Did Lorentz or Einstein theoretically derive special relativity?

[zheng89120]

because it seems the Lorentz transformations constitute special relativity itself

 

[BruceW]

From what I heard, Einstein did not contribute much to the mathematics of special relativity, but it was him who made the big leap to use the maths to reformulate the laws of spacetime

 

[Dschumanji]

According to the book that Einstein wrote to explain the special and general theories of relativity to the layman:

But there are two classes of experimental facts hitherto obtained which can be represented in the Maxwell-Lorentz theory only by the introduction of an auxiliary hypothesis which in itself--i.e. without making use of the theory of relativity--appears extraneous.

It is known that cathode rays and the so called beta rays emitted by radioactive substances consist of negatively electrified particles (electrons) of very small inertia and large velocity. By examining the deflection of these rays under the influence of electric and magnetic fields, we can study the law of motion of these particles very exactly.

In the theoretical treatment of these electrons, we are faced with the difficulty that electrodynamic theory of itself is unable to give an account of their nature. For since electrical masses of one sign repel each other, the negative electrical masses constituting the electron would necessarily be scattered under the influence of their mutual repulsions, unless there are forces of another kind operating between them, the nature of which has hitherto remained obscure to us. If we now assume that the relative distances between the electrical masses constituting the electron remain unchanged during the motion of the electron (rigid connection in the sense of classical mechanics), we arrive at a law of motion of the electron which does not agree with expereience. Guided by purely formal points of view, H.A. Lorentz was the first to introduce the hypothesis that the form of the electron experiences a contraction in the direction of motion in consequence of that motion, the contracted length being proportion to the expression\frac{1}{\gamma}This hypothesis, which is not justifiable by any electrodynamical facts, supplies us then with that particular law of motion which has been confirmed with great precision in recent years.

The theory of relativity leads to the same law of motion, without requiring any special hypothesis whatsoever as to the structure and the behaviour of the electron.

...

[The following concerns the Michelson and Morley experiment]
Lorentz and Fitzgerald rescued the theory from this difficulty by assuming that the motion of the body relative to the aether produces a contraction of the body in the direction of motion, the amount of contraction being just sufficient to compensate for the difference in time mentioned above.

If I understand this correctly, it seems that Lorentz used his transformation to model the contraction of electrons as they moved at high speeds. He also used it to save the aether theory. Einstein's theory of special relativity applies to more than just electrons and rejects the idea of the aether. Lorentz was on the right track, he just didn't make that extra step that Einstein did.

 

[harrylin]

because it seems the Lorentz transformations constitute special relativity itself

According to Einstein's summary* in 1907, both of them did (Lorentz in 1904 and Einstein in 1905). He claimed not to have known Lorentz's 1904 paper (not to mention the one of Poincare!); but even if in fact he did know one or the other, his 1905 papers made important contributions to the development of the theory.

*http://www.soso.ch/wissen/hist/SRT/E-1907.pdf (sorry: in German)

 

[harrylin]

According to the book that Einstein wrote to explain the special and general theories of relativity to the layman:

If I understand this correctly, it seems that Lorentz used his transformation to model the contraction of electrons as they moved at high speeds. He also used it to save the aether theory. Einstein's theory of special relativity applies to more than just electrons and rejects the idea of the aether. Lorentz was on the right track, he just didn't make that extra step that Einstein did.

That only related to Lorentz's theory of electrons; the new theory (both Lorentz's and Einstein's accounts) applied to all matter and EM waves.

Note: I wonder why there is an issue about "who derived" SR, and not about "who derived" QM...

 

[PAllen]

That only related to Lorentz's theory of electrons; the new theory (both Lorentz's and Einstein's accounts) applied to all matter and EM waves.

Note: I wonder why there is an issue about "who derived" SR, and not about "who derived" QM...

Well, I see a combination of celebrity culture, media, and politics involved. Einstein got atypical acclaim, and was Jewish at a bad time. With QM, you got features named after people (Schrodinger wave equation, Heisenberg uncertainty principle, etc.). If the relativity theory as whole had a neutral name, in which there was the Lorentz transform, Einstein invariance principle, etc. vs. Einstein Theory of Relativity, there would presumably be much less obsession.

I guess also, though SR like QM was really developed by many people, Einstein's paper had an electric influence, more than any single QM paper. It was written for physicists, physically motivated, and collected everything into a coherent framework (whereas Poincare had tidbits in several papers, notes, and letters, often written more from the mathematical frame of mind).

 

[Zentrails]

because it seems the Lorentz transformations constitute special relativity itself

Einstein's miracle year paper on special relativity used simple geometry to establish the basic Special Relativity equations. He used the concept of an inertial frame of reference, but kept all the math within that frame, IIRC, negating the need for any mathematical transformations.

He did compare two different frames of reference and ask the thought question, what would be the geometry given the fact that observers in each frame measure the speed of light to be the same.

The math is actually quite simple. The old notion that "only a few people" understood Einstein's theory of Relativity certainly did not apply to Special Relativity, which Einstein admitted that shouldn't have included the word, "relativity."

Einstein was not a particularly good mathematician. Someone else had to point out to him that Rieman geometry would be apropos for his General Relativity theory.

He actually seemed to come up with his theories visually first, then looked for elegant mathematics to support it second.

 

[Dschumanji]

Einstein was not a particularly good mathematician. Someone else had to point out to him that Rieman geometry would be apropos for his General Relativity theory.

I've heard that this wasn't the case...

 

[GrayGhost]

According to the book that Einstein wrote to explain the special and general theories of relativity to the layman:

If I understand this correctly, it seems that Lorentz used his transformation to model the contraction of electrons as they moved at high speeds. He also used it to save the aether theory. Einstein's theory of special relativity applies to more than just electrons and rejects the idea of the aether. Lorentz was on the right track, he just didn't make that extra step that Einstein did.

Not exactly. Lorentz derived his transformations to force-fit the MMX null result. IOWs, to show the Fitzgerald contraction could be real. The assumption of an aether was prevalent then and Lorentz did assume it existed, so he built his model assuming such (apriori). Lorentz was on the right track only because he accepted that length contractions must exist. He was on the wrong track because he assumed all motion was relative to the aether frame. Yet amazingly enough, his transformations equations were correct, however they meant something different (from Einstein's).

Einstein assumed apriori that the 2 postulates were true. His LT derivation showed they were mathematically compatible, if true. It satisfied the MMX null result, w/o first assuming upfront that length contractions arose with relative motion. Einstein showed that the electron length-contracts "not because it shrinks in and of itself in an aether that never changes", but rather because the measure of space and time changes with a change in relative motion. So Einstein's LTs revealed a symmetry of space and time that is required assuming upfront that the 2 relativity postulates true, where no material body ever changes in and of itself no matter how it changes in its own state of motion.

GrayGhost

 

[JesseM]

Not exactly. Lorentz derived his transformations to force-fit the MMX null result.

Isn't length contraction alone enough to explain MMX, without time dilation or relativity of simultaneity? I thought Lorentz derived it as the transformation that would preserve Maxwell's laws of electromagnetism in different frames.

 

[GrayGhost]

Isn't length contraction alone enough to explain MMX, without time dilation or relativity of simultaneity?

Well, the assumption back then was isotropic light in only the aether frame. From the POV of an aether frame observer, I suppose one could show length contraction w/o time dilation. I don't see how one could do it from the Earth frame POV though, w/o invoking time dilation ... it seems to me that the explanation would have been incomplete.

I thought Lorentz derived it as the transformation that would preserve Maxwell's laws of electromagnetism in different frames.

Well, I'm sure that was the goal, yes. However, going in, said goal had to satisfy the Fitzgerald contraction predicted by the already verified MMX null result, while assuming a master aether frame. As you know, Einstein's approach satisfied the MMX null result w/o first assuming either a master aether frame or a Fitzgerald contraction.

GrayGhost

 

[harrylin]

Isn't length contraction alone enough to explain MMX, without time dilation or relativity of simultaneity? I thought Lorentz derived it as the transformation that would preserve Maxwell's laws of electromagnetism in different frames.

Yes indeed. Lorentz derived the equations (although not in the symmetrical form of Poincare as we know them today) in order to comply to the principle of relativity.

 

[JesseM]

Well, the assumption back then was isotropic light in only the aether frame. From the POV of an aether frame observer, I suppose one could show length contraction w/o time dilation. I don't see how one could do it from the Earth frame POV though, w/o invoking time dilation ... it seems to me that the explanation would have been incomplete.

Well, you could either just use the Galilei transformation for the Earth frame with the understanding that coordinate length was different than ruler length along the axis of motion relative to the aether, or you could come up with a new coordinate transformation such that coordinate length still matched ruler length in the Earth frame, if we say the aether frame is unprimed and the Earth frame is primed (and the aether is moving parallel to the x' axis of the Earth frame) it would just look like this:

x' = gamma*(x - vt)
y' = y
z' = z
t' = t

...then you could use this transformation to figure out how fast light moves in different directions in the Earth frame, given that it moves at c in all directions in the aether frame. Should then get the same prediction for the MMX in the Earth frame as you got in the aether frame, with no time dilation needed.

 

[ZealScience]

Lorentz transformation is actually from FitzGerald's answer to the Michelson-Morley experiment, and Lorentz summed them up. However Neither of them understand the meaning of the equations, it's Einstein who derived them and apply them to relativity which is not simply transformation. Even Lorentz himself praised that Einstein what hell of a genius!

 

[nitsuj]

because it seems the Lorentz transformations constitute special relativity itself

I think Einstien by leaps and bounds "theoretically derive[d] special relativity" before Lorentz (or anyone else for that matter). His intuition is remarkable even in the context of civilizations greatest scientists.

I forget where but I heard someone say "If I could ask Eistien one question it would be 'how did you know your thinking was on the right track?'"

So true, people everywhere think about this stuff and go off in some pretty fantastic directions, but Eistien was right. And pursued his intuition like he had read the theory from God's physics handbook.

Einstiens low profile may have helped keep him under the radar of other great minds of the time, so no direct competition. (I think with GR he did have some racing to beat him to the finish line, but from a mathimatical perspective)

A good story with a simular "who came up with it first?" Watson & Crick's pursuit of DNA (specificaly it's shape, solid proof), a very competitive race for sure.

 

[Zentrails]

I've heard that this wasn't the case...

I was speaking relatively. LOL

He was a far better mathematician than me or anyone I know, of course.
Just not as good as the top physics scientists he was competing with at the time.

 

[Zentrails]

I think Einstien by leaps and bounds "theoretically derive[d] special relativity" before Lorentz (or anyone else for that matter). His intuition is remarkable even in the context of civilizations greatest scientists.

I forget where but I heard someone say "If I could ask Eistien one question it would be 'how did you know your thinking was on the right track?'"

So true, people everywhere think about this stuff and go off in some pretty fantastic directions, but Eistien was right. And pursued his intuition like he had read the theory from God's physics handbook.

Einstiens low profile may have helped keep him under the radar of other great minds of the time, so no direct competition. (I think with GR he did have some racing to beat him to the finish line, but from a mathimatical perspective)

A good story with a simular "who came up with it first?" Watson & Crick's pursuit of DNA (specificaly it's shape, solid proof), a very competitive race for sure.

I agree and "track" is a good word to use, since there were trains and boats for mass transportation back then and that was it. So he visualized things mostly by thinking of trains, even more amazing when you think about it.

If I remember Watson's "Double Helix" book correctly, Watson & Crick were far ahead of their ONLY competitor (Linus Pauling) because Linus was convinced a triple helix was the correct structure. Watson's Cambridge group collaberated with Franklin's Kings college group, before which there were only 3 groups in the DNA "race."

Time sure have changed since then.

 

[homology]

I was speaking relatively. LOL

He was a far better mathematician than me or anyone I know, of course.
Just not as good as the top physics scientists he was competing with at the time.

We probably need to be careful to understand the times in which these folks worked. Things like group theory, operators, manifolds etc are common in physics now you'll see most of them at the undergrad level. But even the topic of matrices was not common among physicists at one time let alone functional analysis or differential geometry.

For example there's the following story about Gell-Mann (I'm just copying and pasting this from http://math.ucr.edu/home/baez/diary/march_2007.html" :

"Block is an expert on Lie algebras, and there's a fun story about him and Murray Gell-Mann, the physicists who one the Nobel prize for inventing "quarks". Actually quarks were part of a mathematical scheme which Gell-Mann called the Eightfold Way, because it was based on the 8-dimensional Lie algebra su(3).

The story goes like this:

Murray Gell-Mann's dream was to find a Lie algebra whose representations could model the observed baryons and mesons. A long time ago Heisenberg had invented a theory like this based on the Lie algebra su(2). This was able to account for baryons and mesons known at the time, but a lot more were discovered later. Gell-Mann knew this Lie algebra should contain the 3-dimensional Lie algebra su(2), since he wanted his theory to include Heisenberg's. In 1960 he worked on this problem for 6 months. He tried inventing 4-dimensional Lie algebras, then 5-dimensional ones, then 6-dimensional ones, then 7-dimensional ones... and gave up in disgust at this point, since nothing worked.

Then he talked to Richard Block, who is now a emeritus professor here at UCR, but was then an assistant professor at Caltech. Block told Gell-Mann that he'd been reinventing the wheel, and not doing a great job of it either: Élie Cartan had classified simple Lie algebras a long time ago, and after su(2) the smallest one is 8-dimensional, namely su(3).

Gell-Mann then invented the Eightfold Way.

I think that at the time, only 7 of the particles in the "meson octet" were known. The Eightfold Way said there should be 8, because su(3) is 8-dimensional. The missing meson — the eta — was discovered later"

 

[BruceW]

Love it when a plan comes together

 

[ZealScience]

I think Einstien by leaps and bounds "theoretically derive[d] special relativity" before Lorentz (or anyone else for that matter). His intuition is remarkable even in the context of civilizations greatest scientists.

I forget where but I heard someone say "If I could ask Eistien one question it would be 'how did you know your thinking was on the right track?'"

So true, people everywhere think about this stuff and go off in some pretty fantastic directions, but Eistien was right. And pursued his intuition like he had read the theory from God's physics handbook.

Einstiens low profile may have helped keep him under the radar of other great minds of the time, so no direct competition. (I think with GR he did have some racing to beat him to the finish line, but from a mathimatical perspective)

A good story with a simular "who came up with it first?" Watson & Crick's pursuit of DNA (specificaly it's shape, solid proof), a very competitive race for sure.

I don't quite agree with the fact, because lorentz transformation is from late 19th century (when Einstein was just a teenager), inspired by the famous michelson morley experiment, but paper on relativity starts around 1905. But lorentz himself didn't understand the lorentz transformation well, relativity to some extent explain the physics behind. So the famous Lorentz transformation should also be credited to Lorentz.

But Watson & Crick pursuit of DNA also is sort of contraversial considering the contribution from Franklin (a female biologist, Ican't remember the full name)

Another example, should be Mr Pauli, he seems to "borrowed" some ideas from others, but still he is known as a great scientist who contributes toward the exclusion principle.

But Einstein is certainly the only person in interpretating relativity for sure.

 

[Zentrails]

But Watson & Crick pursuit of DNA also is sort of contraversial considering the contribution from Franklin (a female biologist, Ican't remember the full name)

It's Rosalind Franklin.

 

[GrayGhost]

Well, you could either just use the Galilei transformation for the Earth frame with the understanding that coordinate length was different than ruler length along the axis of motion relative to the aether, or you could come up with a new coordinate transformation such that coordinate length still matched ruler length in the Earth frame, if we say the aether frame is unprimed and the Earth frame is primed (and the aether is moving parallel to the x' axis of the Earth frame) it would just look like this:

x' = gamma*(x - vt)
y' = y
z' = z
t' = t

...then you could use this transformation to figure out how fast light moves in different directions in the Earth frame, given that it moves at c in all directions in the aether frame. Should then get the same prediction for the MMX in the Earth frame as you got in the aether frame, with no time dilation needed.

Maybe so, but one would have an incomplete and incorrect model of nature.

Lorentz and Einstein obtained the same LTs. One assumes an invariant c in only the master aether frame, and the other assumes invariant c in any and all inertial frames. Now, I'm not very familiar with the Lorentz derivation, but here's the thing ... Einstein generates his linear coefficients alpha(v) and phi(v). He deterimines by logical deduction that phi(v)=1, and thus that aplha(v) = 1/beta(v) ... beta(v) being known as gamma(v) today. IOWs, Einstein did no force-fitting of group symmetries to obtain his transforms.

If I may ask you ... did Lorentz force-fit his coefficients to obtain the group symmetry that he (and Poincare) knew was required to ensure the principle of relativity, or did they naturally evolve as in the case of OEMB?

GrayGhost

 

[harrylin]

Maybe so, but one would have an incomplete and incorrect model of nature.

Lorentz and Einstein obtained the same LTs. One assumes an invariant c in only the master aether frame, and the other assumes invariant c in any and all inertial frames. Now, I'm not very familiar with the Lorentz derivation, but here's the thing ... Einstein generates his linear coefficients alpha(v) and phi(v). He deterimines by logical deduction that phi(v)=1, and thus that aplha(v) = 1/beta(v) ... beta(v) being known as gamma(v) today. IOWs, Einstein did no force-fitting of group symmetries to obtain his transforms.

If I may ask you ... did Lorentz force-fit his coefficients to obtain the group symmetry that he (and Poincare) knew was required to ensure the principle of relativity, or did they naturally evolve as in the case of OEMB?

GrayGhost

What do you mean with "force-fit"? Lorentz found by logical deduction that only a coefficient l=1 leads to the correct equations, and concludes:

The value of the constant must be unity, because we know already that, for w=0, l=1.

We are therefore led to suppose that the influence of a translation on the dimensions (of the separate electrons and of a ponderable body as a whole) is confined to those that have the direction of the motion, these becoming k times smaller than they are in the state of rest.

http://en.wikisource.org/wiki/Electromagnetic_phenomena

It's perhaps useful to point out that in 1904 he thus derived the Lorentz contraction from the PoR.

 

[nitsuj]

If I remember Watson's "Double Helix" book correctly, Watson & Crick were far ahead of their ONLY competitor (Linus Pauling) because Linus was convinced a triple helix was the correct structure. Watson's Cambridge group collaberated with Franklin's Kings college group, before which there were only 3 groups in the DNA "race."

Time sure have changed since then.

As you said, that is Watson's book you read.

 

[GrayGhost]

What do you mean with "force-fit"? Lorentz found by logical deduction that only a coefficient l=1 leads to the correct equations...

Thanx Harrylin. By force-fit, I meant "not by logical deduction, but rather by insertion". IOWs, if you assume you know the required final form of the equations to guarantee the PoR, you "make it happen" during derivation. From what you say, Lorentz obtained his linear coefficients by deduction, as Einstein did. I'll have to read thru his paper more closely.

Wrt the PoR ... Consider a dual pan balance whereby the line joining the pan midpoints are aligned with the balance's propagational path. Assume the pans are separated by a very long beam, and the wonder beam cannot bend. Further assume that "someone who believes himself at rest in Lorentz's master aether frame" records the balance's motion at luminal v thru the aether. Now, LET and SR produce the very same solns, so in either case, observers at rest with the balance should always witness the same result(s) ... ie, it's presumedly not possible to distinguish between SR & LET by experiement. Now, let's say 2 weights of identical mass drop from the sky, always of identical velocity and strike the balance pads AT ONCE "per an observer at rest with the balance". What would each theory predict wrt the balance beam tilting upon impact?

SR says ... the balance beam would not tilt.

LET (I think) would say ... the balance beam tilts, because the 2 weights do NOT strike the pads AT ONCE per an aether frame observer "if they strike the pads AT ONCE per the observer moving with the balance thru the aether". The aether POV is always right.

Wrt LET theory ... How is it that the PoR is upheld by LET theory? It seems to me that ... even though the LT results are the same in either case, they do not mean the same thing. The PoR "only appears to be upheld" (per LET) from a kinematic standpoint, but not with regards to force, and thus not with regards to energy. What is wrong with my reasoning here?

It's perhaps useful to point out that in 1904 he thus derived the Lorentz contraction from the PoR.

If all the coefficients were logically obtained by deduction, then I would agree. However, it just seems to me that the PoR is upheld kinematically, but not beyond that. How do you explain the scenario I pose above?

GrayGhost

 

[harrylin]

Thanx Harrylin. By force-fit, I meant "not by logical deduction, but rather by insertion". IOWs, if you assume you know the required final form of the equations to guarantee the PoR, you "make it happen" during derivation. From what you say, Lorentz obtained his linear coefficients by deduction, as Einstein did. I'll have to read thru his paper more closely.

How can one know what guarantees the PoR without first deriving it? Before 1904 Lorentz kept the unknown factor l in his discussions, leaving the question open if what we now call Lorentz contraction is indeed the right solution.

Wrt the PoR ... Consider a dual pan balance whereby the line joining the pan midpoints are aligned with the balance's propagational path. Assume the pans are separated by a very long beam, and the wonder beam cannot bend. Further assume that "someone who believes himself at rest in Lorentz's master aether frame" records the balance's motion at luminal v thru the aether. Now, LET and SR produce the very same solns, so in either case, observers at rest with the balance should always witness the same result(s) ... ie, it's presumedly not possible to distinguish between SR & LET by experiement. Now, let's say 2 weights of identical mass drop from the sky, always of identical velocity and strike the balance pads AT ONCE "per an observer at rest with the balance". What would each theory predict wrt the balance beam tilting upon impact?

SR says ... the balance beam would not tilt.

LET (I think) would say ... the balance beam tilts, because the 2 weights do NOT strike the pads AT ONCE per an aether frame observer "if they strike the pads AT ONCE per the observer moving with the balance thru the aether". The aether POV is always right.

Wrt LET theory ... How is it that the PoR is upheld by LET theory? It seems to me that ... even though the LT results are the same in either case, they do not mean the same thing. The PoR "only appears to be upheld" (per LET) from a kinematic standpoint, but not with regards to force, and thus not with regards to energy. What is wrong with my reasoning here?

If all the coefficients were logically obtained by deduction, then I would agree. However, it just seems to me that the PoR is upheld kinematically, but not beyond that. How do you explain the scenario I pose above?

GrayGhost

Probably you mean with "LET" Lorentz's 1904 paper, which Einstein summarized in 1907 together with his 1905 paper as the new theory that is based on the PoR (and which he later renamed "SR").
To be frank, I did not carefully read your example as any such discussion or paradox that I know of can be rephrased by replacing "aether" or "aether frame" by "rest frame". For a correct understanding of SR it is essential to realize that according to SR you may assume any inertial frame to be "truly in rest" so that the laws of nature should be valid wrt it, without any frame jumping.
Thus rephrased in interpretation-free SR:

"the 2 weights do NOT strike the pads AT ONCE per a rest frame observer if they strike the pads AT ONCE per the observer who is moving with the balance".

Note:a wonder beam that cannot bend cannot exist in SR

Harald

 

[Zentrails]

For a correct understanding of SR it is essential to realize that according to SR you may assume any inertial frame to be "truly in rest" so that the laws of nature should be valid wrt it, without any frame jumping.
Thus rephrased in interpretation-free SR:

"the 2 weights do NOT strike the pads AT ONCE per a rest frame observer if they strike the pads AT ONCE per the observer who is moving with the balance".

Note:a wonder beam that cannot bend cannot exist in SR

Harald

A non-accelerating frame of reference is all that is required for SR, which led Einstein to the next logical step and thought experiment - accelerating frames of reference and how the physics in them share many similarities with the physics inside a frame of reference fixed on the solid surface of a planet, or any non-solid surface where buoyancy is at equilibrium.

 

[GrayGhost]

harrylinn,

When one says "wonder beam", most folks generally accept that the beam does something that cannot happen in relality, or at least in practice to date. No different from discussing a wonder-traveler who attains c, which everyone knows cannot happen. But just for the sake of point, let's assume a wonder beam.

Well, I understand how SR handles my stated scenario. You skipped over that at first, and it remains clear that you are misreading it based on your prior response. I'm questioning the LET interpretation, that's all. As I said, I have not studied LET in any depth. If I may amplify my prior scenario a bit here ...

Assume a clock is attached to each always-inertial balance PAD, and they have been synchronized prior by the Einstein/Poincare synchronisation method.

SR says that the clocks are truly synchronised per those at rest with the balance, whereby the like-readouts are always simultaneous.

LET says that the clocks appear synchronised per those at rest with the balance, but are not truly simultaneous. An observer at rest in the aether frame disagrees that the moving PAD-clocks possesses the same time readout (ie they are not synchronised), and so they cannot be simultaneous when the 2 PAD-clocks possesses the same time readout, and the aether frame POV is always correct. Simultaneity is always dictated by only the aether POV.​

I know how SR works. Is my understanding of LET incorrect here? If so, it seems to me that "the PoR only appears to be upheld" under LET. That is, the balance beam would tip under LET, and the observer at rest in the aether frame would predict it. That is ... the balance should tip based upon simultaneous events, but not necessarily based upon like PAD-clock-time-readouts.

GrayGhost

 

[harrylin]

harrylinn,

When one says "wonder beam", most folks generally accept that the beam does something that cannot happen in relality, or at least in practice to date. No different from discussing a wonder-traveler who attains c, which everyone knows cannot happen. But just for the sake of point, let's assume a wonder beam.

A wonder beam creates a paradox in SR - just as a wonder signal at infinite speed. If you do want to discuss your paradox, please start a separate thread on that.

Well, I understand how SR handles my stated scenario. You skipped over that at first, and it remains clear that you are misreading it based on your prior response. [..]
GrayGhost

Sorry but evidently you did not understand my reply to you: According to the PoR the same laws of physics must be valid in any inertial frame, "ether" frame or not. Consequently, any problem that you imagine for "LET" is identical for standard SR, in which "ether frame" merely serves as a lable for a certain "rest frame". The laws of physics - even for moving balances (but not for wonder beams which break those laws) - must be valid wrt such a frame, as otherwise absolute inertial motion could be detected. The balance beam cannot tip according to the PoR, and both POV's must agree that the beam does not tip; that was the purpose of both Lorentz-1904 and Einstein-1905.

Note that in his 1904 paper Lorentz made one or two little errors, which made him unsure that the new theory perfectly obeyed the PoR; but that was soon straightened out by Poincare (and perhaps he answers your question clearer than I do!):
- http://en.wikisource.org/wiki/On_the_Dynamics_of_the_Electron_%28June%29

And for a primer to the light postulate and relativity of simultaneity, see (again!) a paper by Poincare (in XII and XIII, near the end):
http://en.wikisource.org/wiki/The_Measure_of_Time

 

[George Jones]

"Dismissing renewed attempts to deny Einstein the discovery of special relativity",

http://www.relatividadespecial.com/index.php?option=com_docman&task=doc_download&gid=24&Itemid=

 

[GrayGhost]

...

Harrylinn,

I never suggested any paradox exists. Far as the wonder beam simplication is concerned, if you prefer, you can simply assume it bends but does not break, and that there's nothing wonderful about it. I also never suggested that observers of differing frames would disagree as to whether the beam tips. I'm not sure where you get all this stuff, but you should really read posts more carefully before responding, because it just muddies the thread. What I was asking about was (1) did Lorentz force-fit his LT derivation to accommodate the PoR (you say no), and (2) does the PoR truly apply to the all-of-physics under LET, or does it apply only kinematically? From your last post, it seems that it applies period.

LET an SR are not the same theory. Some folks here claim that the theories are identical, except that any aether frame is superfluous per SR, and that it's impossible to detect the truly existent aether frame per LET. Light speed is defined differently per each theory. One theory says that what you measure matches what is real, while the other says length-contractions prevent your contracted ruler from measuring the true-contractions. It seems to me that there is more a difference between the 2 theories than these alone. Lorentz disagrees that 2 inertial clocks synchrionised-with-each-other moving thru the aether are "truely simultaneous" per themselves. Is this correct, or not?

GrayGhost

 

[Sybren]

As far as I know, Lorentz invented his transformations to account for the result of the Michelson-Morley interferometer experiment, in case of a luminiferous ether. The experimental setup was moving through the ether, he said, and it may possibly be a yet unknown property of electrons that they contract in the direction they are moving in through the ether. This would deform the interferometer setup in the right way to produce the observation. What he did here was come up with the necessary mathematical relation if you accept the experimental outcome, and accept the ether concept.

Einstein knew nothing about this experiment, and was studying Maxwell's equations, when he was considering the problem of a moving magnet and a conductor (moving magnet and conductor problem). When using Galilean transformations between the magnet frame and the conductor frame, the normal procedure at that moment, the calculated Lorentz force an an electron was identical in both cases. However, the electromagnetic fields producing the force were different. Although the Galilean transformation conserved the Lorentz force in this case, it did not conserve the Maxwells equations (as seen by substituting the Galilean-transformed fields into the Maxwell equations). At this point, it can be shown (I yet have to complete this part of the derivation) that there exists a transformation (non-Galilean) that conserves Maxwell's equations as well as the Lorentz force in both frames. This transformation equation is, in fact, the Lorentz transformation equation.

 

[PhilDSP]

LET an SR are not the same theory. Some folks here claim that the theories are identical, except that any aether frame is superfluous per SR, and that it's impossible to detect the truly existent aether frame per LET.

I think I agree with you on those points. If you don't delve into either the mathematics or the rationale of development deeply enough it seems reasonable to view the observables as equivalent, but that may be deceptive. Lorentz's theory is built around the concept of the invariance of the wave operator and the spatial deformation of an extended electron charge. It doesn't make any ad hoc postulates that force a redefinition of the metric relationships between space and time. It isn't necessarily limited to inertial frames and is therefore potentially more encompassing from a mathematical point of view, even to the point of potentially making an absolute frame of reference observable.

 

[Histspec]

What I was asking about was (1) did Lorentz force-fit his LT derivation to accommodate the PoR (you say no), and (2) does the PoR truly apply to the all-of-physics under LET, or does it apply only kinematically?

Maybe one has to look at the predictions of various kinematic and dynamic test theories of SR:

http://en.wikipedia.org/wiki/Test_theories_of_special_relativity"

For example, the Robertson-Mansouri-Sexl theory is a kinematic framework. Giving to the test-parameters their relativistic values, then (and only then) this "preferred frame theory" is experimentally indistinguishable from SR.
It becomes a little more complicated, when one uses more extensive test theories like the

http://en.wikipedia.org/wiki/Standard-Model_Extension" .

This model includes a bunch of parameters, which also apply to dynamics. Of course, also in this model, a suitable combination of the parameters leads to a "preferred frame theory" experimentally indistinguishable from SR, but the probability of such a theory is extremely small due to the large number of ad hoc hypotheses required.

So, in summary: I think it's always possible to modify "LET" so that it is experimentally equivalent to SR. However, the increasing number of effects that must be explained, decreases the probability of such a theory.

Regards,

 

[harrylin]

Harrylinn,
I never suggested any paradox exists.
[..] I also never suggested that observers of differing frames would disagree as to whether the beam tips.

Indeed it was not you but me who suggested that your example is a paradox (=apparent contradiction): I actually understood that according to you, "the observer at rest in the aether frame would predict" that "the balance beam would tip", while according to "observers at rest with the balance" "the balance beam would not tilt". Sorry that I misunderstood you.

That would be perfectly incompatible with Poincare's 1905 summary to which I gave a link:

Lorentz [managed to] bring [his hypothesis] into accord with the postulate of the complete impossibility of determining absolute motion [..] in his article entitled Electromagnetic phenomena in a system moving with any velocity smaller than that of Light (Proceedings de l’Académie d’Amsterdam, May 27, 1904).

[...] LET an SR are not the same theory.
Some folks here claim that the theories are identical, except that any aether frame is superfluous per SR, and that it's impossible to detect the truly existent aether frame per LET. Light speed is defined differently per each theory. One theory says that what you measure matches what is real, while the other says length-contractions prevent your contracted ruler from measuring the true-contractions. It seems to me that there is more a difference between the 2 theories than these alone. Lorentz disagrees that 2 inertial clocks synchrionised-with-each-other moving thru the aether are "truely simultaneous" per themselves. Is this correct, or not?
GrayGhost

As I already mentioned, according to Einstein a new theory emerged with the writings of Lorentz in 1904 and his own in 1905; I agree with that. However there is a subtle difference between the two interpretations of the theory: whereas Lorentz found it useful to distinguish between what appears to happen and what "really" happens from an unknown perspective that cannot be detected, Einstein found it better to only discuss the phenomena (=appearances, not what "truly" happens!).

 

[GrayGhost]

Indeed it was not you but me who suggested that your example is a paradox (=apparent contradiction): I actually understood that according to you, "the observer at rest in the aether frame would predict" that "the balance beam would tip", while according to "observers at rest with the balance" "the balance beam would not tilt". Sorry that I misunderstood you.

No problem. I thank you for doubling back for reread.

As I already mentioned, according to Einstein a new theory emerged with the writings of Lorentz in 1904 and his own in 1905; I agree with that. However there is a subtle difference between the two interpretations of the theory:

whereas Lorentz found it useful to distinguish between what appears to happen and what "really" happens from an unknown perspective that cannot be detected, Einstein found it better to only discuss the phenomena (=appearances, not what "truly" happens!).

Well, sounds about right. Now please understand that I am not just trying to argue here, but two points that I feel are debatable ...

(1) as to whether Lorentz and Einstein have 2 interpretations of a same theory. I've always considered the theories to differ, so 2 differing theories that happen to possesses the same solutions.

(2) as to whether Einstein's comments as-to-what "appears to be" means "possibly untrue". From my studies of OEMB, my impression is that Einstein discusses what is measurable/recordable by observers using light itself as part of the measuring apparatus. In Einstein's theory, an extension of rigid coordinate system axes would be consistent with relativistic measurements using light signals. In this sense, what is measured matches what is real, per any inertial measurer. The fact that OEMB requires a moving observer contract and his moving clock slow down, while yet said moving-observer never measures/discerns any change in his own length or clock rate, does not necessarily lead that Einstein assumed relativistic effects are "not true".​

I'm just trying to get to the core of "the differences in meaning" between SR and LET, and as to whether the PoR is upheld (for the all of physics) in LET as well as it is upheld in SR. I've never fully understood the full meaning of LET, mainly because "folks who understand LET well" often tend to make differing statements about its deeper meaning. By "deeper meaning", I refer to those concepts upon which the theory is constructed, and as to how they impact the meaning of the final LT solns (the LTs being the same in both theories).

Just a couple related points on this, per http://en.wikipedia.org/wiki/Lorentz_ether_theory" ...

In 1904 he (Poincare) illustrated the same procedure in the following way: A sends a signal at the time 0 to B, which arrives at the time t. B also sends a signal at the time 0 to A, which arrives at the time t. If in both cases t has the same value the clocks are synchronous, but only in the system in which the clocks are at rest in the ether. So according to Darrigol Poincaré understood local time as a physical effect just like length contraction - in contrast to Lorentz, who used the same interpretation not before 1906. However, contrary to Einstein, who later used a similar synchronisation procedure which was called Einstein synchronisation, he still was the opinion that only clocks resting in the ether are showing the "true" time.

In 1907 Einstein criticized the "ad hoc" character of Lorentz's contraction hypothesis in his theory of electrons, because according to him it was only invented to rescue the hypothesis of an immobile ether. Einstein thought it necessary to replace Lorentz's theory of electrons by assuming that Lorentz's "local time" can simply be called "time", and he stated that the immobile ether as the theoretical fundament of electrodynamics was unsatisfactory.​

So Einstein saw Lorentz's "local time" as "time", which suggests to me "true time". This is no different from saying that the readout of a distant moving clock is the true time of said moving clock, per the observer. IOWs, it's not some kind of luminal effect that produces a moving time readout that is less-than-real.

GrayGhost

 

[harrylin]

[..]two points that I feel are debatable ...

(1) as to whether Lorentz and Einstein have 2 interpretations of a same theory. I've always considered the theories to differ, so 2 differing theories that happen to possesses the same solutions.​

As I and Pallen discussed early in this thread, it's a bit funny that people treat such questions regarding QM differently. I still don't fully understand why. Would you argue that there are different theories* of QM? Or is this all just word games perhaps?

(2) as to whether Einstein's comments as-to-what "appears to be" means "possibly untrue". From my studies of OEMB, my impression is that Einstein discusses what is measurable/recordable by observers using light itself as part of the measuring apparatus. In Einstein's theory, an extension of rigid coordinate system axes would be consistent with relativistic measurements using light signals. In this sense, what is measured matches what is real, per any inertial measurer. The fact that OEMB requires a moving observer contract and his moving clock slow down, while yet said moving-observer never measures/discerns any change in his own length or clock rate, does not necessarily lead that Einstein assumed relativistic effects are "not true".

I don't know what you mean with "OEMB", but it sounds as if you mean with "real" something else than what for example Newton meant with "real" or "true". In any case, you can easily verify that Einstein's 1905 paper avoids those words altogether; and I am sure that was on purpose. Definitely such non-measurables are not part of SR.

I'm just trying to get to the core of "the differences in meaning" between SR and LET, and as to whether the PoR is upheld (for the all of physics) in LET as well as it is upheld in SR. I've never fully understood the full meaning of LET, mainly because "folks who understand LET well" often tend to make differing statements about its deeper meaning.

The funny thing is that Lorentz himself probably did not know about this "LET" that you discuss here; a long time ago when I tried to find its origin, I found that it almost certainly originated from a confusion by Minkowski - a confusion that has lived on until today, as so often happens.

By "deeper meaning", I refer to those concepts upon which the theory is constructed, and as to how they impact the meaning of the final LT solns (the LTs being the same in both theories). [..Wikipedia..]

Let's not discuss the mix of accuracies and inaccuracies of Wikipedia on this forum; please stick with the original (mostly peer-reviewed) papers!

So Einstein saw Lorentz's "local time" as "time", which suggests to me "true time". This is no different from saying that the readout of a distant moving clock is the true time of said moving clock, per the observer. IOWs, it's not some kind of luminal effect that produces a moving time readout that is less-than-real.
GrayGhost

I'm sorry but I can't make sense of what you mean with "true": you appear to have no problem with contradictory truth, so that your definition of "true" is close to my definition of "untrue"; and I think that we had that same problem in an earlier thread, and that we could not solve it. So I won't try again. In any case, "true" is not defined in SR. SR is about predictions and observations.

* See: https://www.physicsforums.com/showthread.php?t=489958&highlight=poll

Regards,
Harald

 

[Doc C PhDo]

Appears that as Lorentz was striving to present his 'electrical theory of matter'. He developed
his transform: x' = x - [ vt/SquareRoot( 1 - (v^2/c^2))], c the velocity of light. ----- Because of the enigma of 'length contraction' and the Michelson-Morley 'failure' (no aether detected).
Lorentz suggested, regarding relative motion; that if you 'hold' c as the/a constant and arbitrarily make space and time variables; his equation accounts for 'length contraction'.

 

[GrayGhost]

As I and Pallen discussed early in this thread, it's a bit funny that people treat such questions regarding QM differently. I still don't fully understand why. Would you argue that there are different theories* of QM? Or is this all just word games perhaps?

Well, I would say that there is one QM theory, but that there exists various interpretations of the theory. The varying interpretations come from trying to explain the meaning of things such as (say) the wave function collapse.

Here though, we've been talking about 2 different theories, LET and SR, which just happens to have the same LT solns. Their foundations differ.

I don't know what you mean with "OEMB", but it sounds as if you mean with "real" something else than what for example Newton meant with "real" or "true". In any case, you can easily verify that Einstein's 1905 paper avoids those words altogether; and I am sure that was on purpose. Definitely such non-measurables are not part of SR.

I suppose it best to replace "real" with the word "measured/measurable", for otherwise folks often tend to use that to send the discussion off track and out into left field. In LET though, it's not so easy. We have (in LET) the issue of a moving contracted ruler not able to measure itself as contracted because it too length-contracts by the same amount, which seems a "less than real" measurement. It's contracted, but it cannot tell. In SR, inertial rulers cannot measure themselves contracted because they aren't, because no contractions exist when stationary, and so different story altogether.

The funny thing is that Lorentz himself probably did not know about this "LET" that you discuss here; a long time ago when I tried to find its origin, I found that it almost certainly originated from a confusion by Minkowski - a confusion that has lived on until today, as so often happens. Let's not discuss the mix of accuracies and inaccuracies of Wikipedia on this forum; please stick with the original (mostly peer-reviewed) papers!

Well, maybe so. I am not sure as yet, myself. I now see your position on this matter, but I've read much over the years that contends otherwise. I'll have to look online for some verification. It reminds me of the democrat who says FOX news has unreputable sources, and the republican who says CNN has unreputable sources :) I'd like to see some statements made by Lorentz himself, between 1904 and (say) 1908, and after.

I'm sorry but I can't make sense of what you mean with "true": you appear to have no problem with contradictory truth, so that your definition of "true" is close to my definition of "untrue"; and I think that we had that same problem in an earlier thread, and that we could not solve it. So I won't try again. In any case, "true" is not defined in SR. SR is about predictions and observations.

In the context of SR, my definition of true is "measured". I'm not so sure that this definition apply as well to LET though, as I stated prior here.

GrayGhost

 

[GrayGhost]

So, in summary: I think it's always possible to modify "LET" so that it is experimentally equivalent to SR. However, the increasing number of effects that must be explained, decreases the probability of such a theory. Regards,

Sounds rather reasonable to me. However the fact that these "increased number of effects" need be explained in LET, suggests to me that the meaning of the LTs likely differs for SR vs LET ... even though the solns are the same. no?

GrayGhost

 

[Histspec]

Let's not discuss the mix of accuracies and inaccuracies of Wikipedia on this forum; please stick with the original (mostly peer-reviewed) papers!

I'm sorry but I can't make sense of what you mean with "true": you appear to have no problem with contradictory truth, so that your definition of "true" is close to my definition of "untrue"; and I think that we had that same problem in an earlier thread, and that we could not solve it. So I won't try again. In any case, "true" is not defined in SR. SR is about predictions and observations.

The Wikipedia article is correct. It was Lorentz himself, who used the word "true time" to distinguish his own views from that of Einstein and Minkowski (and Poincaré). For example in 1914: http://en.wikisource.org/wiki/Two_Papers_of_Henri_Poincar%C3%A9_on_Mathematical_Physics, p. 252, emphasis by me:

The formulas (4) and (7) are not in my memoir of 1904. Because I had not thought of the direct way which led there, and because I had the idea that there is an essential difference between systems x, y, z, t and x',y',z',t'. In one we use - such was my thought - coordinate axes which have a fixed position in the aether and which we can call "true" time; in the other system, on the contrary, we would deal with simple auxiliary quantities whose introduction is only a mathematical artifice. In particular, the variable t' could not be called "time" in the same way as the variable t....Poincaré, on the contrary, obtained a perfect invariance of the equations of electrodynamics, and he formulated the "postulate of relativity".

So Lorentz clearly wrote, that the shortcomings of his 1904-paper are the consequence of his distinction between "true" time in the aether; and "local" time which is only a "mathematical artifice".

Or in 1910: http://de.wikisource.org/wiki/Das_Relativitätsprinzip_und_seine_Anwendung, p. 75, (translation and emphasis by me):

Provided that there would exist an aether: then one of all systems x, y, z, t, would be preferred by the fact that the coordinate axes as well as the clocks are resting in the aether. If one connects with this the idea (which I only reluctantly would abandon) that space and time be completely different things, and that there be a "true time" (simultaneity thus would be existing independently, corresponding to the fact, that it is possible for us to imagine infinitely great speeds), then one can easily see, the this true time shall be indicated by clocks at rest in the aether. Now, if the relativity principle had general validity in nature, however, one would consequently be unable to find out whether the reference system momentarily employed is that preferred one. Thus one arrives at the same results, as when one denies the existence of the aether and of true time, and to view all reference systems as equally valid, following Einstein and Minkowski. To which of both ways of thinking one adheres to, we can leave to the judgment of each individual.

So on one hand, we have Lorentz's view that there is a "preferred frame", "absolute simultaneity" and "true time", but all of them are unobservable. And we have Einstein and Minkowski, according to which all of those concepts are meaningless.

And the same in 1913: http://de.wikisource.org/wiki/Das_Relativitätsprinzip_(Lorentz)), p. 23, (translation and emphasis by me):

If the observers would like to view the concept of time as something primary, something completely separated from the concept of space, then they would surely recognize, that absolute simultaneity exists; however, they would leave it undecided again, whether this simultaneity is indicated by equal values of t, or by equal values of t', or maybe neither by one nor the other.
Einstein says in short, that all questions mentioned before, have no meaning. Thus he arrives at the abolishment of the aether. The latter is, by the way, to some extent a quarrel about words: it makes no great difference, whether one speaks of vacuum or aether. Anyway, according to Einstein it has no meaning to speak about a motion relative to the aether. He also denies the existence of absolute simultaneity.
It is certainly remarkable, that those relativity concepts, even with respect to time, have been adopted so fast.
The evaluations of those concepts mostly belong to epistemology, and one can leave it to its judgment, trusting that it considers the questions discussed with the thoroughness required. However, it is for sure, that for a large part it will depend on the way of thinking to which one is accustomed, whether one is mostly attracted to one or the other view. Regarding the lecturer himself, he finds a certain satisfaction in the elder views, that the aether at least possesses some substance, that space and time can sharply be separated, and that one can speak of simultaneity without closer specification. Regarding the latter, one can maybe rely on our ability, to (at least) imagine arbitrary great speeds. By that, one comes very near to the concept of absolute simultaneity.

Regards,

 

[harrylin]

Well, I would say that there is one QM theory, but that there exists various interpretations of the theory. The varying interpretations come from trying to explain the meaning of things such as (say) the wave function collapse.

Here though, we've been talking about 2 different theories, LET and SR, which just happens to have the same LT solns. Their foundations differ.

QM had multiple philosophical foundations relating to differing philosophies as locality, no locality, particles, waves and wave-particles; differing interpretations have been there right from the beginning. The "solution" of modern theories of physics such as SR and QM is to formulate them in such a way that they discuss only observables.

I refer you again to Einstein's overview of 1907 of what he later named SR: its foundation is the construction of a theory in which Maxwell's equations are invariant for a change of inertial reference system, so that the PoR is valid for all laws of physics. The unification of Lorentz's Theory of Electrons with the principle of relativity was the common basis for Lorentz-1904 and Einstein-1905.

[..] In SR, inertial rulers cannot measure themselves contracted because they aren't, because no contractions exist when stationary [..]

Those rulers are contracted according to any observer who is moving wrt to them while you say that "they arent"... if you want to suggest with that that the POV of that observer is "wrong" - that is at odds with the PoR. The whole point of the PoR is that such claims can not be made. But I'm sure that we have been here before, it's perhaps a difference of how are brains are wired.

I'd like to see some statements made by Lorentz himself, between 1904 and (say) 1908, and after.

Mere statements won't suffice as they should be understood in context; a whole section is more reliable than a sound bite. You can find increasingly more original papers of that time in Wikisources to which I already gave links:
http://en.wikisource.org/wiki/Portal:Relativity

In the context of SR, my definition of true is "measured". I'm not so sure that this definition apply as well to LET though, as I stated prior here.
GrayGhost

Certainly Lorentz meant with "true" not what is measured but invisible reality, like Newton.

 

[harrylin]

Sounds rather reasonable to me. However the fact that these "increased number of effects" need be explained in LET, suggests to me that the meaning of the LTs likely differs for SR vs LET ... even though the solns are the same. no?

GrayGhost

It depends on what you mean with "LET", and with "the LTs". They don't exist in that form in the 1904 paper by Lorentz, and he had not thought enough about the meaning in practice of his "local time". However, in the 1905 paper by Poincare the meaning of the equations is the same as it is today.

 

[harrylin]

The Wikipedia article is correct. [..]

Nothing is perfect and certainly not Wikipedia! I referred to suggestions of that article (not related to your citations) that were cited here.

Anyway, thanks for the many citations.

I note that you forgot to include citations of Einstein's 1918 and 1920 replies in which he abandoned his earlier interpretation; but all that has little to do with the topic.

Regards,
Harald

 

[GrayGhost]

It depends on what you mean with "LET", and with "the LTs". They don't exist in that form in the 1904 paper by Lorentz, and he had not thought enough about the meaning in practice of his "local time". However, in the 1905 paper by Poincare the meaning of the equations is the same as it is today.

OK harrylin. So Lorentz derived the correct LT solns first in 1904, although he did not understand the meaning of time t', ie time dilation. Poincare made a correction to the 2004 LET in 2005 (wrt electric charge), and also re-interpreted Lorentz's LET in a way that allowed it finally become Lorentz covariant ... whereby Lorent'z provided a physical meaning for Lorentz's "local time", versus some mathematical artifact during derivation. So in the same year, 2005, we have Poincare's re-interpretation of LET and Einstein's OEMB published. Lorentz finally began accepting Poincare's re-interpretation in 2006. Einstein's theory was accepted over LET because of simplicity, the result of an invariant light speed ... ie, a choice of convention that makes everything more convenient. Sound about right?

I must say, it remains strange to me that we have one theory that begins from a preferred aether frame, and another theory that assumes no preferred frame exists, and the solns are identical with both supporting the PoR. If so, would this not be true ... Wouldn't any arbitrary inertial frame be able to be defined as the preferred aether frame, and if so, would not the very same LTs arise during the same Lorentz derivation? I mean if no experiment can determine the aether frame (or distinguish LET from SR), then I suppose it matters not which frame you begin with "as the aether frame". Yes? I mean the end results are the very same. And if it doesn't matter, then one has to wonder whether there really is an aether frame at all (even if an aether exists). So I still seem to be missing something about LET here, but I don't yet know what it is :)

GrayGhost

 

[harrylin]

OK harrylin. So Lorentz derived the correct LT solns first in 1904, although he did not understand the meaning of time t', ie time dilation. Poincare made a correction to the 2004 LET in 2005 (wrt electric charge), and also re-interpreted Lorentz's LET in a way that allowed it finally become Lorentz covariant ... whereby Lorent'z provided a physical meaning for Lorentz's "local time", versus some mathematical artifact during derivation. So in the same year, 2005, we have Poincare's re-interpretation of LET and Einstein's OEMB published. Lorentz finally began accepting Poincare's re-interpretation in 2006. Einstein's theory was accepted over LET because of simplicity, the result of an invariant light speed ... ie, a choice of convention that makes everything more convenient. Sound about right?

That sounds almost right to me.
However:
- You placed the events it in the wrong century.
- Poincare as well as Langevin were not mistaken or cheating when they claimed that Lorentz managed to create what you here call a "Lorentz covariant" theory: the Lorentz transformations follow directly from Lorentz's 1904 paper without any correction and with the modern operational meaning.
- Lorentz had already mentioned the physical meaning of time dilation in an earlier paper and he certainly understood the fact that the PoR of classical mechanics implies that the corresponding transformations hold just as well between moving systems; thus there was no need for him to "begin accepting" Poincare's interpretation. It was simply that by 1904, in his head "all the pennies had not yet dropped".

Note that the phrase "they form a group" is very mathematical and Poincare was also a mathematician. However it was not a common thing to say for physicists at that time. I think that Lorentz did not use that expression. Consequently the fact that Einstein put that phrase in his paper has been advanced as evidence for the hypothesis that he had seen Poincare's paper. However, that's irrelevant for the priority of the 1904 and 1905 papers of Lorentz and Poincare.

I must say, it remains strange to me that we have one theory that begins from a preferred aether frame, and another theory that assumes no preferred frame exists, and the solns are identical with both supporting the PoR.

Ehm, not exactly. It's similar to classical mechanics vs. Newton's mechanics. Both Lorentz-1904 and Einstein-1905 begin from the PoR, which implies that no frame is preferred for the phenomena. Lorentz's derivation starts from a "true" (or "absolute") rest frame which cannot be determined, while Einstein's derivation omits that assumption because it is "superfluous" for the derivations: it plays no role in the predictions that are based on the postulates. However, the light postulate corresponds to the Maxwell-Lorentz wave theory of light, as opposed to ballistic light theories (see further).

If so, would this not be true ... Wouldn't any arbitrary inertial frame be able to be defined as the preferred aether frame, and if so, would not the very same LTs arise during the same Lorentz derivation? I mean if no experiment can determine the aether frame (or distinguish LET from SR), then I suppose it matters not which frame you begin with "as the aether frame". Yes? I mean the end results are the very same. And if it doesn't matter, then one has to wonder whether there really is an aether frame at all (even if an aether exists). So I still seem to be missing something about LET here, but I don't yet know what it is :)

GrayGhost

Exactly - such a "frame" is not "preferred" in that sense.
What you may have missed, is the wish of many physicists to come up with a physical model of light propagation (even if just a sketchy concept like the atom for the ancient Greeks), so as to be able to ascribe a physical cause for such things as a limit speed, electromagnetic fields, etc*. It's similar to Einstein's later wish for a "local-realistic" physical explanation of the apparent "spooky action at a distance" of QM.

*Einstein motivated the light postulate as follows in 1907:

[this] "principle of the constancy of the velocity of light," is at least for a coordinate system in a certain state of motion [..] made plausible by the confirmation through experiment of the Lorentz theory [of 1895], which is based on the assumption of an ether that is absolutely at rest.

- German original: http://www.soso.ch/wissen/hist/SRT/E-1907.pdf

Regards,
Harald

 

[Histspec]

- Poincare as well as Langevin were not mistaken or cheating when they claimed that Lorentz managed to create what you here call a "Lorentz covariant" theory: the Lorentz transformations follow directly from Lorentz's 1904 paper without any correction and with the modern operational meaning.

Unfortunately, Lorentz himself said that he didn't arrive at a fully Lorentz covariant theory, due to his assumption, that there is a fundamental difference between "true" and "local" time. (see his Poincaré-paper above). So it's quite clear that Langevin and Poincaré were very generous in his assessment. See also Lorentz's remark: http://en.wikisource.org/wiki/Two_Papers_of_Henri_Poincar%C3%A9_on_Mathematical_Physics

Poincaré, on the contrary, obtained a perfect invariance of the equations of electrodynamics, and he formulated the "postulate of relativity", terms which he was the first to employ. Indeed, stating from the point of view that I had missed, he found the formulas (4) and (7). Let us add that by correcting the imperfections of my work he never reproached me for them.

Here is another statement of Lorentz from 1928, p. 350: http://adsabs.harvard.edu/abs/1928ApJ%E2%80%A6.68..341M

A transformation of time was also necessary. So I introduced the conception of a local time which is different for different systems of reference which are in motion relative to each other. But I never thought that this had anything to do with the real time. This real time for me was still represented by the old classical motion of an absolute time, which is independently of any reference to special frames of co-ordinates. There existed for me only this one true time. I considered my time transformation only as a heuristic working hypothesis. So the theory of relativity is really solely Einstein's work. And there can be no doubt that he would have conceived it even if the work of all his predecessors in the theory of this field had not been done at all. His work is in this respect independent of the previous theories.

However, one may wonder that in one text he referred to Einstein, and in another to Poincaré...

Lorentz had already mentioned the physical meaning of time dilation in an earlier paper and he certainly understood the fact that the PoR of classical mechanics implies that the corresponding transformations hold just as well between moving systems; thus there was no need for him to "begin accepting" Poincare's interpretation. It was simply that by 1904, in his head "all the pennies had not yet dropped".

Not according to Lorentz's own opinion. He had the local time formula in 1892, and the time-dilation formula in 1899, but as he himself noticed, this was only a "mathematical artifice" (see his Poincaré-paper or the quote given above). It was not before 1906, when he first spoke about a physical interpretation of both "local time" and "time dilation" by using clocks.
In fact, the light-signal interpretation of local time was first given by Poincaré in 1900, and the transported-clock interpretation of time-dilation was first given by Larmor and Cohn in 1904.

Einstein motivated the light postulate as follows in 1907:
- German original: http://www.soso.ch/wissen/hist/SRT/E-1907.pdf

[this] "principle of the constancy of the velocity of light," is at least for a coordinate system in a certain state of motion [..] made plausible by the confirmation through experiment of the Lorentz theory [of 1895], which is based on the assumption of an ether that is absolutely at rest.

Yes, Lorentz's aether theory influenced Einstein's thinking on the light postulate – but he didn't used the aether concept itself. See p. 413. (translation and emphasis by me)

However, it was demonstrated surprisingly, that it was only necessary to define the concept of time sufficiently precise, to overcome the difficulty discussed before. Only the idea was necessary, that an auxiliary quantity introduced by H. A. Lorentz, which was denoted by him as "local time", can be defined as "time" per se. If one continues to adhere to the sketched definition of time, then the fundamental equations of Lorentz's theory correspond to the relativity principle, when one replaces the transformation equations above, by such ones corresponding to the new concept of time. The hypothesis of H. A. Lorentz and Fitzgerald then appears to be as a necessary consequence of the theory. Only the idea of a luminiferous aether as the carrier of electric and magnetic forces does not fit into the theory laid out here; namely, electromagnetic fields doesn't appear here as states of some sort of matter, but as independently existing things, that are equally valid to ponderable matter and share with it the property of inertia.

Regards,

 

[GrayGhost]

Histspec,

Well, you do seem to have your sources. Thanx for the references.

My understanding was that Einstein continued working as a patent clerk from 1904 thru 1908, so for 4 more years, before being approached by colleagues of Max Planck. I'm just curious, at what year did Lorentz (and/or Poincare) first become aware of Einstein's 1905 paper? Any idea?

GrayGhost

 

[harrylin]

Unfortunately, Lorentz himself said that he didn't arrive at a fully Lorentz covariant theory, due to his assumption, that there is a fundamental difference between "true" and "local" time. (see his Poincaré-paper above). So it's quite clear that Langevin and Poincaré were very generous in his assessment. See also Lorentz's remark: http://en.wikisource.org/wiki/Two_Papers_of_Henri_Poincar%C3%A9_on_Mathematical_Physics

Generous perhaps, but basically correct since the Lorentz transformations follow directly from Lorentz-1904. It appears that people who more openly proclaim their mistakes and weaknesses are punished for their honesty. Due to lack of rigour (instead of "proceeding more systematically") Lorentz's electromagnetic formulas "remained encumbered with certain terms which should have disappeared".
Note that similarly, there's an error in the transverse mass equation of Einstein-1904: a square root is lacking there (http://www.fourmilab.ch/etexts/einstein/specrel/www/, it's the same in the German original; for a discussion see E. Cullwick, The British Journal for the Philosophy of Science Vol. 32, No. 2, Jun., 1981, http://www.jstor.org/stable/687198?seq=6).

Usually one does not trash a theory because of a few glitches in the original papers; but of course that's a matter of opinion.

Here is another statement of Lorentz from 1928, p. 350: http://adsabs.harvard.edu/abs/1928ApJ%E2%80%A6.68..341M

However, one may wonder that in one text he referred to Einstein, and in another to Poincaré...

Indeed - although by then "theory of relativity" commonly referred to GR, it appears that with "theory of relativity" he there referred to special relativity, in which case his accreditation was simply faulty. It could be amnesia due to old age (it was shortly before his death and these are conversation notes); or perhaps it was due to an editing error. Although Lorentz supposedly reviewed those shorthand notes, he may have overlooked the error.

harrylin wrote: "Lorentz had already mentioned the physical meaning of time dilation in an earlier paper and he certainly understood the fact that the PoR of classical mechanics implies that the corresponding transformations hold just as well between moving systems; thus there was no need for him to "begin accepting" Poincare's interpretation. It was simply that by 1904, in his head "all the pennies had not yet dropped"."

Not according to Lorentz's own opinion. [...]

Lorentz never stated that he did not understand that the Galilean transformations conform to the classical PoR so that they are valid between inertially moving systems; indeed that would be rather incredible.

And with the "physical meaning" of time dilation I had his 1899 paper in mind:

Michelson's experiment should always give a negative result, whatever transparent media wore placed on the path of the rays of light, [..] provided however that in S the time of vibration be kε times as great as in S0.

- http://en.wikisource.org/wiki/Simpl...rical_and_Optical_Phenomena_in_Moving_Systems

A mere calculation aid cannot affect such a physical vibration time.

Yes, Lorentz's aether theory influenced Einstein's thinking on the light postulate – but he didn't used the aether concept itself. See p. 413. (translation and emphasis by me)
Regards,

Yes, and I wondered what he meant with "an ether as carrier of electric and magnetic forces does not fit in that model"; but happily in 1920 Einstein clarified his 1907 claim as follows:

H. A. Lorentz [..] brought theory into harmony with experience by means of a wonderful simplification of theoretical principles. He achieved this [..] by taking from ether its mechanical [..] qualities. [...] According to Lorentz the elementary particles of matter alone are capable of carrying out movements; their electromagnetic activity is entirely confined to the carrying of electric charges.

Note: I'm afraid that this discussion has drifted rather far from the topic; and I think that the questions of the OP have been more than sufficiently answered. Thus I'll abstain from further commenting on aspects that are not perfectly on topic.

Regards,
Harald

PS more references for the question "who first derived SR" can be found here:
http://en.wikipedia.org/wiki/Relativity_priority_dispute

 

[GrayGhost]

harrylin,

Indeed, it helps to get the century right :) Thanx for the correction.

It seems clear as to why SR was accepted over LET. LET assumes an immovable aether that can never be found, a preferred frame, a non-invariant light speed that cannot be recorded, and physically contracted rulers that can never measure their own contraction. SR has none of these issues. Yet, I suppose there is always the possibility that an aether frame does exist, as assumed per the LET model. It seems more intuitive to me that if an aether frame does exist, it be an unpreferred inertial frame of Einstein's model as opposed to Lorentz's undeterminable preferred one. BTW, would not the determination of the 1-way speed of light reveal which theory is the correct one?

GrayGhost