiate between proper time and coordinate time otherwise you will get very confused and nothing will make any sense.

The relativity of simultaneity has this puzzling consequence: clocks that are synchronized in frame A are not synchronized w.r.t. frame B and vice versa. All this has to be understood otherwise you will up believing Dingle.

I probably will not convince you so it would be better to stop the discussion here.

Cheers

Justo Pastor Lambare I suggest you read the actual paper - it is not very long.

The two clocks A and B on the ships do not have the same rate of time as the stationary observer - they are both running slow, by the same amount as each other...

Dear Declan I kmow that, what you are teling me is correct and accoding to relativity.

Declan I read your calculation in the appendix just to confirm what I suspected. It is correct, just one observation, I don't know why you associate -dx with -v and +dx with +v, I think is the opposite. But anyway it does not change the final result. However, I am afraid you did not understand a word of what I tried to explained before.

Justo Pastor Lambare I associated it that way because that is the way it is drawn in the diagram. The Left hand side (ship A) is on the negative side of the x -axis, hence the negative x, and it is traveling to the right - in the positive x direction so a positive v. For ship B he opposite is true.

You said "In your case, they have the same rate with respect to the clock in the stationary frame." I assumed you meant have the same rate of time as the stationary observer. Maybe you mean the same as each other, compared to the stationary observer.

In any case, this is NOT what Relativity says. In Relativity the rate of time of each ship (seen by the other ship) is determined by drawing a straight line of Simultaneity (parallel to the observing ship's c axis) to the ct axis of the other ship. This is INCORRECT as I have explained in my paper.

Even Wikipedia says this is what Relativity says to do.

@Declan, yes I meant that each moving clock has the same rate as judged by the stationary observer. That is what you calculated correctly.

Let us call A the clock moving say to the left of C, and B the one moving to the right. You caculated the rate of A and B w.r.t C and find they are equal. That is correct. That, however, does not mean that A finds B runs at the same rate of his clock A.

I know is confusing, you shoud look for help from a physics professor to explain it in front of a chalkboard.

Look, the only objective reality here is what each clock really shows. That is called proper time and has the property of being a spacetime invariant meaning that every observer finds the same value which confirms the consistency of the theory. Sorry, I am afraid I can't do more.

To undrestand all this you have to understand the differnce between t (coordinate time) and tau (proper time).

Anyway thanks to you now I realize the problem is not so easy. Prehaps I forgot how much I had to study it before grasping the point.

Justo Pastor Lambare I'm glad you agree that the rate of time of A is the same as that of B. You do realize, though, that according to Relativity there should be a time dilation as ship A is moving relative to ship B (and vice versa). The obvious problem with this assertion of Relativity is that due to the symmetry there should be no preferred frame (A or B) so which ship has dilated time and what would their clocks say if brought back together? There is clearly a problem here and this is what causes so much objection by people and leads to misunderstandings.

If the observer on ship A or B makes the CORRECT timing corrections (Allowing for time of flight of light signals) then they WILL determine that each other's rates of time are the same, not different as you continue to assert.

If you read the worked thought experiment in my paper I state that each of the two ships sends their current time to observer C who is stationary at the midpoint between A and B and the observer at C displays these two times on a screen for all observers everywhere to see. So the observe on ship A and on ship B can look at C's screen to see what the time of the other ship is at his own time. As C sees the time on both A and B and being the same rate (both slower than his own) then A and B will see the other ship's time as being the same as his own too.

Each of the observers on ships A and B sees the screen at C by light signals that move along their own lines of simultaneity (once light propagation time has been corrected for) - between A and C and between B and C. Thus, if the observation from A to C is simultaneous and the observation from B to C is simultaneous, and the screen shows A and B's times simultaneously, then all three observers are connected by lines of simultaneity - so what is displayed on the screen is simultaneous between all three observers.

My paper gives the correct equations for performing the timing corrections on a Minkowski diagrams such that these correct findings about each other's rates of times actually are. When done properly, both A and B see each other's times as being the same and at the same rate - which are both slower than C's time.

Justo Pastor Lambare Getting back to your earlier comment, you said:

"However, while in inertial motion, clock A is lagging behind w.r.t the "coordinate time" of frame B while clock B is lagging behind w.r.t the "coordinate time" of frame A."

But the coordinate time of both A and B are different from C - they both have angled ct axes in C's coordinate space thus their coordinate time follows their own ct axes. Of course these times can be represented in coordinate time in the stationary reference frame of C. Either way, they are both the same.

As I point out in my paper, it is incorrect to draw a line of simultaneity from A's position to B's ct axis (or vice versa) and say that the intersect is a simultaneous event. My though experiment in my paper (and described in my previous message) shows this to be the case. One must map from one coordinate system to the other, by use of a (fictitious if necessary) stationary frame in between them - thus the line of simultaneity form each of A and B meet at a position on C's ct axis. This line of connectivity is what connects simultaneous events for the three observers A, B and C.

Dear Gary Stephens ,

no effect means no time dilation, it does not mean that the effect does not exist, it is predicted and has value 0.

For any asymmetry a non zero value of the difference emerges according to the clock which moved faster in the inertial reference frame of the "third guy".

Since everything in Physics has to be experimentally verified, let's see what is needed to set up an experiment to detect the twin effect.

a) A and B twin clocks stationary in the lab and get synchronized with Einstein procedure such that tA=tB

b) After synchronization, A transmit to B the information of departing at the time Tstart (depart at the same time for each clock).

c) At Tstart, A departs at velocity v and B at velocity -v referred to the lab. When they meet, by comparing their gauges at zero distance tA=tB they are in still in synch. The twin effect is negligible.

d) In the case |velocity A| > | velocity B| then tAtA and tc>tB, As a matter of fact the clock stationary in the lab ticked faster.

At the end of the day there is a preferred stationary frame which is the one of the lab.

in this case you may consider the man on earth (clock C) or you may not...

Stefano Quattrini The Large Hadron Collider (LHC) is effectively a test of this scenario, as the two clusters of protons are rotating around the ring at the same speeds but opposite directions and their masses increase according to Relativistic mass increase by the same proportion (the guiding magnetic fields must account for the mass increase so we know this is happening) - so their time dilations must also be the same - QED

Declan Traill ,

their momentum increases non linearly with speed

P=mv*gamma

Yes there is no difference between the rates of the clocks comoving with the colliding protons.

In such case the time dilation with the lab depends only on the t'=gamma-1 t

hence it is first order in v2/c2

There is no room for first order in v/c effects

it is at variance with what is written in the paper ---A twin paradox for ‘clever’ students: https://arxiv.org/pdf/gr-qc/0511126.pdf

which exploits the light retardation effect.

Time dilation is one concept and is relativity of time...

light retardation is a trivial concept and is related to relativity of simultaneity

To mix these together, by making a sum of these quantities is quite likely a conceptual mistake...

While the simultaneity at a distance in SR is a matter of convention, the different of times which emerges Physics from experiments of clocks which go back in the same position is absolute, does not give a damn to conventions...