Do you mean the actual nature of the term γvx/c2 in LT?

Dear Justo Pastor Lambare ,

yes

Dear Stefano Quattrini

Then, I am afraid you do not understand what LT means according to SRT.

You see, LT is derived from two principles. Whatever term exists in the LT (according to SRT, not LET) is there as a mathematical consequence of those principles.

Lorentz (and others) derived their transformation to make invariant Maxwell equations. According to that, the physical content of the LT was not clear at all. Lorentz's local time was a fictitious time, a mathematical variable without physical content. Later Poincaré gave an approximate interpretation of the term γvx/c2 as a synchronization procedure.

All that story has nothing to do with Einstein's SRT and his derivation of the LT, otherwise, SRT would have been attributed to Lorentz and Poincare.

Of course, you can reject SRT, but to do it coherently, it is of no use to invent your own deviant interpretation and claim that it is wrong.

In other words, your interpretation of the term γvx/c2 in LT has nothing to do with relativity theory.

To prove me wrong and show me that it is not your own mistaken interpretation, please give one credible reference sustaining your interpretation.

Dear Justo Pastor Lambare ,

>

I quite well understand about the different way of deriving them but LT are one and the same and since the two interpretations given by Lorentz and Einstein are not equivalent at all... one of them has to represent what actually occurs in physics.

my interpretation is the one of Lorentz' , it is based on a preferred frame where light is isotropic and the term γvx/c2 as Sagnac experiment points it out, is a variation of the light-time due to the different light-path-lenghts to connect emitter and observer in relative moving frames.

First I think that we agree that such term is a time which exist for real in passing from a frame to another.

Second it is the case to agree what the interpretations of LT say, at least Einstein's.

The interpretation of Einstein of that term is a desynchronization of clocks, in sync in a frame a desynchronized in another frame at speed v (RELATIVITY OF SIMULTANEITY)

Article The case of the identically accelerated twins

That is due to the fact that Einstein theory with SOL c one-way, needs to desynchronize the clocks in the moving frame. Light should, according to that, cross the same path-length between two points set at fix distance (since it is isotropic) or rather the light time to connect A to B is the same to connect B to A.

I hope you find this in agreement with SR.

The interpretation of Lorentz which brings to the same Transformations, but avoids the space-time (but space as absolute and time separated but relative), brings to consider that, if light is isotropic in one frame, it cannot be isotropic in the other frames.

That is to say that light has a preferred frame of propagation (which on earth is the ECIF) hence the connection with light between two objects in one frame does not have the same path length if after the objects were moved to another frame. That means that the property according to which the light time to connect A to B is the same as the light time to connect B to A is complied only in one frame in a physical problem.

Stefano Quattrini

I think we mostly agree this time except for a few things.

One problem is that sometimes you state inconsistent explanations.

For instance, you cannot prove that SRT is incorrect because it assumes that light speed is isotropic. That is an assumption that should be proved wrong with experiments, not by assuming the contrary.

There is no experimental evidence to assume anisotropy of the speed of light and the existence of an ether. That is why SRT is accepted to this very day by the orthodox scientific community.

On the other hand, to make sense of Lorentz's interpretation we need a preferred frame. That frame is the frame where the ether is static. The problem with the ether hypothesis is that it is not consistent with observations. But to understand that it is inconsistent with observations you need more than one single experiment. You can always accommodate things to explain a single experiment but not to explain all of them.

Perhaps TT does not use an ether frame and it is different from Lorentz's interpretation, I do not know. But if that is the case, I will repeat a question I already asked you before. How and on what physical hypothesis do you derive the TT? Or, is it just an ad hoc modification of the LT just to eliminate ROS?

On the 'fictitious time' of Lorentz.

As I known, Lorentz's work of 1904 'Electromagnetic phenomena in a system moving with any velocity smaller than that of light ', where he introduced the 'local time', was something like reply to Poincare's work of 1900. Poincare stated that if one accepts Lorentz's concept of absolute ether with preferable frame, the action-reaction principle is broken.

Curiously but later it was found that this principle is broken in any frame (in electrodynamics). So Lorentz could don't reply Poincare.

Anyway, Lorentz showed that, using Galilean transformations of the coordinates, the Maxwell equations keep their form (are invariant). Lorentz used one assumption - on transformation of the charge density. But his assumption was based on reasonable physical arguments.

EInstein used the same assumption. Poincare used different assumption and obtained that the 'longitudinal size' of a moving charge should increase.

Lorentz gave the explanation of his 'local time': (p. 815)

It is also to be remembered that, if we wish to determine φ and a ′for the instant, at which the local time in P is t' , we must take ϱ and the vector φ , u ′ , such as they are in the element dS at the instant at which the local time of that element is t ′ − r ′/ c

It is the retarded time and therefore, its meaning is well defined.

Different interpretators of Lorentz - mostly relativists - tried to convince that this 'local time' is fictitious.

Thus, all transformations used by Lorentz are physically meaningful.

Regarding Lorentz's transformations

x' = x/\sqrt(1-(v/c)^2)

t' = \sqrt(1- (v/c)^2) *t

(Eqs. (4) and (5)),

Panofsky in Ch. 19-2, 2nd ed, gives modern explanation what Lorentz did.

Dear Justo Pastor Lambare ,

>

LT in Lorentz interpretation, which is LET , do not have ROS, pair of clocks are not seen in desync in the moving frame but SOL is not isotropic there, so it is the measured speed of light by the moving observer which is different than c.

The difference between LET and TT is in the synchronization procedures.

LT is born with internal procedure (Einstein's) while TT is born with external procedures (or also infinite signal speed). An internal procedure sets in sync pairs of clocks in all the frames with light waves at speed c. The external procedure first sets two clocks (or more) in sync in the preferred frame where SOL is isotropic, you can do it with Einstein procedure, and then disseminates the synchronization by comparing them with moving clocks two by two. That is the same as sending instantaneous signals from one clock to the other to copy its timestamp.

TT were called by Tangherlini the Absolute Lorentz Transformations in his thesis where he invented them with Schiff and Drell.

The term vx'/c2 simply disappears due to the synchronization adopted.

TT rely on simultaneity Invariance and has non Invariance of SOL.

I would say that the answer to the title question is "yes". More specifically, the relevant medium of propagation for light waves has to be Maxwell's version. The term in the time equation of the LT, as in γvx/c2, that people try so hard to eliminate, is simply explained in terms of the circumference of the tiny vortices that were involved in Maxwell's luminiferous medium. See here,

Article The Myths Surrounding Time Dilation and E = mc^2

There is a section dealing with Einstein's derivation of E = mc2. Note how he is determined to eliminate the v/c term, which of course is the very same γvx/c2 term when x = ct. That is, when the LT equations are simply the return-path longitudinal Doppler effect.

Explaining the Sacnac effect requires general relativity.

Dear Vladimir Onoochin ,

The experimental fact showing that the Lorentz Interpretation has the final word is the following:

it is an experimental confirmation based on Sagnac effect on large scale.

The GPS base station "synchronization procedure".

That is necessary to attain the famous "absolute time" t=t' which let the GPS system work with the expected precision in the ECIF.

Let's consider in fact two GPS base stations A1 and A2 set at distance H on the surface of earth along the equator.

A1 and A2 perform Einstein synchronization (by using signals propagating at c) such that A2 "copies" the timestamp of A1 (master clock).

• at t'A2 , A2 sends a light beam to A1 which replies with its timestamp t'A1,
• On receiving tA1 , A2 sets itself at tA2= t'A1+1/2(t'A2 - t'A1 ) = 1/2(t'A1+ t'A2 )
• the following H/c=1/2(t'A2 - t'A1 ) is true due to the fact that the 2way SOL in a radar measurement is experimentally c.
• After that, A1 and A2, Einstein's synchronized, an observer by using them as reference clocks will measure SOL as isotropic, such that the light time A1 to A2 is the same as A2 to A1

A1 and A2 GPS base stations are Einstein synchronized, but that is just an internal synchronization. One can set A3 in synch with A2 at distance H, but A3 will not be Einstein synchronized with A1 (because they do not belong to the same inertial frame).

That is quite different though from being synchronized in an absolute sense on ECIF which is the request of GPS constellation on ECIF.

What is needed is to reach the t=t' , so every base station "de facto" applies the SAGNAC correction wto their timestamp, which amounts to vH/c2 .

When they are in "absolute sync", the GPS base stations will detect that the light time A1 to A2 is H/c+vH/c2 while the light time A2 to A1 is H/c-vH/c2

since A1, A2 are located at distance H it comes out that

SOL = distance(A1,A2)/light_time(A1,A2) = H/(H/c-vH/c2 ) = c/(1-v/c).

Dear Stefano Quattrini ,

I am not a specialist in the problem of synchronization. But I remember a content of one lecture - the author explained a problem of synchronization of electronic clocks in a megalopolis (all clocks must show the same time). Even in conditions of a megapolis the distances (the path of moving the signal in the optical cables connecting the clocks) are essential, or the time delay due to L_{ij}/c, L_{ij} is the distance between the basic clock and the j-th clock.

Because it is difficult to determine all paths, some methods of statistics are used to compute the 'mean time'. This 'mean time' is sent to all clockes.

It is the problem of absolute synchronization. I think the synchronization between the GPS satellites is made using the same algorithm. Why? The GPS satellites move not in the geostationary orbits and not exactly over the equator. So their relative velocity with respect to the frame linked with the rotating Earth change every instant of time. It is quite impossible to write equations for all satellites even in the inertial frame. It is much easier to use the statistical approach to synchronize the satellites. It is my private point of view.

But if we consider the ideal task of motion of two satellites and the requirement to synchronize their clocks, there is one problem. The orbit of satellites is circular (not along the straight line). Formally if we go to the frame where the satellites are at rest (the rotating frame), we should make something like the LT of the Maxwell equations (at least to be sure that we correctly compute the parameters of the radio signal of synchronization, the frequency, the phase).

But as I know there is no rigorous jstification of the LT for the rotating frame. Such LT were introduced by Openheimer in 1930th.

I can mistake so if someone knows where such a rigorous jstification of the LT for the rotating frame is presented, it could be good to study it.

If I am right, it is impossible to state with sure that Einsteinian synchronization in the rotating frame gives the correct result. And it is hard to compare the 'absolute synchronization' and Einsteinian synchronization.

Dear Vladimir Onoochin ,

it is quite tricky infact its application, let's see what happens:

a) Clock A1 and A2 are set at distance H along the rim of a rotating disk at same radial distance R

b) they travel at constant speed v

c) Einstein's sync procedure is applied

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

CHECK PROCEDURE

d) A1 sends request to A2 to send its own timestamp t'A2

e) A1 in receiving t'A2 discovers that the t'A2 =tA1+H/c,

f) viceversa it is also t'A1=tA2+H/c , so according to A1 and A2 they are in sync.

so it seems that the procedure works as expected.

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

On the other hand let's continue to Einstein synchronize A3 following clock in a chain A2, always at distance H. We reach An-1 which is Einsein Synchronized with An, always at distance H. We can assume (with no loss of generality) that the distance between the last An and the first A1 (from which the time was initially copied) is also H.

mind that I was not mentioning the synchronization of satellites to obtain absolute synchronization of them. I was considering the much simpler synchronization of the GPS base stations, necessary for a common time at least on the surface of earth.

By appling the defined CHECK PROCEDURE to A1 and An (which were never synchronized with eachother) A1 is desynchronized to An (as first approximation) by vL/c2 where L= nH is the lenght of the poligon joining A1.A2. An.

The value which is found vL/c2 is exactly half the value that is found if one measure the sagnac effect for a device where light travels along such poligon arranged in two opposite rays.

We conclude that the accumulated desynchronization of clocks (which were einstein synchronized) along a close path, if these clocks move at speed v is vL/c2

What I am telling you is not a fantasy trick. You can check yourself that GPS base stations distributed on the surface of earth, which need to have a common time, for obvious reasons, Einstein synchronize and then apply such correction as a function of the direction of rotation of earth. So A1 ,a base station, will apply the correction vH/c2 after Einstein synchronizing with A2, such correction is the SAGNAC CORRECTION in GPS base station synchronization system (I am not talking about GPS satellites now). This is a consequence of the Relativity of Lorentz.

Article Relativity in the Global Positioning System

The Clocks A1 and An which underwent a Sagnac correction after Einsein Synchronization are now in absolute synchronization, same would happen if a pulse of energy (sound, light whatever) departs from the center of earth reaching at once all the clocks set around the circumference.

Dear Justo Pastor Lambare

what about Clocks that belong to the same IRF, while they are traveling in a straight line in the optical fiber and the Sagnac effect is present??

Ruyong Wang et al, “Modified Sagnac experiment for measuring travel-time difference between counter-propagating light beams in a uniformly moving fiber”, Physics Letters A 312 (2003) 7-10, DOI:10.1016/S0375-9601(03)00575-9. https://core.ac.uk/download/pdf/44141186.pdf

Dear Stefano Quattrini

The whole discussion about the Sagnac effect and special relativity can be brought to a result, if we consider intervals instead of coordinates. We know that intervals transform with the Lorentz factor, without the shift term contained in the Lorentz transformation of coordinates.

The time or space interval, subject to the Sagnac effect, is characterized by different inertial conditions on both sides of the interval. In order to quantitatively consider the impact of the Sagnac effect along those intervals, a line integral over the specific inertial conditions along the interval is necessary.

Dear Wolfgang Konle ,

Sagnac effect was measured in Sagnac experimental setup or similar, where a spinning polygon was basically involved.

Two other pieces of evidence have to be considered where the effect is present and measurable which give a big help to discriminate. In all cases, there is agreement on the delay of light of a wave of vL/c2.

that is not necessarily true at all.

a) Longitudinal motion of fiber optics kindly mentioned by James Marsen , where inertiality is involved, LT are applicable since at least for a finite time, clocks would belong to the same inertial system and then be desynced by vH/c2, .

b) GPS base stations synch procedure which involve the Sagnac correction vH/c2

Both cases involve that there is a local preferred IRF where light is more isotropic, in the case of ECIF, light is actually isotropic.

Stefano Quattrini

My claim is that the Sagnac effect used in inertial navigation systems is based upon different centripetal accelerations occuring on the different round trips of the laser light, used to sense the device orientation.

Your claim is that the Sagnac effect ist caused by path length differences between the two opposite round trips of the laser light.

Who is right? Who has the better arguments?

Dear Stefano Quattrini

I do not know what you mean by that. I can only repeat what I have already said: You never synchronize clocks in relative motion because it is against the principles of relativity. That is very clear from Einstein's 1905 paper.

You can call it a mantra or SRT if you wish.

It seems to me that you believe that readings of clocks in motion are compared by exchanging light signals or that you synchronize them by the exchange of light signals.

If you do either, then you are not talking about SRT. No wonder we have trouble communicating, we are talking about different things.

Dear Justo Pastor Lambare ,

Wolfgang Konle ,

it is just based on angular speed, an absolute effect.

Do you manage to find a term that contains ac= v2/R in the tested Sagnac relations?

I cannot...

it is not my claim, it is written virtually in every text that deals with it.

The derivation of the effect if you have the patience to read it is also here

Article Ways to resolve Selleri's paradox

which says a lot of interesting things, although it comes to the conclusion that SR should be able to give account to the effect...

straight from the fact that two counter-directed light beams have different path lengths in reaching the same moving target. It is a straightforward and elementary fact. If you deny such an evidence, I think there is little to discuss about.

In the case of the experiment of fiber optics, there is no centripetal acceleration at all where light is detected.

Stefano Quattrini "In the case of the experiment of fiber optics, there is no centripetal acceleration at all where light is detected."

The different centripetal accelerations are g1=(c²+v²)/R and g2=(c²-v²)/R.

This means the two light beams move in regions with a different gravitational field strength g1 and g2. Accordingly they experience different time dilations along their path.

Dear Stefano Quattrini

It is obvious that with that attitude a rational exchange is out of the question

So I will refrain from answering you anymore.

Justo Pastor Lambare ,

yes... it is obvious with yours

Wolfgang Konle б

Two objections.

1. It is too weak effect. In the optical fiber if the frequencies of the light beams change (due to rotation) the conditions for reflection of the beams change. In the other words, the decaying EM field penetrates into the reflecting cover to different depths. This depth depends on the frequency of the incoming and outcoming (of the 'reflecting surface') light beams.

So the optical paths of the beams can change (displace in radial direction).

This effect should be compared with the effect caused by the difference in centripetial accelerations.

2. In the experiments described in 'Modified Sagnac experiment for measuring travel-time difference between counter-propagating light beams in a uniformly moving fiber' the centrifugal acceleration is absent or too small because most of the paths is straight.

Dear all,

besides the fact that the interpretation of LT by Einstein and Lorentz are fundamentally different,

there is an important remark:

Einstein derived the following

t'= γ(t-vx/​c2 )

while Lorentz the following

t'=γ-1t- vx'/​c2

to pass from Einstein's to Lorentz'

γ(t-vx/c2) =γ(t(1-v2/c2+v2/c2)-vx/c2) =γ(t(γ-2+v2/c2)-vx/c2)= t (γ-1+γ v2/c2) - γ v x/c2

= γ-1 t - vγ (x-vt)/c2 = γ-1 t - v x'/c2

One has to accept in Einstein's version that the speed of light is exactly equal to the speed of signals used for synchronization.

if c at the denominator of the term vx'/​c2 derived as the synchronization speed in both versions, goes to infinite, Lorentz version provides a meaningful solution

t'=γ-1t

Einstein's instead goes into

t'=γ t

which is totally different and a meaningless result.

Let A and B denote the front and back of a train of length AB = d, in the rest frame K of the train. According to a frame K′ in which the train is moving at a uniform velocity v, the length is d′= d/γ(v). For an observer in K¢light emitted at B and received at A after Δt′ seconds has travelled the distance d′ plus an additional distance vΔt’ because, obviously, A continues to move while the light is travelling. Similarly, light emitted from A and received at B will take a shorter time because it’s travelled a shorter distance.

That is the linear Sagnac effect. It’s no mystery. It already appears in the final paragraph of section 2 in Einsteins 1905 publication!

The often discussed and unnecessarily controversial Sagnac effect due to rotation is explicable similarly. When the setup containing the emitter and receiver are rotating, say, countercockwise it is readily apparent from the viewpoint of an inertial observer, that the light travelling clockwise travels a greater distance than the light travelling clockwisw. Both travel at the same speed c. To a non-inertial observer rotating with the apparatus it would “seem as if” they travel the same distance.

Eric Lord

There are two differnt ways to analize and understand the Sagnac effect and both produce the same eresult. You can analyze it classically or you can use relativity.

Unfortunatelly the correct relativistic analysis is a little bit complicated because it involves non inertial systems.

Dear Eric

Eric Lord ,

I am quite confident of that in fact.

Einstein's train where light beams depart "at once" from the embankment and arrive non simultaneously to the half-way placed moving absorber , is exactly the same problem. That is true, provided that the rest frame of the linear problem matches with rest frame of the axis of rotation of the disk.

Both problems simply reduce to a "chasing down problem" in the stationary frame : Achille (light) and the turtle (interferometer).

A source of light shoots (Achille departs) when at distance H from the moving interferometer (turtles). Light, by chasing the interferometer takes more time or less time than H/c (if source and interferometer were at rest).

The time calculated in that case is H/c*1/((1-v/c)) which considering the differnence with H/c it becomes vH/c2/(1-v/c) hence vH/c2 which is the first order effect found in the experiments.

To take care of the higher orders approximations, it is necessary to consider the difference in the arrival times of the counter-propagating beams 2*gamma2 vH/c2 and the twin effect in the frame of the interferometer. It comes out the famous term of the Lorentz Transformations : gamma *vH/c2 which corresponds to a light-time variation in regards to the light-time at rest .

For the moving interferometer/turtle, light emitted at once did not reach it at once. That will always be the case since light propagates always in the same frame in any given physical problem.

For the interferometer this will occur as well if it is enclosed inside a box (moving frame) with light departing from the sides of the box, at once, if the synchronization stays the same as Sagnac's (ABSOLUTE).

For sure, if you Einstein-synchronize the clocks at the sides of the moving box and emit the light beams accordingly, the absorber will detect them simultaneously in the middle.

In such case you just "tricked" the system using an arbitrary synchronization in the moving frame, which keeps artificially the SOL invariant. That is unnecessary unless one wants to force the equivalence of frames (which is not in the facts) then the "weird" comes out . It is just a way to hide the presence of a frame of propagation which was strongly supported by Lorentz and Poincarè et many others.

Last but not least, the SOL invariance in every inertial frame deprives Physics of a precious degree of freedom...

To my understanding, other guys criticizing SR, assume that the light path of the photon is the same L

Article The Sagnac effect and the role of simultaneity in relativity theory

this does not fit either...

Justo Pastor Lambare ,

for what reason it should involve non-inertial systems?... Sagnac effect, as shown clearly, is irrespective of the inertiality of the systems and does not really care about centripetal accelerations. So calculations based on non inertiality are simply unnecessary or not right.

Eric Lord "For an observer in K¢light emitted at B and received at A after Δt′ seconds has travelled the distance d′ plus an additional distance vΔt’ because, obviously, A continues to move while the light is travelling. Similarly, light emitted from A and received at B will take a shorter time because it’s travelled a shorter distance."

Sorry, but this approach disregards the length dilatation, which then egalises the travel distances.

Wolfgang Konle ,

length contraction is a second-order effect in v2/c2, Sagnac effect is a first order in v/c, there will never be a compensation, maybe at relativistic speeds but it is never the case in Sagnac effect so far analyzed.

Travel distances will never be equal, never!! They can be measured equal only if Einstein synchronization is applied in the moving system as internal synchronization, then you can have the illusion that the light path connecting two objects is always the same.

Stefano Quattrini " ..Sagnac effect is a first order in v/c.."

What relates Erics example to the Sagnac effect?

Wolfgang Konle ,

Eric Lord provided a quite effective description about what is at the base of the Sagnac effect.

If one consider a disk with emitter and interferometer set at the opposite sides of a disk north-south, the Sagnac effect will be detected by the moving interferometer.

The detected phase variation would be half since the beams crossed only half of the circumference of the disk to reach the detector.

By considering yet another configuration

• emitter separated in two emitters set at opposite side, east-west,
• a signal departs from the center and triggers the light beams in the circumference to reach the absorber and the interferometer to move at speed v.
• The Sagnac effect would be detected as well, the phase detected will be half of the previous, always a function of the length of the light path.

by deforming the half circumference in a rectangle with long side 2R and short side R and synchronizing as before the light beam and the departure of the interferometer at speed v, the same result will be found according to the 2R lenght of the light path at rest.

Stefano Quattrini "Eric Lord provided a quite effective description about what is at the base of the Sagnac effect."

Yes I do not doubt, what Eric Lord provided. But just the example with two inertial reference systems is not necessarily related to the Sagnac effect.

Wolfgang Konle ,

the example with inertial systems, which also Eric Lord referred to, is represented in Einstein's train-embankment thought experiment.

A stationary body A on the embankment , placed in the middle of two sources set at distance H, is reached simultaneously by light beams. The travelling B at speed v, overlapping with A when light is emitted, does not detect the beams simultaneously.

B detects a non simultaneity of vH/c2 , that is half of the Sagnac effect if light crossed the length H (light path at rest was H/2 in this case).

To be more accurate A would detect offset: gamma2 vH/c2 while B detects offset: gamma vH/c2 (low speeds is just vH/c2 ).

The light paths for the stationary observer are both H/2, hence the light time H/2c.

The light paths measured by the moving observer are H/2 + H/2*v/c or H/2 - H/2* v/c, the light-time H/2c + vH/2c2 or H/2c - vH/2c2

Let's make a premise now, based on experiments:

Between two objects C and D by measured the two-way light path (RADAR) the time to connect D to D (passing from C) or C to C is 2*H/c, where H is measured with a meter stick. That implies that SOL two-way = c.

The above is the base of the Lorentzian interpretation of LT: the embankment is the preferred frame in the train-embankment experiment.

-------

Einstein made the following additional choice:

in any inertial frame the light time to connect C to D must be the light time to connect D to C, light_time(C,D)=light_time(C',D') = H/c. This is a consequence of the equivalence of the inertial frames...

That translates in the requirement that SOL one-way = c.

That can be seen as a direct consequence of Einstein's "synchronization procedure" : if two clocks in a inertial frame are Einstein synchronized the light time to connect them is always H/c.

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

In both cases the offset vH/c2 is detected, but it is very different the interpretation of it.

For Lorentz, the offset is just a variation of the light-path, hence the light time due to the motion of the observer differs by that quantity.

Lorentz does not require at all that, in the train, the SOL one-way = c (that is not the propagation frame of light , preferred frame by light), but only on embankment that requirement exists (same a Maxwell and Poincarè).

For Einstein, who imposes the equivalence of inertial frames hence the light time to be H/c , the offset must be an offset of the two clocks in the train frame , meaning that A and B in the train frame are actually desynchronized by the quanitity vH/c2

Einstein assumes that his synchronization procedure, since it is an experience performed in an inertial frame, has to provide same results in every inertial frames (complying with the equivalence of frames). To a certain extent it does and apparently it does its job also in non-inertial frames.

TO BE CONTINUED

Stefano Quattrini

In what inertial reference system do you consider the signal reception time?

Is it the time frame of body A at rest or the time frame of moving body B?

Considered in the time frame A you are correct. The reception time of both signals at location B there are different. But considered in the frame of the moving body B the reception times of both signals from left and from right are identical!

Wolfgang Konle ,

I made my last post much longer in the last few minutes, you may find the answer there..

Dear Vladimir Onoochin ,

As previously mentioned

Einstein derived the following LT-E (SR)

t'= γ(t-vx/​c2 )

while Lorentz the following LT-L (LET)

t'=γ-1t- vx'/​c2

with x' = γ(x-vt )

they both reduce to t'=t for c->oo, no doubt.

To pass from Einstein's to Lorentz' some algebraic passages are needed

γ(t-vx/c2) = γ(t(1-v2/c2+v2/c2)-vx/c2) = γ(t(γ-2+v2/c2)-vx/c2)= t (γ-1+γ v2/c2) - γ v x/c2 = γ-1 t - vγ (x-vt)/c2 = γ-1 t - v x'/c2

One has to accept in Einstein's version that the speed of light is exactly equal to the speed of signals used for Einstein's synchronization, that is peculiar of SR.

if c at the denominator of the term vx'/​c2 and vx/c2 coming out as a consequence of the synchronization speed in LT-E and the light time variation in LT-L, goes to infinite, Lorentz version provides a meaningful solution

t'=γ-1t

that is in fact possible in central synchronization for example, or external synchronization, (that is another way to implement the infinite synch speed)

Einstein's instead goes into

t'=γ t

which is a totally different and contrary to experiments.

Furthermore the interpretation of the term vx/c2 in LT-E is a desynchronization of clocks in the new frame with two clocks at speed v after being in synch in the stationary frame.

it is quite peculiar that the first approximation of LT-E does not work.

In the following paper LT are applied, the teacher is clever but not so clever as he expects from his students... He does not arrive to understand that what he found is quite important and disconfirms the base on which his interpretation (SR) of LT relies.

Article A twin paradox for 'clever' students

a) the twin effect result if calculated using the first order approximation of LT gives 2 Lv/c2 (low speed gamma->1) as the time difference between the stationary and moving clock when they rejoin.

b) the twin effect result, if calculated using the LT or TT (exact), gives vL/c2 as a first order approximation, as the time difference between the stationary and moving clock.

since (b) is the relation found valid in experiments, the relation in (a) is a non valid prediction. An invalid Physical prediction invalidates the relations where it comes from.

The LT approximation at first order t'=t-vx/c2 which provides such a value which is interpreted as a desync of clocks does not represent a physically meaningful relation, it is invalidated..

hence the use of LT with SOL one way c gives wrong results!!!!!!!!

Stefano Quattrini "The travelling B at speed v, overlapping with A when light is emitted, does not detect the beams simultaneously."

Sorry, but just this claim is wrong.

Wolfgang Konle ,

read the Einstein's train and embankment thought experiment.

A and B are the receivers. A is in the middle. After emission of the light beam and prior absorption by B, B has moved by a tiny fraction of H, which is H*v/c.

Stefano Quattrini

The receiver B moving with velocity v in respect to an emitter at rest receives a signal from the emitter exactly at the same time, regardless of its speed. The signal velocity is always c regardless of the velocity v of the receiver. The only thing which varies with v is the Doppler frequency.

Dear Stefano Quattrini,

I fully agree with you. But unfortunately you will not convince the mainstream physicists. Why do I think so? They will ask what experiment can give unambiguous and definite answer that you are right?

All reliable experiments that made to convince that the SRT is the true theory were made for the experiment setup moving uniformly with respect to some frame (microwave background radiation frame, for example). But all these experiments except the experiments with the meson decay can be explained by means of Lorentz's theory of absolute ether.

I attach Table 15-2 of Panofsky-Phillips textbook where the authors present a list what experiments cannot be explained by Lorentz.

Regarding the experiment with the meson decay, these particles are not stable. It means that we don't know their internal structure. How a meson structure changes at high velocities, we don't know. For example, Jefimenko gave alternative explanation of the results of these experiments.

On the mass-energy equivalence - until now the 4/3 problem has no solution.

On Kennedy-Thorndike experiments, I will email you simple explanation - based on the convection potential of the crystalline lattice - why and how the contraction of the moving bodies occurs.

Regarding the experiments with transverse Doppler shift, there is good experimental work of Hartwig Thim, which SRT followers try to ignore.

I write so long explanation with the only aim - in all these experiments, except the meson decay, time is not essential. It is quite impossible to make the experiment where the passage of time can be directly detected. But to show that you are right, such an experiment is needed. So the SRT followers can always appeal to the absence of such an experiments. Moreover, they can appeal to the Ives–Stilwell type experiments by ignoring Hartwig Thim's results.

Wolfgang Konle ,

Stefano Quattrini "B and A do not occupy the same position at the arrival of the light in A or B"

Yes, but this is irrelevant. When the light arrives at B, viewed by B, the distance from B to the emitter is subject of length dilatation.

Considering two situations (left/right) within one view does not alter each individual view.

Relativistic velocity addition keeps its validity. This leads to c+v=c-v=c.

Wolfgang Konle ,

again!!! I told you already this thing which is necessary to understand:

length contraction is a second-order effect in v2/c2,

Sagnac effect is a first order in v/c, there will never be a compensation, maybe you can find it at relativistic speeds, never the case in Sagnac effect so far analyzed v/c

Wonfgang Konle

The speed remains invariand as it should (according to relativity). You should use the relativistic formula for the adition of velocities.

Stefano Quattrini Keyword: synchronisation

By looking for differences between signal arrival times you only consider the shift terms in the Lorentz transform. But the problem concerns coordinate intervals and not absolute coordinates. The time and length intervals related to both emitters and the receiver located at the moving position B are subject of the consideration. These intervals in space and time are subject of Lorentz transforms. But in this transforms only the Lorentz factor appears. This leads to the fact that the time intervals on both sides are transformed by the same factor.

Wolfgang Konle ,

maybe you should look at this... who applies correctly the Lorentz Transformations

Article The case of the identically accelerated twins

SR interpretation, which is Einstein's and Boughn's , is that the clocks of the twins J and D desynchronized in the new frame at speed v by the quantity vH/c2 (as a first order approximation) considering H=x0 the initial distance.

LET interpretation, which is Lorentz' and assumes that the departure frame is the light propagation frame or preferred. The light-time to connect J and D in the new frame is not anymore H/c as in the stationary frame but H/c-vH/c2 , hence vH/c2 is its variation.

Since what can be measured at a distance is just the light-time, LET interpretation is the only one which is based on actual facts and it is also supported by Sagnac effect which is an absolute effect.

Stefano Quattrini

Yes, "The case of the identically accelerated twins" sheds new light on the twin paradox. The fact that a spatial separation in an accelerated system has the same influence as a height difference in a gravitational system is remarkable and up to now, I did not take into account this possibility.

This fact resolves the twin paradox. It also dramatically increases the impact of accelerations on relativistic scenarios.

But it does not have any influence on the interpretation of situations with a constant relative speed.

Dear Stefano Quattrini ,

A content of this post has no direct connection with the Sagnac effect. But because before I uploaded some information on the experiments which say in favor of the SRT and which cannot be explained by Lorentz's theory of stationary ether, I think it would be useful to explain how the relativists treat all experimental results in favor of the SRT. What is written on the Kennedy-Thorndike experiment at Wikipedia:

Because ΔL=c(TL-TT), the following travel length differences are given (ΔLA being the initial travel length difference and vA the initial velocity of the apparatus, and ΔLB and vB after rotation or velocity change due to Earth's own rotation or its rotation around the Sun)

$$

\Delta L_{A}=\frac{2\left(L_{L}-L_{T}\right)}{\sqrt{1-v_{A}^{2}/c^{2}}},\qquad\Delta L_{B}=\frac{2\left(L_{L}-L_{T}\right)}{\sqrt{1-v_{B}^{2}/c^{2}}}.

$$

(latex symbols)

In order to obtain a negative result, we should have ΔLA−ΔLB=0. However, it can be seen that both formulas only cancel each other as long as the velocities are the same (vA=vB). But if the velocities are different, then ΔLA and ΔLB are no longer equal. (The Michelson–Morley experiment isn't affected by velocity changes since the difference between LL and LT is zero.

https://en.wikipedia.org/wiki/Kennedy%E2%80%93Thorndike_experiment

But two points are ignored in such a treatment of the experimental results.

1. In order to use identical lengths of the arms of the Michelson interferometer, the experimentators had to control these lengths with accuracy to some micrometers (of the order of the wavelengh of the light beams in the interferomenter). It is very hard to provide such an accuracy for the lengths of the light beam paths under conditions of XIX century. If such lengths are checked with accuracy to 1 millimeter or even 0.1 millimeter, it is the same of interference of the light beams in a case when the lenghts are different. So both MM and KT experiments give the same results.

2. Persons, who state that they are able to put the experimental setup into the frame where the velocity of the apparatus = 0 with respect to the ether, don't understand that it is impossible. KT make the apparatus which moves with the Earth with the velocity U ~ 30,000 m/sec. There is no other velocity. They are only able to change orientation of the apparatus (to change the direction of the vector U) but gives nothing. vA = vB always.

Yes, it is possible to fix all parameters of the light beam and wait when the Earth moves in its orbit around the Sun and the velocity U changes. But in this case the experimentators had to measure the displacement of the interference pattern during this period.

So the optimistic statement that:

so it is also capable of measuring the dependence of the speed of light on the velocity of the apparatus.

is correct if the experimentators could change this velocity of the apparatus.

I suppose such a treatment of the experimentl results is being made for the Sagnac effect measurements.

Wolfgang Konle ,

has little to do with it actually...

what happens is just the change to speed v, at the end of the day what is relevant is what happens if the clocks pass from one frame to another.

if you read it well the result is exactly relevant to the relative speed.

Dear Vladimir Onoochin ,

thanks for your post which I will read.

I think MM and KT experiments null result have nothing to do with length contraction and time dilation. Unfortunately Lorentz was not right in assuming such features to justify the fact that no motion through "aether" can be detected. We cannot detect the motion of earth around SUN because the ECIF is a preferred frame and light there is isotropic full stop, a propagation frame.

It is inteteresting what is written in this paper

https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.509.6294&rep=rep1&type=pdf

which by the way is not well written to my opinion. Thanks to that It came to my mind a crucial idea which is hinted in that paper: light propagation domains.

Unfortunately Lorentz , Hertz and Poincarè, with the obsession of an "aether" as a special medium, did not focus on this possibilty..

For 50 years scientists lost their time on the *dragging* and *not dragging* issue, since Stokes. Why should Those properties be applicable ?

And then came Einstein who punished such a behaviour.. His oversimplification to the issue was quite welcome at that time since solved a lot of "problems" but with the Lorentz Transformaitons....

Dear Eric, Eric Lord ,

to my understanding

a) SR, due to the isotropy of light in all inertial frames says that: If the light time in one frame to connect A and B set at a fix distance H, measured by a meter stick, is H/c. it is the same if A and B are in any other frame at speed v.

b) Sagnac effect (also) in longitudinal motion shows that if the light time to connect A to B in the LAB is H/c, the light time to connect A to B in a longitudinally moving frame in the lab is H/c-vHc2 .

I do not think the two sentences can be reconciled..

I understand that with Einstein sync you get always (a). That is because Eisntein's sync assumes the isotropy of SOL and then clocks are adjusted accordingly.

Dear all,

So far there are two smoking guns pro the Lorentz Electrodynamics against (where the explanation of effects are not paradoxical) the isotropy of SOL in every IRF, supported by SR.

a) The linear Sagnac effect shows that the light time to connect the extremes of a meter stick in the LAB is not the same as the light time to connect the extremes of a meter stick moving within the LAB: v/c2 is the difference of the light times considering H=1, as a first order approx (it comes from the term vx/c2).

For sure if you Einstein synchronize them when at speed v in the LAB, you get always the same light time for any pair of clocks travelling at constant speed. That is obvious but you have just desychronized them in comparison to a region where the isotropy is fulfilled (THE LAB).

b) The space-like effect on time in the twin paradox, embodied by the term vx/c2 in LT (according to SR). If that is used alone, to give account to the results of the twin effect, clashes with the actual results experimentally verified.

https://www.researchgate.net/post/Twin_effect_out_of_relativity_of_simultaneity_is_it_possible

Ghosal , Nepal and Debarchana , relativists, wanted to demonstrate that the relativity of simultaneity is a phenomenon with an actual physical outcome, able to provide the "twin effect" as well, which is an absolute effect.

They started from t'= t-vx/c2 (First order approx of LT)

they obtained 2vL/c2, as the final result for the offset between the clocks of the twins.

That is at total variance with the value vL/c2 predicted as the first-order approximation of the effect and experimentally tested. Those values which should express the same thing are not reconcilable, meaning that what these authors found doesn't correspond to anything in physics. So what they found is a wrong prediction, although correctly derived.

They did not realize that their conclusions cut the legs of the chair where they were sitting. Worse comes to worse, they considered smart only the students who understood that ROS (first order effect) is actually part of the twin effect.

Basically what emerges from the two points illustrated is that the vx'/c2 in the time transformation of LT does not have anything to do with the timestamps of clocks, at variance with

t'=gamma-1t.

vx'/c2 is just a light time variation due the change of speed in the LAB which can be measured with the help of suitably synchronized clocks.

Stefano Quattrini "b) Sagnac effect (also) in longitudinal motion shows..."

Let us focus on the Lorentz transform of intervals. There is no coordinate shift term and no synchronisation issue. Ergo, there is no Sagnac effect of longitudinal motion. We only have t'=gamma-1t.

Wolfgang Konle ,

to your understanding, what do you think that this guy did?

Article The case of the identically accelerated twins

are you inventing something else?

SR interpretation, which is Einstein's and Boughn's , is that the clocks of the twins J and D desynchronized in the new frame at speed v by the quantity vH/c2 (as a first order approximation) considering H=x0 the initial distance.

LET interpretation, which is Lorentz' and assumes that the departure frame is the light propagation frame or preferred. The light-time to connect J and D in the new frame is not anymore H/c as in the stationary frame but H/c-vH/c2 , hence vH/c2 is its variation.

Stefano Quattrini

Don't mix an acceleration scenario like the twin paradoxon scenario with a static scenario like the alleged Sagnac effect of longitudinal motion.

In the twin paradoxon scenario, the time shift effect is essential. Just the spatial separation along an accelaration leads to the shift of the time between both twins. But in the case of longitudinal motion, there is no acceleration and considering intervals removes all shift terms. The remaining dilatation term does not lead to a Sagnac effect.

I stay to my claim that the Sagnac effect is restricted to acceleration scenarios and does not occur in situations with a constant relative velocity.

Wolfgang Konle ,

if your decision is to go against the experimental evidence, it is up to you.

For me Sagnac effect has nothing to do with acceleration, and the FO experiments shows that. if for you it is not like that, it is not my business and It is not the case for me to continue to talk about it since for me what you are proposing is just a physical absurdity.

Stefano Quattrini

We have the following facts:

If we consider intervals in situations of constant relative motion, the shift terms cancel out. Concerning intervals we only have dilatations in the Lorentz transformation.

In acceleration situations, the shift terms do not vanish.

Would you admit to those facts? About the consequences we then can discuss later.

Wolfgang Konle

You are right regarding the pure Sagnac effect, but Wang et al. figure out more general experiments where you have motions that include sections with uniform motion.

Of course, all the results are correctly accounted for by relativity theory, see for instance:

DOI: 10.1103/PhysRevA.94.063837

Stefano Quattrini 's argument:

"SR interpretation, which is Einstein's and Boughn's , is that the clocks of the twins J and D desynchronized in the new frame at speed v by the quantity vH/c2 (as a first order approximation) considering H=x0 the initial distance"

is very confusing. He believes that SRT is wrong because in SRT you use an incorrect synchronization of clocks. However, the argument is inconsistent because SRT is based on the assumption that c is a universal constant.

You either accept it or reject it but you cannot prove it wrong as he believes without entering contradictory and incorrect arguments.

That is very frustrating and instead of being a scientific discussion, it becomes a futile discussion between a religious fanatic trying to prove the existence of God to an atheist.

You cannot prove it, you either believe in God (absolute frame) or you deny it (SRT).

In science, in particular physics, you cannot prove that light speed is constant. What makes it different from religion? That you must falsify your belief until empirical evidence points to the contrary.

That is what happened, for instance, with the ether hypothesis,

physicists stopped believing it because the belief was falsified. On the other hand, so far no empirical convincing evidence contradicts the universal character of the speed of light.

Justo Pastor Lambare ,

Stefano Quattrini

If this is true and can be proven rigorously is surely huge news.

You can give some credibility to your spectacular assertion that SRT has been proven empirically incorrect by publishing a paper explaining it.

Or you can just write a comment explaining the errors in this paper:

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.94.063837#:~:text=https%3A//doi.org/10.1103/PhysRevA.94.063837

Let me guess. The establishment will not allow to tell the world that SRT is all wrong. Any resemblance with flat earthers' argument is purely coincidental.

Justo Pastor Lambare ,

where is it applied explicitly in that paper the fact that the light is isotropic in the moving frames?

The Lorentz transformation with light are certainly applied.. if you can find where it is clear that the 1-w-SOL is applied in moving frames it would be great.

In order to reply to your paper there is one which explains a lot of things and it is really well written

https://arxiv.org/pdf/2106.09537.pdf

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

https://ieeexplore.ieee.org/abstract/document/10192556

Dear all,

about Einstein LT and Lorentz LT

Preprint Einstein train-embankment thought experiment revisited

https://www.cell.com/heliyon/fulltext/S2405-8440(23)06798-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2405844023067981%3Fshowall%3Dtrue

The biggest problem of theoretical physics is that Einstein's relativity is considered holy and sacred since it venerates the light.

Here is the strongest disproof of Einstein's relativity, read it objectively :

https://www.researchgate.net/publication/347203242_The_correct_formulas_of_Michelson-Morley_experiment

Furthermore, Einstein's theories can't stand against Ockham Razor. Here is my Physics letter that disproves all Einstein's principles.

Read it please objectively by following Ockham Razor :

https://www.researchgate.net/publication/369143082_Physics_letter_Cosmical_observations_and_experiments_against_the_relativistic_explanations_of_the_Doppler_effect_and_the_Gravitational_effect_of_the_light

Dear all,

Preprint Einstein train-embankment thought experiment revisited

Let' suppose that two clocks A and B on the surface of earth at distant H along the equator have been Einstein synchronized.

If A sends its timestamp to B, B will detect the beam when tB=t'A so that B can claim to be synchronized with A ...

(Einstein synchronization considers the light time to connect two points H/c irrespective of the frame of reference)

Consider v as the tangential speed of A and B in the ECI frame

To make A and B really synchronous in the GPS, it is applied the Sagnac correction, since the light time to connect A to B is not H/c but H/c-vH/c2 (or

H/c + vH/c2 depending on the direction of the beam).

Once the Sagnac correction the observer using the clocks will detect that the speed of light between A and B is not anymore isotropic.

That happens if he continues to consider that the distance H is the space length crossed by light in joining A and B.

if the observer considers that the light-time to connect A to B: H/c-H*v/c2

and the relevant light path (space crossed by light) : H-H*v/c

then he can claim again that the SOL is c one-way, as in the ECI frame.

c=H/TE c= (H-H*v/c )/(H/c-H*v/c2 ) = (1-v/c )/(1/c-v/c2 ) =c

Let's consider Einstein's train embankment thought experiment E-TETE

FIRST PART

a) M is the mid point between emitters A and B, the stationary observer with the embankment.

b) M' is the mid point between emitters A' and B' , the relative moving observer stationary in the train.

c) Considering the constancy of SOL in the embankment and its independence of the speed of the emitter, property of waves (acoustics), it comes straightforward that M detects the incoming waves simultaneously while M' doesn't.

d) That non simultaneity detected by M' has nothing to do with what is called relativity of simultaneity, but it is the simplest implementation of Sagnac effect: if the midpoint M' moves at speed v during the emission, M' will detect the beams with a time offset (of at least) vH/c2 .

e) Basically Sagnac effect is the minimum offset between the detection of light waves, emitted at once and absorbed from opposite sides. Every other case where M' is not the midpoint, involves a larger offset.

f) So far *only* Lorentz Electrodynamics has been applied assuming that the Embankment is a preferred frame where light is isotropic, nothing else.

That is why E-TETE so far cannot say anything about relativity of simultaneity since the clause of independence of SOL for every observer has not been implemented at all.

SECOND PART

What is very often overlooked, are the light paths and the position of the points of emission of the light waves.

Now we let into the game Einstein's clause about the Invariance of SOL for every observer in this case the TRAIN.

g) To let the train to be an observer of the "same rank" as the embankment we Einstein synchronize the clocks of the emitters A' and B' in the train.

The observer of A' and B' measures the light time as H/c in the train.

h) What happens, as a matter of fact, for the observer in the embankment, is that the emission points A' and A are not anymore aligned in the same positions, as before, but misaligned of H*v/c.

The net result of Einstein synchronization procedure applied in the train is the misalignment of the actual position of emission points of embankment and rain. That space offset makes it seem to an observer in the train that those points are stationary with A' and B' (at least in the interval of emission absorption) not with A,B. Such misalignment is not "observer dependent" .

i) By assuming that light is isotropic in the Embankment frame it has been found a result which is inline with the experimental evidence of Sagnac effect which implies that the position of emission of the waves are stationary with the embankment.

l) By assuming that light is isotropic also in the IRF of the train, Einstein synchronized A' and B' will emit waves accordingly. The result is that M' will detect the beams simultaneously same as what happened when the clocks were set in sync within the embankment.

m) The observer co moving with the train, by assuming the isotropy of light in the train, will be confident that the position of emission of light in the train are stationary with A' and B'.

n) It is a fact that if a position is stationary in one frame, the same position cannot be stationary in another frame (having relative speed v).

CONCLUSION

(i) complies with experimental evidence assuming the positions stationary with the embankment,

(m) assumes as well isotropy of train's inertial frame, assuming as well that the positions are stationary with train's frame.

since (n) is true,

the clause (m) is singled out : the train frame is not equivalent to the embankment frame.

The position of emission of the waves are all stationary within the Embankment (to a very good approximation), never stationary with the train, although waves are emitted from the emitter comoving with the train at speed v.

If that wasn't the case, then the light path lengths would not be the same hence the SOL would not be invariant even in the embankment frame and the E-TETE would not provide the result according to Sagnac effect.

Einstein's synchronization makes it seem to the moving observer that everything happens as if his current frame is the preferred one, but as we have just seen it cannot be the case.

Stefano Quattrini "Let' suppose that two clocks A and B on the surface of earth at distant H along the equator have been Einstein synchronized."

In a rotating coordinate system Einstein synchronisation is not persistent.

Wolfgang Konle

You are right. Besides, if you assume that light speed is not constant and isotropic in every inertial frame, then you are already declaring that relativity is false; nothing else needs to be said.

So, all the stories that people advocating for the TT transformations tell about "Einstein synchronization" are just nonsense because:

1) They already rejected relativity when declaring light speed is not invariant.

2) Consequently nothing else needs to be said to "prove" relativity wrong, they disprove it by definition.

Furthermore, there is only one way to synchronize clocks, namely, by exchanging signals at constant speeds. Therefore, if light speed is not constant in a given frame, it does not make sense to synchronize clocks using light in that frame.

"Einstein synchronization" only in the isotropic frames.

In the other frames it desync the clocks

I completely agree: If use the formula t2=1/2(t1 + t'1 ) to synchronize clocks with a signal that has an anisotropic speed you are desynchronizing those clocks instead of synchronizing them.

Wolfgang Konle

in a rotating frame ESP fails...

if you continue to read I wrote

To make A and B really synchronous in the GPS, it is applied the Sagnac correction, since the light time to connect A to B is not H/c but H/c-vH/c2 (or

Justo Pastor Lambare ,

in Einstein's Train Embankment thought experiment I guess you agree that the 4 positions of emission of light are stationary with the embankment.

Stefano Quattrini

I guess it depends on how you want to interpret it.

According to what Einstein wanted to prove you have only two points at which the light beams are emitted. It is irrelevant whether they are on the train or in the embankment.

You have two possibilities 1) they are simultaneously emitted for the observer in the train, or 2) they are simultaneously emitted for the observer on the embankment.

You may choose either 1) or 2). The point is that if light speed is c for both, then if one of them sees the light beam emitted simultaneously, the other one does not.

It is quite simple indeed but people do not seem to understand that "you have to accept that c is the same for both"

Of course, you can reject that premise but if you want to understand Einstein's point you have to accept the premise at least momentarily.

The problem seems to be that usually, people have little training in logical thinking. It is a mere logical inference, P implies Q, P->Q.

As I said before, you can accept or reject the premise "P" but that has nothing to do with rules of inference.

From a purely logical stance, you can reject relativity by rejecting its premises. The problem is people want to find inconsistencies that do not exist.

The other point that I find is a problem, is that the "simultaneity of distant events" is taken as a single reality.

For relativity, there exists only one objective reality "the same place at the same time=spacetime event", so "two places at the same time" is not part of objective reality because there are two separate events in that happening.

Although relativity can be correctly rejected from a logical viewpoint, I did not yet see a logically correct argument against it.

Justo Pastor Lambare ,

don't be evasive. I am not talking about simultaneity now, which can be a consequence. But a very specific and physical matter IF some positions where emission occurred are stationary within the embankment cannot be stationary also in the train...

Stefano Quattrini

Then you did not understand a word of what I tried to explain. I guess is my fault. It is better to end it here. I am sorry.

Justo Pastor Lambare ,

the answer is simple and it does not depend on any particular theory, it only depends on the independence of SOL on the emitter.

The position of the emission points are fixed in the embankment otherwise the predicted effect which is the very gist of Sagnac effect would not occur.

This makes the Embankment the isotropic frame.

Since the positions in one frame cannot be fixed in a relative moving frame the answer is quite obvious...

If you conflate your personal interpretation with that of Einstein, then you will never understand what Einstein said in the first place.

According to Einstein, the embankment and the train frames are both isotopic.

Do you want to disscuss your interpretation or Einstein's?

If you want to be isotropic only the frame where the source is stationary, that is ok. Just accept that is how you want it to be and declare Einstein is wrong. Nothing else needs to be said.

One last thing, ETETE has nothing to do with the Sagnac effect. But maybe that is different according to your interpretation.

Justo Pastor Lambare ,

this is clear...

a source of light can be stationary in any frame.

it is the position of the point of emission which makes the difference

I think you have some difficulties in really understanding these things.

Ask Eric Lord about it...or Kassner

Both Sagnac and E-TETE rely on a specific fact:

the detection by a moving observers, of waves emitted simultaneously from opposite directions, nothing more.

The fact that the object moves in the interval between emission and detection makes the effect. That simply makes the light paths to reach the moving objects of different lengths.

in Sagnac effect, the circuit is a closed circuit, no need of synchronization.

In E-TETE the setup is longitudinal and a synchronization is needed. As a matter of fact the E-TETE is the rectilinear version of the Sagnac effect.

Also in E-TETE Synchronization can be automatic without clocks, if the emissions from the sides of the wagon and the embankment are both triggered by an event of overlapping of twin structures one stationary on the embankment the other stationary with the train.

Preprint Einstein train-embankment thought experiment revisited

Stefano

Let me put it this way:

There is nothing very interesting to be discussed regarding the ETETE.

It is a mere very trivial inference that can be explained like this,

1) If you assume light speed invariance, then absolute simultaneity must be forsaken.

2) If you want to keep absolute simultaneity, then light speed cannot be invariant.

An example of 1) is SRT, while an example of 2) is TT.

There is nothing more to it.

Justo Pastor Lambare ,

I repeat, the working principle is the same as Sagnac effect, a light path difference involves a non simultaneity : vH/c2 is just the difference of the times of arrival of light, considering that H/c is the time of arrival for a stationary absorber.

Yes if one assumes light speed Invariance also in the train, or light speed invariance also for the the observer co-moving interferometer for Sagnac

Yes, sure the preferred frame can be only one which is the embankment

there is a lot more than that and the discrimination is given by the positions of the points of emission of light.

They are stationary with the embankment in order to provide the phenomenology it provides of simultaneity of M and non simultaneity of M'.

The are not stationary with the train.

The only way to make them stationary with the train is to force the SOL to be invariant, but since if they are stationary with the train they cannot be stationary also with the embankment the SOL cannot be an invariant.

Stefano Quattrini

I guess the relevance of ETETE is subject to personal opinion.

In my opinion, it makes an important conceptual point but since it is very easy to understand to the point that anyone with no knowledge of physics can understand it, I consider it rather trivial.

The proof of my previous assertion is that Einstein used it even in popular books addressed to the general public.

On the other hand, the Sagnac effect is not that trivial. It cannot be understood properly unless you know some physics.

The proof that it is not trivial is testified by myriads of incorrect explanations even in published papers claiming either to prove or disprove relativity.

I know only two papers that explain correctly why it is not a disproof of relativity:

1) Response to ‘‘Comments regarding recent articles on relativistically

rotating frames’’ (Am J. Phys. 67 (2), 158 (1999)) by T. A. Weber

Article Response to “Comments regarding recent articles on relativis...

2)Special theory of relativity and the Sagnac effect by A. A. Logunov and Yu. V. Chugreev

Article METHODOLOGICAL NOTES: Special theory of relativity and the S...

The first paper contains only a very short but correct explanation regarding the physics of rotating systems.

The second one is more detailed and addresses the Sagnac effect directly.

PS: There are indeed many papers explaining the Sagnac effect using relativity but few that give correct counterarguments to the claim that it disproves relativity.

Justo Pastor Lambare ,

I agree that what happens in E-TETE it is quite easy to understand but the very basic working principle is the same as Sagnac which, as a close circuit, is much less easier to understand..

The other point is that E-TETE in the trivial form presented by Einstein does not demonstrate anything about relativity of simultaneity, at variance to what one would expect also because it is all based on the isotropy of light in the Embankment frame which is also what LE supports.

If one wants to show something about the consequences of the constancy of SOL for every observer the setup has to be enriched a lot and it gets much more complicated.

Sagnac effect , less intuitive than E-TETE gave also further issues

a) since 1916 there was a dispute if it was or not appropriate to explain it with SR (Einstein himself considered necessary GR) since it involves rotation.

b) it was conceived by Sagnac to show a preferred frame, so a disproof of the equivalence of frames... nevertheless the frames were not inertial...

c) a very direct way to find that effect, at least at the first order, occurs just applying Classical physics.

d) explanations which involve SR are usually quite complicated

For how weird it may seem, E-TETE and Sagnac BOIL DOWN on yet another first principle which is also the root of the Lorentz Transformations and Lorentz Field Transformations:

the famous "chasing problem" of Achilles and the Turtle....

The time taken to reach a moving target, by a signal emitted while the target was at a fix distance x0 from the source.

Stefano Quattrini

Interesting points.

That dispute was long settled. Einstein even believed that the twin paradox can only be properly understood with GR. He was wrong; he understood that later. The reason is that GR is not "general relativity" but a gravitation theory. He realized that only later in his life and after other scientists criticized his initial interpretation of GR.

However, that confusion persists nowadays in some cases.

That is completely incorrect. The equivalence of frames has been the basis of all we know and understand about physics since the times of Galileo.

Sagnac wanted to prove the existence of the luminiferous ether as well as Lorentz and others who had problems with letting go of the ether.

The ether is related only to Maxwell's equations and frees those equations from the need to remain invariant under Galileo transformations.

That understanding is wholly different from the so-called "preferred frame" or absolute frame that ALT interpretation upholds.

The position of Lorentz and other ether theorists was physically consistent and coherent but has to be abandoned only on empirical bases.

Justo Pastor Lambare

correct, and that would wipe away the equivalence of frames, since aether is a preferred frame hence Galileo would be just a first order approximantion..