Did Lorentz or Einstein theoretically derive special relativity?

[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

 

[Samshorn]

...there's an error in the transverse mass equation of Einstein-1904: a square root is lacking there...

No, that's a misconception. There's no "error" in Einstein's transverse mass equation in the 1905 paper. See, for example, this discussion of that issue:

http://www.mathpages.com/home/kmath674/kmath674.htm

 

[harrylin]

harrylin,

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

[...] 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

There must be a misunderstanding here: Lorentz's ether corresponds to an unpreferred inertial frame. I did elaborate on that issue (and I won't again, as it's not the topic).

About the 1-way speed of light: the answer is no that makes in principle no difference with the two-way speed of light. That was even understood well before SR; for example discussed in the paper by Poincare that I referred you to in post no. #29

 

[harrylin]

No, that's a misconception. There's no "error" in Einstein's transverse mass equation in the 1905 paper. See, for example, this discussion of that issue:

http://www.mathpages.com/home/kmath674/kmath674.htm

Interesting, he disagrees with Cullwick (+reviewers). I'm afraid that mathpages is not reviewed (and thus in principle illegal here), but usually they are of high quality. I'll read it with interest.

 

[GrayGhost]

There must be a misunderstanding here: Lorentz's ether corresponds to an unpreferred inertial frame. I did elaborate on that issue (and I won't again, as it's not the topic).

Well, there seems to be differing versions of Lorentz's beliefs. I'll dig further into both camps, see what evolves in that respect.

About the 1-way speed of light: the answer is no that makes in principle no difference with the two-way speed of light. That was even understood well before SR; for example discussed in the paper by Poincare that I referred you to in post no. #29

Yes, but I was not talking the 2-way speed of light. If in fact the 1-way speed of light were accurately measurable, that should tell the story as to whether the aether obeys Einstein's model vs Lorentz's. Why would a detection of the 1-way speed of light not be useful in distinguishing which theory possesses the correct foundation?

GrayGhost

 

[Zentrails]

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

I've also read that Einstein learned of the Michaelson-Morley experiment long after he published his SR paper.

Can someone explain to me why that would be important to Einstein? Wouldn't he consider the Earth to be one big inertia frame of reference and expect the speed of light to be the same in both directions for that reason alone?

I've never quite understood why that experiment would have anything to do with SR. (I got my MS at CWRU and have seen their experimental setup - fascinating stuff).

Didn't the fact that the speed of light as measured from occluded light sources far out in space all came to the same speed have much more relevance? Did Einstein know about those measurements?

 

[GrayGhost]

I've also read that Einstein learned of the Michaelson-Morley experiment long after he published his SR paper.

Indeed, that's reportedly what Einstein stated himself over his lifetime.

Can someone explain to me why that would be important to Einstein? Wouldn't he consider the Earth to be one big inertia frame of reference and expect the speed of light to be the same in both directions for that reason alone?

Well, I'd imagine that would have been important to him had he known about it. I mean it is a test of light speed invariance even though it was not intended as such, invariance being a cornerstone of Einstein's belief at the time and a postulate of his OEMB. My understanding is that Einstein believed light's speed invariant at c based off Maxwell's theory alone. There had been other tests of light speed prior to MMX, but I don't think the test setup apparatus' were sensitive enough to obtain the accuracy needed to see an aether drift. The MMX experiment was the first to attain the accuracy necessary.

I've never quite understood why that experiment would have anything to do with SR. (I got my MS at CWRU and have seen their experimental setup - fascinating stuff).

The MMX experiment was setup to detect the Earth's motion wrt the aether. The null result suggested there was no aether wind. Fitzgerald later realized that an invariant light speed would lead to length contraction of an interferometer arm(s) wrt the axis of motion. This could then explain why no fringe effect was noted in the MMX. So a relation between MMX and SR (or LET) is an invariant 2-way light speed ... an interpretation of no aether drift in the MMX, determined by LET, and postulated in SR.

Didn't the fact that the speed of light as measured from occluded light sources far out in space all came to the same speed have much more relevance? Did Einstein know about those measurements?

Not sure. However, you're talking about light's 1-way speed over long cosmic distances here. I'm not aware of any valid 1-way light speed test to date myself, but I think DaleSpam mentioned one to me recently. There was Romer's test using Jupiter's moon back in the 1600s, but not accurate by today's standards of course. If there are such tests, it would seem that the clock synchronisation convention selected would dictate the speed of light determined. Einstein indeed (in 1905) assumed a 1-way speed of light at invariant c, so he would have assumed all light to approach from distant sources at c, because he'd have used his own convention.

GrayGhost

 

[PhilDSP]

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

Those points are considered exactly in the article "Light Signals Sent Around a Closed Path", Journal of the Optical Society of America, April 16, 1938 by Herbert Ives. He analyzes what we now call ring laser experiments where 2 different signals are sent in opposite directions around a closed path and meet at a common point where the emitter-detector lies. The detector is an interferometer recording a difference in phase that occurs when the emitter-detector is set in motion along the same path as one of the signals.

The difference in phase depends on the velocity of the emitter-detector and on the area of the loop. The experiment usually involves rotation but rotation can be eliminated by placing the apparatus on a conveyor belt, for instance as Ives wrote. It is effectively 2 one way signals that are being compared. The circuit is often circular but Ives shows that the circuit and travel of the emitter-detector can consist of 4 straight segments with 4 mirrors.

The results clearly indicate that light travels through space at velocity c in a manner where space is resting with regard to the motion of the emitter and detector in the case where the path of light is not linear between the emitter and detector. I don't see how it is possible to resolve the difference in the apparent or measured speed of light with the fact that the relative velocity between the emitter and detector is zero unless some type of absolute reference system is established.

 

[Histspec]

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?

I'm quite sure, that Lorentz knew of Einstein's paper at the beginning of 1906. Because around that time, Kaufmann published the results of the http://en.wikipedia.org/wiki/Kaufmann%E2%80%93Bucherer%E2%80%93Neumann_experiments" .

http://en.wikisource.org/wiki/On_the_Constitution_of_the_Electron_(1905)

http://en.wikisource.org/wiki/On_the_Constitution_of_the_Electron_(1906)

Now, in these papers, Einstein is mentioned for the first time. Not only this: The latter paper also contains a comparison between the theories of Lorentz and Einstein. Kaufmann wrote:

It is now very remarkable, that, starting from quite different assumptions, Einstein recently arrived at results, which are in agreement with those of Lorentz concerning the consequences accessible to observation, though in which the previously mentioned difficulties of epistemological kind have been avoided. Einstein introduced the principle of relative motion, at least as regards translations, as a postulate. He thus places the theorem at the top, that physical phenomena observable in any rigid system, must be independent from whether the system (together with the observer) is moving relatively to any other system.

Since we know, that Lorentz was well acquainted with Kaufmann's papers, it's clear that he was therefore also aware of Einstein's theory in 1906.

As regards Poincaré: I don't know whether he ever read Einstein's paper. In fact, he never cited Einstein in connection with relativity (also Einstein ignored Poincaré's relativity contributions)... More on that topic is written by Darrigol:

http://www.journals.uchicago.edu/doi/full/10.1086/430652

Regards,

 

[harrylin]

[..]Why would a detection of the 1-way speed of light not be useful in distinguishing which theory possesses the correct foundation?
GrayGhost

Perhaps my reply was ambiguous... it's really explained (to first order) in the paper that I referred to, at the place that I referred to. Here it is again:
http://en.wikisource.org/wiki/The_Measure_of_Time - especially in XII and XIII.

Harald

 

[Histspec]

There must be a misunderstanding here: Lorentz's ether corresponds to an unpreferred inertial frame. I did elaborate on that issue (and I won't again, as it's not the topic).

Of course it's the topic. Lorentz himself used (for good reasons) the expression "preferred", in so far as clocks at rest in this aether indicate the "true" time and an "absolute" simultaneity (see the numerous quotes above, where Lorentz used exactly this terminology). Here is another quote by Lorentz (from 1909), where he also elaborated on the conceptual differences between LET and SR: pp. 229-230, http://www.archive.org/details/electronstheory00lorerich

I cannot speak here of the many highly interesting applications which Einstein has made of this principle. His results concerning electromagnetic and optical phenomena [..] agree in the main with those which we have obtained in the preceding pages, the chief difference being that Einstein simply postulates what we have deduced, with some difficulty and not altogether satisfactorily, from the fundamental equations of the electromagnetic field. By doing so, he may certainly take credit for making us see in the negative result of experiments like those of Michelson, Rayleigh and Brace, not a fortuitous compensation of opposing effects, but the manifestation of a general and fundamental principle.
Yet, I think, something may also be claimed in favour of the form in which I have presented the theory. I cannot but regard the ether, which can be the seat of an electromagnetic field with its energy and its vibrations, as endowed with a certain degree of substantiality, however different it may be from all ordinary matter. In this line of thought, it seems natural not to assume at starting that it can never make any difference whether a body moves through the ether or not, and to measure distances and lengths of time by means of rods and clocks having a fixed position relatively to the ether.
It would be unjust not to add that, besides the fascinating boldness of its starting point, Einstein's theory has another marked advantage over mine. Whereas I have not been able to obtain for the equations referred to moving axes exactly the same form as for those which apply to a stationary system, Einstein has accomplished this by means of a system of new variables slightly different from those which I have introduced. I have not availed myself of his substitutions, only because the formulae are rather complicated and look somewhat artificial, unless one deduces them from the principle of relativity itself.

You also write:

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".

Lorentz clearly said, that "true" and "local time" are not equally valid. And this was one of the reasons that he didn't "proceed more systematically". So it's not simply an "error" - it's a conceptual issue that hindered Lorentz to achieve complete Lorentz covariance. Here again the quote: http://en.wikisource.org/wiki/Two_Papers_of_Henri_Poincar%C3%A9_on_Mathematical_Physics

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'.

Do you still (like the generous Poincaré) want to downplay this issue?

Generous perhaps, but basically correct since the Lorentz transformations follow directly from Lorentz-1904.

According to this argument, Joseph Larmor would be the inventor of SR, who already in 1897 and 1900 had the complete transformation. Now, the reason why neither Larmor nor Lorentz is credited with relativity, simply lies in the fact, that they didn't possesses the correct interpretation and thus were unable to derive all possible consequences. For example, Larmor only restricted the application of the transformation to second order effects, neglecting all others. And for Lorentz, t and t' were "essentially different", which (as explained by himself) hindered him to achieve full Lorentz covariance.

And with the "physical meaning" of time dilation I had his 1899 paper in mind:
- http://en.wikisource.org/wiki/Simpl...rical_and_Optical_Phenomena_in_Moving_Systems
A mere calculation aid cannot affect such a physical vibration time.

You have to explain this to Lorentz, not to me. Look, the problem is that we have to be careful, when we speak about "physical" time when referring to Lorentz's application of this time variable, since Lorentz himself said in 1909, 1913, 1914, 1927 etc.., that time t' was only a mathematical artifice, which includes also the "modified" local time (including time dilation) from 1899 and 1904...

Thus I'll abstain from further commenting on aspects that are not perfectly on topic.

The topic's title is "Did Lorentz or Einstein theoretically derive special relativity?". All of the quotes I brought show, that Lorentz did not regard himself as having derived SR. And this is in agreement with the modern interpretation by most reputable Historians of Science (Holton, Pais, Miller, Stachel, Janssen, etc.) Off-topic are your references to Einstein's non-technical aether papers and lectures, which were ignored in any physics-textbooks in the last 70 years, while his initial judgments from 1905-1909 are still valid and accepted.

Regards,