View source for Talk:Lorentz ether theory/Archive 1

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== Well phrased ==

I just read this article to see what needed to be corrected, and to my surprise I saw little to correct, and it's mostly well phrased and presented. All that without any discussions! Congratulations for such an accurate and balanced presentation. [[User:Harald88|Harald88]] 21:59, 5 January 2006 (UTC)


I agree. [[User:Martin Hogbin|Martin Hogbin]] 12:20, 15 May 2006 (UTC)

: But now not anymore, the intro has become inaccurate. I partly revert. [[User:Harald88|Harald88]] 11:18, 7 August 2007 (UTC)

== Expansion ==

Well, I've expanded the article in accordance to the German article.--[[User:D.H|D.H]] 17:21, 6 August 2007 (UTC)

== strange sentence, please clarify ==

At the bottom of the article I came across the following sentence:

"Modern measurements empirically discredit ether theories in the massless (electromagnetic) sector."


It's not clear to me what is meant with that. In any case, Lorentz's version of SRT as well as Einstein's version of GRT (which includes SRT) imply according to them some kind of ether; and in harmony with those facts, the article states that it's a matter of taste. Thus something is obviously wrong with that sentence. Please correct it. [[User:Harald88|Harald88]] 14:20, 27 September 2007 (UTC)

: The edits where made by User:68.5.189.152. It think it's about Lorentz violation models, such as the testheories of Sexl/Mansouri etc. There is some similarity to Lorentz's theory, although they are not the same. So I tried to correct the sentence. --[[User:D.H|D.H]] 07:25, 28 September 2007 (UTC)

== Irrelevant and misleading sentence ==

The article had:

"Although Einstein in 1921 used the term „gravitational ether“ in connection of general relativity, he clearly pointed out that this was no ether in the mechanical sense.
<ref>{{Citation | author=Einstein, A. | year=1920 | title=[http://www.mahag.com/rede.htm Äther und Relativitätstheorie] | place=Berlin | publisher=Springer}}</ref>"

In fact, in the above paper, even Einstein recognized that also the ether of Lorentz was not mechanical - the suggestion above was therefore misleading to the readers. 
- http://www.mountainman.com.au/aether_0.html (better add an English reference like this one)

It may be useful however to refer to that paper, since it clarifes that with GRT Einstein came back to some kind of ether.

[[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 15:53, 18 November 2007 (UTC)

:Well, I included the following passage in the article:
:"In 1920 Einstein said that immobility is the only mechanical property of which the ether has not been deprived by Lorentz. He went on to introduce the term "gravitational ether", but contrary to Lorentz's ether the ether has no mechanical property, not even immobility:" 

{{cquote|Recapitulating, we may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether. According to the general theory of relativity space without ether is unthinkable; for in such space there not only wonld be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this ether may not be thought of as endowed with the quality characteristic of ponderable inedia, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it.}}
--[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 10:04, 19 November 2007 (UTC)

== Paragraph with suspect suggestions ==

One paragraph suggests that Lorentz betrayed Poincare after his death as follows:

"However, 1916 in his main work „The theory of electrons“ Lorentz only mentioned Einstein and Minkowski in connection with the equality of the systems, but not Poincaré. [63] [15] And in 1927 Michelson suggested that Lorentz is the discoverer of the theory of relativity, but Lorentz replied:“	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.[64]"

- Wasn't his main work „The theory of electrons“ published in '''1906'''? In that case, there is no contradiction: Lorentz had received letters by Poincare about the equality of the systems, but he could hardly make mention of private letters and there is no reason to believe that he knew of Poincare's 1905 paper.

- He may have completely forgotten about Poincare by 1928 (the year he died!), as he had worked intensely with Einstein while Poincare was long dead. However, after 1920 the "theory of relativity" usually meant the full theory (that is, '''general relativity''') and it looks suspect that Lorentz replied to a personal remark in a 1928 post-mortem(?) publication -> so, which one?

[[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 21:32, 20 November 2007 (UTC)

: It think you are aware of the dissertation "Lorentz's ether theory" by the Lorentz/Einstein expert Michel Jannsen. Well, the "suspect suggestion" was made by Jannsen, who is a reputable and well known historian of science an co-editor of Einstein's collected papers. It's true that Lorentz's book was based on lectures given in 1906, but there were '''two''' editions of Lorentz's book. The first, published in '''1909''' (three years '''after''' the lectures), the second with some '''corrections''' published in '''1916'''. So Lorentz had enough time to make corrections and to give credit to Poincare, but he didn't. Jannsen wrote in [http://www.mpiwg-berlin.mpg.de/litserv/diss/janssen_diss/Chapter3.pdf Chapter 3], p. 91.   
:<blockquote>''Poincaré had given his physical interpretation of the  x dependence  of  local  time  in,  of  all places, his contribution to the Lorentz Festschrift of 1900 (Poincaré 1900b, p. 483), and again in a lecture in St. Louis in 1904 that was published in 1905 in his book La valeur de la science (Poincaré  1904,  pp.  99–100 108 ).  Yet,  Lorentz  was  won  over  for  the  idea  only  by  Einstein. Moreover, '''he did not even mention Poincaré in this context''', whereas Lorentz is normally very careful to give credit wherever credit is due. In the '''second''' edition of The theory of electrons of '''1916''',  Lorentz  gives  credit  '''only  to  Einstein'''  in  the  following  footnote  that  is  otherwise characteristic for Lorentz’s intellectual generosity: [...] It is totally unclear to me why Lorentz did not mention Poincaré at this juncture.'' <br /> [And on p. 102 Jannsen wrote:]<br /> ''In his paper “On  the dynamics of the  electron,”  Poincaré,  working  independently  of  Einstein,  gave  an  impeccable derivation of the relativistic transformation law for charge density (Poincaré 1906, pp. 151–152; quoted and discussed in Miller 1973, pp. 251–252). '''Lorentz  does  not  refer  to  this  important contribution of Poincaré''' in this passage in The theory of electrons. In the footnote he appended to this passage in the second edition of 1916, Lorentz gives a derivation of the relation between ρ′ and ρ which is mathematically equivalent to Poincaré’s 1906 derivation, '''again without citing Poincaré'''''.</blockquote>

: On the other hand, in 1921 Lorentz published a paper, in which he gave full credit to Poincare. So Lorentz's behaviour in connection with Poincare '''after''' 1905 was very strange ;-) --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 10:27, 21 November 2007 (UTC)

:: That topic is debated between historians of science; Janssen's is just one opinion among many, and everyone can only speculate. The date of a reprint should not be put in order to suggest that it was the time of writing, that would simply be fooling the readers. In fact we don't know how long before the second edition the additional footnotes were written (don't forget WW-I!). 
:: It's of course OK to accredit debatable opinions to the persons who make them - the main rule is that Wikipedia is neutral, see [[WP:NPOV]] and [[WP:V]]. But Janssen did '''not''' insinuate that Lorentz betrayed Poincare in the above passages; instead he admitted that it was "totally unclear" to him. And "references such as "Lorentz 1928" are quite useless", since we can't verify them. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 06:43, 23 November 2007 (UTC)

It don't think that anyone says that Lorentz "betrayed" Poincare. The article only states that in 1921 Lorentz gave credit to Poincare, and in 1916 and 1928 Lorentz only gave credit to Einstein. That's all. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 07:39, 23 November 2007 (UTC)

PS: Why do you say that "references such as Lorentz 1928 are quite useless". Of course you can verify them. Look into the section [[Lorentz ether theory#Bibliography]], there you find this online available reference:
*{{Citation | author=Lorentz, H.A. | year=1928 | title=[http://adsabs.harvard.edu/abs/1928ApJ....68..341M Conference on the Michelson-Morley Experiment] |journal=The Astrophysical Journal | volume=68 | pages =345-351}} 
--[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 09:15, 23 November 2007 (UTC)

: The section indeed makes such unfounded claims and it certainly is very suggestive. Again:
: - It's essential to distinguish between facts and opinions about facts.
: - It's necessary to distinguish between publication dates of opinions from dates that those opinions were spoken or written down. 
: Note also that none of these papers and books were self-published. 
: We should try to improve that section in a Wikipedia way, and anyway the required changes are mostly small and/or subtle. 
: Thanks for explaining that although the reference is not in the Reference section, it can be found in "Bibliography". However, I think that that is far from optimal... 

: I now read Lorentz's comment of 1927, and unmistakenly there he meant special relativity. Apparently he had completely forgotten about Poincare, or perhaps he had never understood what Poincare told him. Here's where it may be useful to cite Janssen, according to whom "Lorentz  was  won  over  for  the  idea  only  by  Einstein". 
: [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 10:24, 24 November 2007 (UTC)
: PS: The bibliography is excellent, (almost?) everything is freely accessible from internet. :-)  
: [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 11:21, 24 November 2007 (UTC)

Thanks, it took me very long to find every paper of Lorentz/Poincare which are freely accessible, and I included them in the German and the English version of this Wiki-Article. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 12:38, 24 November 2007 (UTC)

: NO thank you - accessible original references is the kind of thing that really enhances the value of Wikipedia! :-)
: I will now add Janssen's partial explanation that you gave here above. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 14:32, 24 November 2007 (UTC)

I've replace the Jannsen comment with another one, which suits better, I think. I also expanded the citations of Lorentz. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 16:18, 27 November 2007 (UTC)

== The Lead Paragraph and Some General Comments ==

The opening sentence gives several alternative names for the subject of the article, but I think it's slightly misleading, because each of those names refers to different things. For example, Lorentz's electron theory refers exclusively to electrodynamics, whereas what is today called Lorentz Ether Theory is more general and essentially includes all of physics, making it an alternative interpretation of special relativity. So I would suggest omitting the alternative names in the opening sentence, and in the body of the article I would try to clearly distinguish between Lorentz's electrodynamics and the neo-Lorentzian interpretation of special relativity called Lorentz Ether Theory. It would also be worth mentioning that it's unclear whether Lorentz himself ever fully embraced what we today call Lorentz Ether theory.

Another incidental comment - the article notes that Lorentz's ether was perfectly stationary, but then talks about "vibrations" of the ether. Those two concepts are mutually exclusive. Lorentz addressed this specifically, and said his preferred conception was that the ether really is perfectly immobile, and the "oscillations" of the electric and magnetic fields are just changes in state, not spatial vibrations.

I think there may be quite a bit of overlap between the "Priority" section of this article and certain other articles in Wikipedia (for example, on Priority Issues in Relativity). Since this article is about Lorentz Ether Theory, the priority it should be discussing is related to that theory, not special relativity. The article seems somewhat confused as to its actual subject, which I supposed is understandable considering the close relationship between LET and SR. 

I'd also mention that there is a vast literature on this subject, in which all the available material is examined and evaluated by recognized scholars. Almost none of that material is mentioned in this article.  See for example Miller, Torreti, Zahar, Earman, etc. Citing those reputable sources would avoid turning this article into a "novel narrative". [[User:SJC1|SJC1]] ([[User talk:SJC1|talk]]) 17:52, 24 November 2007 (UTC)

:: I just read here above or directly in Janssen (I forgot) that Ehrenfest had used the term "Lorentz ether theory", in contrast with "Einstein's non-ether theory" or something along those lines. Probably such an early use of the term should be cited.
:: I agree that a distinction must be made between Lorentz's Electrodynamics theory (until 1904) and the New Mechanics from 1904.
:: Concerning the opinions of the authors, they are themselves the most reliable source for their own opinions. Secondary sources are required for answering ambiguities as well as for backing up the "narrative" as you put it - and the narrative is indeed that as found in such secondary sources. Thus I added one useful assertion by Janssen who BTW also discusses Miller etc. 
:: More comments may be useful, but then, I had a similar thought about the priority section: much of that seems to more belong in Priority Issues in Relativity, while about the theoretical development of Lorentz and Poincare for what here is called "LET" there doesn't seem to be any issue at all. The only issue is the misrepresentation of Poincare as being subject to a "LET" interpretation, but I think that the article is sufficiently clear about it. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 10:41, 25 November 2007 (UTC)

:Thanks for your comments. I personally prefer the interpretation of Darrigol, Galison, Jannsen etc.. But if you want to introduce some stuff of Zahar or Miller, it would be good for the balance of the article. Fell free to make some changes by yourself.

:: I'd also mention Holton and Stachel.[[User:SJC1|SJC1]] ([[User talk:SJC1|talk]]) 09:50, 25 November 2007 (UTC)

:I'm not sure if Lorentz's theory refers exclusively to electrodynamics. Ok, this was true in the beginning, but it was pointed out by Abraham in 1904 that Lorentz's electron model is not compatible with the electromagnetic worldview. Therefore Poincare was forced to introduce his non-electrical aether-stresses. Poincare also clearly pointed out that the relativity principle is valid for '''all''' forces, not only the electromagnetic ones.

:: That's my point, i.e., it eventually had to be expanded to include non-electrical effects, and ultimately ALL forces, including gravity, by which time the name "Lorentz Electrodynamics" and "Lorentz Electron Theory" are not really very appropriate any more. That's why I suggest not listing all those names as if they were synonymous. And note that even as late as 1909 Lorentz acknowledges that 

:::<i>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 new variables slightly different from those which I have introduced. I have not availed myself of his substitutions, only because the formula are rather complicated and look somewhat artificial unless one deduces them from the principle of relativity itself.</i>

::  So, historically, Lorentz reach a fully relativistic theory only after recognizing how Einstein did it with the principle of relativity, which he then outlined in Note 72 in the later edition. (Granted, Poincare did much the same thing, but only formally, and without fully recognizing the consequences.) Also, many of Lorentz's later writings make it clear that he never really bought into the fully relativistic model, even though he understood it and appreciated it.[[User:SJC1|SJC1]] ([[User talk:SJC1|talk]]) 09:50, 25 November 2007 (UTC)

::: You are making debatable and in fact debated arguments here (by chance, I also disagree with some of your claims). The only option is to cite opinions and to discuss what citation to include where. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 10:41, 25 November 2007 (UTC)

:::: It is a well-established fact, acknowledged by all the individuals themselves (Poincare, Lorentz, Einstein) as well as by all scholars, that Lorentz's 1904 was not fully relativistic (see his charge current expression). This is what Lorentz was referring to in the quotation from his 1909 book which you read above, where he specifically says this. It was corrected by both Poincare and Einstein, but only by invoking the principle of relativity itself. As Lorentz said, the formula look rather artificial unless one deduces them from the principle of relativity itself, which is precisely what both Einstein and Poincare did. And as late as 1909 Lorentz still had not assimilated this into his theory - although Bucherer's results disproving Kaufmann's claims went a long way toward getting Lorentz to adopt the fully relativistic (or else "artificial looking") version of the theory. It's certainly true that people debate things like this... but no knowledgeable and qualified people debate things like this. The non-fully-relativistic aspects of Lorentz's 1904 are not opinion, they are as objectively factual as any fact can be. Hopefully this article can be based on facts as well as the informed opinions of scholars (identified as such). [[User:SJC1|SJC1]] ([[User talk:SJC1|talk]]) 18:54, 26 November 2007 (UTC)

:It's true, the priority section is problematic, but it's hard to write a passage named "LET and SR" without mentioning the prioritiy issue between Lorentz, Poincare and Einstein.  --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 07:41, 25 November 2007 (UTC)

:: It seems the several Wikipedia articles contain sections named "LET and SR" or some variation of that, each presenting another opportunity for someone else to give their preferred interpretation. I guess that's okay, it just results in a lot of overlap and redundancy. [[User:SJC1|SJC1]] ([[User talk:SJC1|talk]]) 09:50, 25 November 2007 (UTC)

::: Indeed, as the differences concern approach and metaphysics, overlap and imprecisions are almost unavoidable. 
::: I now modified the intro; I left the term New Mechanics (which encompasses the different approaches and interpretations) out of the intro since it is not neccessary there and it is self-evident where it is quoted. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 10:55, 25 November 2007 (UTC)

I have access to two early reviews of Lorentz's 1904 paper, which can be used to sketch in a ñut shell how the new theory was understood upon reception. Perhaps the lead section is a good place to add one or two key phrases from these sources (Comptes Rendus and Annalen der Physik, both 1905). [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 11:25, 25 November 2007 (UTC)

: Both Poincare and Einstein showed in June 1905 that the statement which you attribute to Langegin in May 1905 was in error. Of course, it's possible that Langevin meant only OPTICAL experiments, but the statement as you reported it is simply wrong, as detailed later in the article, so the statement certainly doesn't belong as the ultimate statement at the end of the article lead paragraph. If you want to document each mis-statement made by Langevin (and/or each misinterpretation of your own), that should be done elsewhere. [[User:SJC1|SJC1]] ([[User talk:SJC1|talk]]) 15:27, 29 November 2007 (UTC)

:: I don't "attribute" a statement to Langevin: instread I '''cited''' it. Please don't misstate matters.  And if you want to cite arguments that Poincaré and Einstein "showed that Langevin's statement" was in error, please do so. In fact, Janssen explains that Poincaré was even mistaken when he thought to "correct" a few small errors of Lorentz; thus in the end, Langevin was spot-on wit his analysis. I have not seen "detailed elsewhere in the article" that Langevin was wrong, nor have I seen such an admission by Lorentz himself. To the contrary,the article points out that also Poincaré explained that "Lorentz tried to complete and modify his hypothesis in order to harmonize it with the postulate of the complete impossibility of the determination of an absolute movement".
Thus I reinsert his assessment and include a remark of the general purpose of Lorentz, as explained by Lorentz and also attested by Langevin and Poincaré. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 22:36, 29 November 2007 (UTC)

The leading paragraph only mentions "length contraction" and the MM-experiment. But I think mentioning the Lorentz transformation (which includes '''both''' "length contration" and "local time") is more important for that theory, and therefore I replaced the section 
<blockquote>According to Lorentz ether theory, light is transmitted through a light medium in which the motion of objects do not cause dragging effects, but do cause objects to contract in their direction of motion (Fitzgerald-Lorentz contraction). This was used as an explanation of why the Michelson-Morley experiment failed to detect an aether drag effect.</blockquote>
and inserted that one
<blockquote>According to Lorentz ether theory, light is transmitted through a light medium in which the motion of objects do not cause dragging effects, because inertial reference frames are connected by the Lorentz transformation. This was used as an explanation of why all experiments failed to detect an aether drag effect.</blockquote>
--[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 16:10, 29 November 2007 (UTC)

PS:I agree that the Langevin citation does no belong in the leading section. The "assessment" section might be a better place, if one insists in including that assessment. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 16:16, 29 November 2007 (UTC)

: OK I put it there. He was one of the few people who was up-to-date with the theory almost from the start, and he was probably the first "notable" person to write a review about the theory. 
: But I have a problem with your new addition in the lead section: it sounds as if it confuses the Lorentz ether with a Stokes aether! In the Lorentz aether there can be ''no'' drag by objects but there ''is'' a sort of drag of light by matter, the [[Fizeau]] drag effect. The Lorentz transformation (mathematics) did not explain the absence of drag (physics); instead, in his theory the stationary aether explained the existence of inertial frames as well as the Lorentz transformation. 
: Regards, [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 23:29, 29 November 2007 (UTC)

OK, I changed the lead again ;-).<br />
BTW: Lorentz himself admitted, that he wasn't able to reach complete invariance of the equations in 1904.  And Poincare only said, that "Lorentz '''tried''' to complete and modify his hypothesis". But it was actually '''done''' by Poincare and Einstein in 1905. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 07:54, 30 November 2007 (UTC)

: Yes, sure. As I hinted at here below, Janssen and others have explained that that did '''not''' mean that Lorentz made some kind of '''mistake''' - he simply did not write down the invariant forms that Poincare wrote down, and which demonstrate that the theory perfectly fulfills the PoR. THat was not clear to me in the past, and it obviously was not clear to SJC1 when he claimed that Langevin had it wrong! [[User:Harald88|Harald88]] 01:43, 1 December 2007 (UTC)

== Assessments: for balance, also negative assessments ==

I have the impression that especially in later times, the assessments about "LET" turned more negative and certainly nowadays many people think that it is outdated or so. For proper balance in views, it would be great if someone could find and cite one or two of such negative views. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 23:26, 29 November 2007 (UTC)
: A first suggestion by myself: cite Janssen's opinion that SRT is preferable.

: On a side note: it will certainly be useful to explain in a separate section the concept of corresponding states, and the misunderstandigs about it that started with Poincaré. This is well explained in Janssen chapter 3 "common misconceptions" (near the end).
: In fact, an article of this length should not miss such an essential point. 
: [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 07:30, 30 November 2007 (UTC)

Maybe too much of Jannsen is not good for the article, but I will try to insert some other assessments. --[[User:D.H|D.H]] 15:58, 30 November 2007 (UTC)

: Yes, that thought also came up in my mind. However, Janssen is probably the most notable modern day "LET" expert and a respected source at that; moreover, he gives an overview of commentaries of others. :-)
[[User:Harald88|Harald88]] 13:27, 1 December 2007 (UTC) (I had forgotten to sign that)

== Comments on the Latest Edits to Lead Paragraph ==

The latest edits to the lead paragraph, consisting of:

:The purpose of his theory was to explain why no experiments had been able to detect any motion relative to the aether. According to Lorentz ether theory, light is transmitted through a light medium in which the motion of objects do not cause dragging effects, because inertial reference frames are connected by the Lorentz transformation. This was used as an explanation of why all experiments failed to detect an aether drag effect.

need improvement in my opinion. For example, the sentence

:"The purpose of Lorentz Ether Theory was to explain why no experiments had been able to detect any motion relative to the ether."

is messed up in two ways. First, Lorentz's purpose was to give a satisfactory account of electrodynamics, which includes but is not limited to just the one specific fact mentioned. So it's silly to list this as "the" purpose of the theory. In fact, Lorentz began working on the theory before that fact was known or even suspected. Also, the sentence once again confuses the subject of the article. You need to decide if the article is about Lorentz's theory in the historical sense, or about the modern neo-Lorentzian theory. The above sentence is presented right after following the development through Einstein and Minkowski, so at this point is "the theory" really Lorentz Ether Theory or is it special relativity? The article concludes by saying the two are empirically indistinguishable, so why isn't this stated in the lead paragraph? The modern Lorentz theory consists of special relativity with the added metaphysical assertion that one of the reference frames is "true"? On the other hand, if the article is about the historical Lorentz theory (at various times) this is not true.

This leads to another big problem with the latest edits. The discussion of inertial reference frames being connected by Lorentz transformations leads to confusions, again because this depends on whether you are talking about Lorentz's interpretation of his theory, or subsequent modern re-interpretations of his theory. Remember, according to Lorentz, inertial reference frames are related by Galilean transformations, and we can speak of absolute simultaneity without further specification, etc., whereas the "effective" coordinates referred to in the theory of corresponding states are related by Lorentz transformations. He later understood (from Einstein) that it's possible to regard the effective coordinates as actual inertial coordinates, but he never fully embraced this view. Poincare came closer, but he never really fully adopted this view either. On the other hand, it's possible for a modern neo-Lorentzian to adopt this view... although this is perilously close to special relativity. So again it all depends on precisely what you are trying to describe in this article.  It seems to jump all over the place.

I'm tempted to suggest that the article should be called something like "The Origins of Special Relativity", or maybe "An Essay on the Historical Development of the theories of electrodynamics, from the late 19th century to today". But that isn't very encyclopedic. Maybe it should be "A Survey of the Literature commenting on the development of Special Relativity and Related Theories". I don't know. The article is problematic. I also suggest you guard against just making it a Survey of Jansenn's views. He should only be about 5% of the views expressed. You should refer to at least 20 equally or more distinguished scholars on this subject (unless you want to entitle the article "Janssen's Views of History").[[User:SJC1|SJC1]] ([[User talk:SJC1|talk]]) 07:55, 30 November 2007 (UTC)

:: The problem is indeed in the term "Lorentz ether theory"; it was perhaps only once used (by Ehrenfest) to indicate the difference between Lorentz's ether relativity and Einstein's non-ether relativity (I adviced and still advice to include that citation, as found in Janssen). I any case, that is also what is ''usually'' meant in modern discusions - it does not just stand for an ether idea, and it should '''not''' be confused with his older, more limited theory of electrons. Both "LET" and "SRT" mean different things for different people, and "LET" is probably the least well defined.
:: Also, your assertion that "if the article is about the historical Lorentz theory (at various times) this is not true", is erroneous - as Janssen and others explained. Your reaction on those explantions was that Langevin (and, consequently, also Janssen) was wrong, but that doesn't do. The only thing you can do is propose a citation of that point of view, which then must be accompanied by the counter opinion with its explanation. That is what I brought here above, about the "confusions" related to the corresponding states. 
:: Apart of that, your assessment that there are 20 equally or more distinguished experts about Lorentz's theory is big news to me! Please give references to some others. [[User:Harald88|Harald88]] 02:08, 1 December 2007 (UTC)

:Thanks for the analysis. It's true that the historical theory of Lorentz and Poincare must be distingueshed from modern neo-lorentzian theory (although the difference is not very great). Therefore I splitted the article in an historical section, and a recent activity section, and I plan to introduce the testtheory of Mansouri/Sexl in some detail. <br />
:However, it must be said that the difference in the historical theory of Lorentz and modern derivates of LET is not as great as you suggest. For example, look what Lorentz said in 1913: ''In all frames of reference this one has to be preferred, in which the ether is at rest. Clocks in this frame are showing the „real“ time and '''simultaneity is not relative'''. However, if the correctness of the relativity principle is accepted, it is impossible to find this system by experiment. He went on by saying, that there is little difference between the negation of a preferred reference frame, as in the theory of Einstein and Minkowski, to his own model. So it is a matter of taste which theory one prefers.''<br />
:Well that's a very good definition of a modern, neo-lorentzian interpretation of SR. For example, Mansouri/Sexl wrote (General Relativity and Gravitation, Vol.  8, No. 7 (1977),  pp. 497-513):
:<blockquote>p.500: In this theory measuring rods show the standard Fitzgerald-Lorentz contraction and clocks the standard time dilatation when moving relative to  the ether. Such a theory would have been the logical consequence of the  development '''along the lines of Lorentz-Larmor-Poincaré'''. That the actual development went along different lines was  due to the fact that  "local time" was introduced '''at the early stage''' in considering the covariance of the Maxwell equations. <br /> p. 512:  Thus  the  much  debated  question  [29,  30]  concerning  the  empirical equivalence  of special relativity and  an ether  theory taking into  account  time  dilatation and length  contraction but  maintaining '''absolute  simultaneity''' can be  answered  affirmatively.</blockquote> 
:Of course, Mansouri/Sexl preferred SRT over LET, but the interpretation of the ether is nearly exactly the same as Lorentz's. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 09:01, 30 November 2007 (UTC)

::I changed the introduction to emphasize the difference between the historical theories and modern neo-lorentzian models. And a description of the test theory of Mansouri/Sexl in the "Recent activity" section is also created. --[[User:D.H|D.H]] 16:01, 30 November 2007 (UTC)

::: Two points:
::: 1. Why did you put "neo-Lorentzian" instead of "Lorentzian"? In his textbook, Lorentz himself presented his theory as an interpretation of special relativity; should Lorentz be called "neo-Lorentzian"? :-)) 
::: 2. You now brought up another discussion item in the lead: "seems to be only coincidental". Logically that should be developed in the article. If you indeed intend to include the discussion about that assessment, I can provide a citation of Ives who showed that the PoR necessarily follows from the postulate of a stationary ether together with the conservation laws. 
::: Regards, [[User:Harald88|Harald88]] 02:24, 1 December 2007 (UTC)

As I said, the difference between the historical and modern versions of LET is not so great. However, Lorentz and Poincare developed the theory by trying to combine the Maxwell-equations with the relativity principle (without further explanation), but in modern versions (Grünbaum, Mansouri/Sexl etc.), a stationary ether (and absolute simultaneiity) is combined with the effects of length contraction and time dilation (also without explanation). Therefore, Minkowski called length contraction within Lorentz's model ironically as a "gift from heaven", and also Einstein critisized the ad-hoc character of Lorentz's hypothesis. <br />
PS: Mayby you can insert some information on Ives in the "Recent activity /Neo-lorentzian interpretations" section. As far as I know, Ives defined velocity dependent mass, length contraction and time dilation as absolute effects in a stationary ether - no great difference to the Mansouri/Sexl. His neo-lorentzian interpretation is also based on energy and momentum conservation.  --[[User:D.H|D.H]] 07:56, 1 December 2007 (UTC)

: Fine, but it is definitely misleading and confusing to call Lorentz's opinion "neo-Lorentzian". 
: I'll try to add something to "neo(?) Lorentzian interpretations" later, when I have more time.
: Regards, [[User:Harald88|Harald88]] 13:25, 1 December 2007 (UTC)

I haven't invented the term "neo-lorentzian" ;-). But it's commonly used by many people - for example look at this article: [http://philsci-archive.pitt.edu/archive/00000525/ Presentism and Relativity]. Well, some people called themselves "Lorentzians", and others "Neo-lorentzians". But those are only words, which isn't very important, I think. --[[User:D.H|D.H]] 14:48, 1 December 2007 (UTC)

== Langevin again ==

The statement of Langevin in his [http://gallica.bnf.fr/ark:/12148/bpt6k30949/f1243.table 1905-paper], that Lorentz arrived at "the physical impossibility to demonstrate the translational motion of the earth", is not correct, as pointed out by Poincare and Lorentz himself. However, I put the citation into the Lorentztransformation paragraph and wrote: 
<blockquote>One of the first assessments of Lorentz's paper was by Paul Langevin in May 1905. According to him, this extension of the electron theories of Lorentz and Larmor led to "the physical impossibility to demonstrate the translational motion of the earth". [23] However, '''as shown by Poincaré''' on 5 June 1905, '''Lorentz didn't succeeded completely''' to show that the laws of electrodynamics were form-invariant.</blockquote>
I don't know if his [http://diglib.cib.unibo.it/diglib.php?inv=7&int_ptnum=10&term_ptnum=39&format=jpg 1911 paper] should be mentioned in the article, although it's interesting, because it contains the first formulation of the twin paradox. --[[User:D.H|D.H]] 07:32, 4 December 2007 (UTC)

: NO, it is wrong to state that Langevin's assessment was not correct, as both Lorentz himself stated and Janssen and others that he referred to explained that Lorentz's theory '''did''' arrive at that - and as pointed out here above by me in my comments of last week! Please study the last part of Janssen and don't put words in Lorentz's mouth that he didn't say. According to them, Lorentz simply did not succeed in '''showing''' that the laws of electrodynamics were form-invariant - and in fact, it wasn't even clear to himself at that time. THus your rephrasing is correct but the emphasis is wrong, as well as the removal from assessments.

: Langevin's paper was a strong support for LET (IMHO, one of the strongest arguments in its favour ever written) - that it also contained what would become the "Twin paradox" for those who rejected LET is of secondary importance for this article.

[[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 23:16, 9 December 2007 (UTC)

Not every scholar has the same opinoun as Jannsen. Lorentz clearly wrote in 1921: 
<blockquote>I was not able to achieve total invariance of the equations; '''my formulae remained cluttered''' up with excess terms, '''that should have vanished'''.  These terms were too small to inﬂuence phenomena noticeably, and by this  fact  I  could  explain  their  independence  of  the Earth’s motion, revealed by observations, but I did not establish the relativity principle as a rigorous and universal truth. On the contrary, Poincaté achieved total invariance of the equations of electrodynamics and formulated the relativity postulate — a term ﬁrst introduced by him . . . I may add that, while thus correcting '''the defects of my work''', he never reproached me for them.</blockquote>

Lorentz used the words "defects of my work". And BTW: I think that Jannsen was unaware of the 1921-paper of Lorentz.--[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 07:46, 10 December 2007 (UTC)

: Unpublished personal material is not allowable for Wikipedia, and "to have '''cluttered''' formula's isn't an error. However, I find the admission by Lorentz of "excess terms, that '''should''' have vanished" and "'''too small''' to inﬂuence phenomena noticeably" rather convincing evidence that he indeed agreed with Poincare.
: Still, one or two errors don't make a theory wrong; while if it would be so, then Einstein's 1905 paper should be similarly rejected since that one contains big errors such as for relativistic mass. Similarly, Poincaré himself stated in the same paper in which he perfected Lorentz's paper:
: "The essential point, established by Lorentz, is that the electromagnetic field equations are not altered by a certain transformation, which I will call by the name of Lorentz". 
: Thus it remains a judgment call, and a matter of weighing with the same measures (=NPOV).
: As Lorentz and Poincare are cited, adding the assessment of Langevin in its proper place will help the readers to understand that "LET" vintage 1904 already contained the basic elements of relativity theory and that this had been mentioned in the French (CR) and German (Beiblätter) literature before Poincare and Einstein came with improvements. 

: In addition, it should also be made clear that already Poincare 1904 refers to Lorentz 1904, eventhough it wasn't a review of Lorentz's paper but some strong and inspiring preliminary comments based on it.

: [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 23:53, 10 December 2007 (UTC)

== another suspect uncited statement ==

"So Einstein thought it was necessary to replace Lorentz's theory by another one".

I think that that is wrong and claimed by nobody, so I added a tag. As far as I know, Einstein always claimed innocence of knowledge of Lorentz's 1904 paper at the time of his 1905 paper and he also suggested not to know of Poincaré's 1904 and 1905 papers. Moreover, in 1907 he even referred to '''both''' his paper of 1905 '''and''' that of Lorentz of 1904 as describing the basics of the new theory. 

Note also that it's biased to present negative opinions about the length contraction hypothesis ("ad hoc") and not the positive counter opinion of Lorentz ("not ad hoc").

[[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 23:02, 9 December 2007 (UTC)

: It's not uncited. Einstein himself said this, look at Ref. 66 (1907), where he wrote: "Es hatte daher den Anschein, als ob die Lorentzschen Theorie wieder verlassen und durch eine Theorie ersetzt werden müsse, deren Grundlagen dem Relativitätsprinzip entsprechen".<br />
:Unfortunately, in the next weeks I have not time to make edits on this page. Merry Christmas to you --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 07:39, 10 December 2007 (UTC)

:: 1. It was uncited in the article. And if you add that citation, it is misleading: "die Lorentzschen Theorie" points in that article to Lorentzian Electrodynamics ("H. A. Lorentzsche Elektrodynamik") and not to Relativity. Both Lorentz and Einstein agreed that Lorentzian Electrodynamics needed to be replaced by a new theory. Thus that sentence must be rephrased accordingly. 

:: Note: I now notice that Einstein did not emphasize the difference between Lorentz 1904 ("LET") and Lorentz 1895 ("Lorentzian Electrodynamics"). It's however clear when taking into acount that he discusses Kaufmann's paper which also cites both Lorentz 1904 and Einstein 1905, and by adding emphasis: 

::"Im folgenden ist nun der Versuch gemacht, die '''Arbeiten''' zu ein em Ganzen '''zusammen zu fassen''', welche bisher '''aus der Vereinigung''' von H. A. Lorentzscher Theorie und Relativitätsprinzip '''hervorgegangen''' sind. In den ersten beiden Teilen der Arbeit sind die kinematische Grundlagen sowie deren Anwendung auf die Grundgleichungen der Maxwell-Lorentzschen Theorie behandelt; dabei hielt ich mich an '''Arbeiten von Lorentz (1904) und Einstein (1905)'''."

:: That example by Einstein was followed in the first publication of the collection of papers "Lorentz et al, ''The Principle of Relativity''".

:: 2. The "ad hoc" in that article similarly referrs to length contraction in Lorentzian Electrodynamics (1895); apparently Einstein cites there the argument that Poincare made against that older theory, and to which the New Mechanics / Special Relativity was an an answer. 

:: 4. For neutrality Lorentz's opinion of the non-ad-hoc nature of length contraction must be cited as well.

:: 3. Have a nice vacation!

:: [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 23:06, 10 December 2007 (UTC)

== Admitted bias by commentators ==

It will be useful to express the admitted or obvious bias of the cited secondary sources. For example Darigol, despite the fact that he may well be one of the least biased commentators, admits to have an "Einsteinian" philosophical bias which indeed affects some of his commentaries in an obvious manner. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 23:24, 9 December 2007 (UTC)

== Editorial: Shift to SRT, Assessments and Priority ==

- It appeared as if Assessments of LET was instead about assessment of the shift to SRT. What matters most for an article on a topic (LET) is assessment about that topic and not about the shift to a variant of it. Thus I made the assessment independent of the Shift to SRT topic.

- As discussed before, priority issues are discussed elsewhere. Worse, by splitting assessments up into assessments and a sub topic about priority issues, much that also belongs in the assessments  main is now under priority. Thus it will be better to move everything that belongs under assessments out of priority, and to keep priority as short as possible and with a link to the corresponding article.

- Assessments that arguably are not about LET don't belong there, in particular not if no secondary source makes that claim.

[[Special:Contributions/83.76.119.112|83.76.119.112]] ([[User talk:83.76.119.112|talk]]) 07:49, 11 December 2007 (UTC)


== Ives's Misunderstanding ==

Harald says "To highlight the value of the LET interpretation [Ives] published a paper that describes how the Lorentz transformations necessarily follow from classical space and time concepts in combination with the laws of Maxwell and the conservation laws." This is simply wrong, and it is well known to be wrong, and the wrongness of it can be verified in innumerable reputable sources. Only anti-relativity cranks fail to understand Ives's mistake, which isn't surprising, since it's the same mistake they themselves have based their lives upon. The mistake (for the benefit of any non-crank who may read this) is that the Lorentz transformations of space and time do NOT follow from the laws of electromagnetism, because there are other forces of nature (gravity and the strong and weak nuclear forces) that do not satisfy the laws of electromagnetism, and yet are Lorentz covariant. Obviously the Lorentz covariance of non-electromagnetic forces does not "necessarily follow" from the laws of electromagnetism. Furthermore, even electromagnetism is now known not to be governed by Maxwell's equations, a fact which was already apparent in 1900 with Plank and the ultra-violet catastrophe, and even more clear in 1905 with Einstein's quantum photon, and utterly clear today (in 2007) with the well established quantum electrodynamics. Hence, the premise of Maxwell's equations was incorrect, and even if it had been correct, it was clearly insufficient to serve as the basis for space and time transformations. For Lorentz the transformed t and x were derived only for Maxwell's equations. For everything else (e.g., mechanical inertia) Lorentz and Poincare simple and explicitly ASSUMED Lorentz covariance. They finally realized that this assumption (relativity) was necessary and unavoidable to fully account for the inability to detect absolute motion. But, having labored for decades only to arrive at the necessity of this assumption, they were surprised to learn that it was also fully sufficient. All the other deductive labor prior to the assumption of relativity was superfluous, because once you assume relativity, all the rest follows. In other words, the idea espoused by Ives's and his ilk is totally false, and is well-known to be false. It would be helpful if editors of this article at least educate themselves to the point where they understand this. [[User:SJC1|SJC1]] ([[User talk:SJC1|talk]]) 22:45, 11 December 2007 (UTC)

: There are many assertions in the above emotional discourse, even the suggestion that a famous scientist and the reviewers of the journal in which he published were "cranks". In any case, the above claim that my abovementioned paraphrase about Ives is "simply wrong" was not supported by any reference, and the arguments dealt with a truncated version of that sentence: nowhere was it claimed that the "Lorentz transformations follow from the laws of electromagnetism". And perhaps SJC1 meant that I should have written "according to Ives"? That is easily fixed! :)
: Imperfections are no excuse for the deletion of a reference. Thus I reinsert that paragraph. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 17:53, 29 March 2008 (UTC)

== Expansion -2 ==

I've expanded the sections "Principles and conventions", "The shift to relativity" and the "Bibliography". Some of the assessments of Poincaré and Lorentz were moved into the sections "Principles and conventions" and "The shift to relativity". Also the section "mass-energy-equivalence" is moved into the relativity section. Some corrections in the sections Lorentz-transformation (charge density, four-dimensional space) and some minor corrections (style, references) in other sections were made.--[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 15:49, 29 December 2007 (UTC)

== Relativity priority dispute ==

I moved the priority section into the article [[Relativity priority dispute]]. There seems to be the correct place. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 17:33, 15 March 2008 (UTC)

== original research deleted ==

I made the description of Ives' neo-Lorentzian theory more to-the-point by removing irrelevant (and rather misleading) comments about his opinion on other interpetations - that section is about neo-Lorentzian interpretations and not about other ideas or claims by Ives or about Einstein's interpretation. I also deleted new original research that was phrased as follows: 

''He published a paper in which he asserted (erroneously<ref>See, for example, Lorentz, H. A., The Theory of Electrons, 1909, for a discussion of the foundations of Lorentz's ether theory.</ref>)'' .

Clearly the reviewers of Ives' paper disagreed with the abovementioned claim; and certainly Lorentz did not comment in 1909 on Ives' paper! I have read Ives' paper and I disagree with calling it a "derivation": I would call it a deduction. However, I found no errors and I know of no exisiting paper that makes such a claim - to the contrary! Other scientists such as Emmy Noether have also emphasized that everything follows from the conservation laws - and to make that clear we could add a reference to such a paper, but then again, it's not really to the point. I now found http://www.eftaylor.com/pub/symmetry.html but I haven't read it. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 17:54, 19 April 2008 (UTC)
: Note: it was only after the inception of relativity theory that the inertia of energy became well understood. That knowledge was used in Ives' derivation. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 19:18, 19 April 2008 (UTC)

== Problems with "Later Activity" Section ==

The section entitled "Later Activity" at the end of the article seems mis-labeled and out of place. It consists of just three topics, a summary of Herbert Ives' ideas, a mention of a parameterization for characterizing Non-Lorentzian theories, and a discussion of <i>breaking</i> Lorentz symmetry. The latter two are explicitly NOT taking about Lorentz ether theory, so they don't really belong in the article. The first, discussing Herbert Ives, is not really notable as "activity" on Lorentz ether theory, but only as opposition to special relativity. Ives was not a significant scientific figure, nothing he wrote was new, and articles published in the Journal of Optics do not constitute scholarly research papers in fundamental physics. In summary, I would say the entire last section should be deleted, until someone can provide some actual content pertaining to actual recent activity on Lorentz ether theory.[[User:Denveron|Denveron]] ([[User talk:Denveron|talk]]) 04:41, 4 May 2008 (UTC)
:As Robertson said, Ives theory (which included a preferred reference frame) is only a complicated form of SR and therefore it seems to be a good example of a lorentzian interpretation of SR. So why not mention it? And Mansouri/Sexl themselves say that their test theory is "along the lines of Lorentz-Larmor-Poincaré". However, I agree that the last section on symmetry is unnecessary, therefore I deleted it. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 08:46, 4 May 2008 (UTC)

== Heaviside's 1889 paper ==

In the main article, under 'Length Contraction' it says that in 1889 Heaviside derived a contraction factor for the electrostatic field of <math>\sqrt{1- v^2 / c^2}</math>. In actual fact, Heaviside begins that derivation with the electromagnetic wave equation. Hence the E field in question is the (Faraday) E field equal to (partial)dA/dt that is being propagated from a radiation source, as opposed to the electrostatic (Coulomb) E field. To me, it looks more like a Doppler shift than a contraction of the electrostatic field. It should also be remembered that Heaviside used a series expansion, and that there are extra terms in the series beyond the <math>\sqrt{1- v^2 / c^2}</math> term. And furthermore, the <math>\sqrt{1- v^2 / c^2}</math> factor is used in connection with the A vector potential and not the E vector force. Is there a secondary source that specifies that Heaviside was specifically talking about the 'electrostatic field' contracting? In the primary source, Heaviside refers to E as the 'electric force'. This sentence in the main article needs to be tidied up somewhat. [[User:David Tombe|David Tombe]] ([[User talk:David Tombe|talk]]) 01:17, 24 September 2009 (UTC)

== another wrong claim ==

The article states: "Lorentz came very near to create such a theory, where all forces between the molecules, whatever their nature may be, are affected by the Lorentz transformation"

That sentence suggests that Lorentz's new theory of 1904 does '''not''' assert that all forces between the molecules, whatever their nature may be, are affected by the Lorentz transformation. However, that is erroneous, for that is just what the new theory holds - in order to comply to the PoR!

Lorentz actually motivated this better than Einstein one year later:

" In the second place I shall suppose ''that the forces between uncharged particles, as well as those between such particles and electrons, are influenced by a translation in quite the same way as the electric forces in an electrostatic system.''
[...]
In virtue of the second hypothesis of § 8 we may therefore apply to the resulting molecular force acting on a particle, the equation (21). "

Thus several sentences need correcting. It appears to be an (unreferenced) attempt to propagate the fable that Lorentz did not account for the PoR, and that his theory was purely constructive. 
[[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 14:43, 18 June 2010 (UTC)

:The former statement "Lorentz came very near to create such a theory" only says, that Lorentz's theory does not completely fulfil the PoR, because a) of his wrong expressions for current and charge density b) he didn't showed that non-electrical forces are actually compatible with his theory c) he didn't include gravitation in his paper. This theory was created by Poincaré 1 year later... BTW: Lorentz was of course to '''some extend''' guided by the PoR - but there is absolutely no evidence, that Lorentz in fact wanted to account for the '''complete''' PoR, as it was done by Poincaré and Einstein (there are a lot of references for this interpretation, see Janssen or Rynasiewicz etc.). So Lorentz had good reason, why he always attributed the PoR to Einstein (and sometimes to Poincaré). --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 15:44, 18 June 2010 (UTC)

:: I see... then the way you put it was merely ambiguous. But for consistency you should make similar remarks in the article about SRT, as Einstein's 1905 paper also contains errors and similarly does not include gravitation. Note that in his 1904 paper, Lorentz correctly attributes the PoR to Poincare and that one does not need to show what one postulates ("supposed", "hypothesis"). [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 19:49, 20 June 2010 (UTC)

:: I suddenly notice that also the introduction is affected by the wrong presentation, since Lorentz did not claim that all forces must be electromagnetic in nature ut that all forces (incl. those between uncharged particles) must transform the same way as electric forces. I will correct this now, in view of the above citation. [[User:Harald88|Harald88]] ([[User talk:Harald88|talk]]) 14:59, 4 July 2010 (UTC)
:::Lorentz simply said that '''if''' non-em forces do exist, that they must transform the same way as electric force. But nowhere in in his 1904 paper he showed that such non-em forces are necessary, or that it is possible to include them within his theory. And your edits give the wrong impression, that Lorentz's theory  '''completely''' fulfilled the PoR - which is (you know it well) not the case. This was done by Poincaré one year later. And as I said above, there is no evidence, that Lorentz subscribed to the '''complete''' PoR of Poincaré. (See also the views of Historians like Jannssen or Rynasiewicz - and in WP we have to rely on secondary sources.) And of course the 1909 paper is important - there he corrected his mistakes from 1904. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 20:31, 4 July 2010 (UTC)

== Constancy ==

Someone states "Einstein explained that he borrowed the principle of the constancy of light from Lorentz's immobile ether" in this wiki.

Where are the references to that? 

Found two linking it to Einstein in 'Relativity priority dispute', but reading the English version of one of them http://en.wikisource.org/wiki/The_Development_of_Our_Views_on_the_Composition_and_Essence_of_Radiation, I could find no such statement? This I found though.. "This state of affairs was very unsatisfying. The only useful and fundamentally basic theory was that of Lorentz, which depended on a completely immobile ether. The Earth had to be seen as moving relative to this ether. But every experiment designed to demonstrate this ether had a negative result, so that one was driven to a very strange hypothesis to understand why such a relative motion was not detectable." which definitely isn't the same as that statement above. For a nice historical view of the definition of his ideas, look up; http://www.aip.org/history/einstein/essay-einstein-relativity.htm .. I won't even bother read the second link. Try to get your facts right please. Maxwell, anyone heard about him? And it's even worse reading that 'Relativity priority dispute' as they then actually link to something not existing, as far I can see? 

Not good.

[[Special:Contributions/83.182.199.240|83.182.199.240]] ([[User talk:83.182.199.240|talk]]) 23:53, 18 March 2012 (UTC)

:Read the 1912 paper (''Relativity and Gravitation: Reply to a Comment by M. Abraham'', translation by A. Beck in Einstein's Collected papers, vol. 4). Einstein wrote:
::'''English''' "''...it is impossible to base a theory of the transformation laws of space and time on the principle of relativity alone. As we know, this is connected with the relativity of the concepts of “simultaneity” and “shape of moving bodies.” To fill this gap, I introduced the principle of the constancy of the velocity of light, '''which I borrowed from H. A. Lorentz’s theory''' of the stationary luminiferous ether, and which, like the principle of relativity, contains a physical assumption that seemed to be justified only by the relevant experiments (experiments by Fizeau, Rowland, etc.). ''" '''German''': "''Es ist allgemein bekannt, dass auf das Relativitätsprinzip allein eine Theorie der Transformationsgesetze von Raum und Zeit nicht gegründet werden kann. Es hängt dies bekanntlich mit der Relativität der Begriffe „Gleichzeitigkeit“ und „Gestalt bewegter Körper“ zusammen. Um diese Lücke auszufüllen, führte ich das der H. A. Lorentzschen Theorie des ruhenden Lichtäthers entlehnte Prinzip der Konstanz der Lichtgeschwindigkeit ein, das ebenso wie das Relativitätsprinzip eine physikalische Voraussetzung enthält, die nur durch die einschlägigen Erfahrungen gerechtfertigt erschien (Versuche von Fizeau, Rowland usw.)''"
:Or the [[s:The_Development_of_Our_Views_on_the_Composition_and_Essence_of_Radiation|1909 paper]]:
::'''English''': "''According to Lorentz's theory, if a light beam propagates through space, it does so with a speed c in the resting frame K of the ether, independently of the state of motion of the emitting object. '''Let's call this the constancy of the speed of light principle'''.''" '''German''': "''Pflanzt sich nämlich ein Lichtstrahl im Vakuum fort, so geschieht dies nach der LORENTZschen Theorie in bezug auf ein im Äther ruhendes Koordinatensystem K stets mit der bestimmten Geschwindigkeit c, unabhängig vom Bewegungszustande des emittierenden Körpers. Wir wollen diesen Satz das Prinzip von der Konstanz der Lichtgeschwindigkeit nennen." 

:See also the link you gave (http://www.aip.org/history/einstein/essay-einstein-relativity.htm):
::''The second of Einstein's principles is based on an important consequence of Maxwell's laws of electricity, magnetism, and optics, '''as interpreted by H. A. Lorentz''' near the end of the nineteenth century.

:Note that when we speak about "Maxwell", it's not about the original Maxwell theory, it's about "Maxwell-Heaviside-Hertz" (moving aether) or "Maxwell-Lorentz" (resting aether). As Einstein said, Lorentz introduced the constancy of light speed in '''one''' frame by assuming a completely motionless aether. Einstein's great achievement was to generalize this statement to '''all''' frames by abandoning the aether and thus making the constancy of the speed of light compatible with the relativity principle. This is all well known, see the books of historians like Martinez, Stachel, Miller, etc. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 09:24, 19 March 2012 (UTC)

:: Good edits. I just made a couple of edits myself to that section, altho I have not yet filled in the Minkowski "Space and Time" reference. But I do not agree that "Lorentz introduced the constancy of light speed in one frame". Where does Lorentz say anything about "one frame"? Lorentz's purpose was to explain Michelson-Morley, and that requires the speed of light to be constant in multiple Earth frames, not just the aether frame. [[User:Schlafly|Roger]] ([[User talk:Schlafly|talk]]) 21:45, 19 March 2012 (UTC)

:::It's about what Einstein called the "fundamental assumption of Lorentz's theory" of 1895: The stationary aether. This is one frame having the properties of an inertial frame. All other frames in Lorentz's theory only appear to be inertial, due to the unexplained action of some effects such as length contraction and time dilation with respect to the aether. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 22:26, 19 March 2012 (UTC)

:::: Are you quoting Einstein? If so, where and when? I thought that Einstein would have said that the fundamental assumption of Lorentz's theory was either Maxwell's equations or the relativity principle. [[User:Schlafly|Roger]] ([[User talk:Schlafly|talk]]) 23:05, 19 March 2012 (UTC)

:::::Lorentz himself stated in the introduction of his 1895 paper that he bases his theory on (Fresnel's) immobile aether, as opposed to Stokes' moving aether. As Einstein correctly said in his 1907 paper (translation [http://hermes.ffn.ub.es/luisnavarro/nuevo_maletin/Einstein_1907_Jahrbuch.pdf by Schwartz]) about Lorentz's 1895 theory: "''That theory is founded, namely, on the assumption of a stationary immobile aether''". Then Einstein said it can explain first order effect, but was in contradiction with second order effects such as the MM experiment. Therefore Lorentz ad-hoc introduced length contraction "''as an artificial device for saving the theory''". But Lorentz's theory could be saved and brought into full agreement with the relativity principle when "local time" is replaced by "time" per se, and the new transformation equations are used. However, only the aether must be abandoned. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 08:57, 20 March 2012 (UTC)

For an overview, see [https://webspace.utexas.edu/aam829/1/m/Kinematics6.html this chapter]] from the book of Martinez. It goes into some detail. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 16:51, 20 March 2012 (UTC)

: Thanks for posting the Schwarz translation, but I do not agree with your interpretation. That Einstein quote is from a paragraph on [[Galilean invariance]]. "That theory" refers to Maxwell's equations, which Einstein goes on to say "are not so constructed that they go over into equations of the same form upon application of the above transformation equations."
: Einstein only starts discussing the Lorentz 1895 theory in the next paragraph. The paragraph after that says that the Lorentz-FitzGerald contraction was "ad hoc", and then "It appeared thus that Lorentz's theory had to be abandoned again, and replaced by a theory whose foundations agreed with the principle of relativity". He then credits that replacement theory to Lorentz 1904 and Einstein 1905.
: I read this as saying that there are 3 Lorentz theories. Lorentz-1 is Maxwell's equations, aka Maxwell-Lorentz theory, with Galilean transformations for a different velocity frame. Lorentz-2 is the Lorentz 1895 paper. Lorentz-3 is the Lorentz-1904 paper and Einstein 1905 paper. When Einstein says "Lorentz's theory had to be abandoned again", he means that Lorentz was abandoned once going from Maxwell-Lorentz to Lorentz-1895, and abandoned a second time going from Lorentz-1895 to Lorentz-1904.
: Thus I do not agree that the "fundamental assumption of Lorentz's theory" of 1895 was the stationary aether. I do not think that Lorentz or Einstein would have made such a statement. [[User:Schlafly|Roger]] ([[User talk:Schlafly|talk]]) 05:03, 21 March 2012 (UTC)
::If Lorentz' aether was not stationary what exactly is it doing? [[User:Martin Hogbin|Martin Hogbin]] ([[User talk:Martin Hogbin|talk]]) 08:55, 21 March 2012 (UTC)

:::The first theory is simply "Maxwell's theory", which was further developed by Thomson, Poynting, Heaviside and Hertz. Then we have the Maxwell-Lorentz theory of 1892/1895, which was based on Fresnel's stationary aether.  The reason why Lorentz favored Fresnel's resting aether against Stokes's aether drag model are explained at length by Lorentz in the [[s:Attempt of a Theory of Electrical and Optical Phenomena in Moving Bodies/Introduction |introduction]] of his 1895 paper. Besides the aether, the 1895 model also contained the mathematical local time, in order to avoid aether drift effects to first order in v/c. This 1895-model is what Einstein in 1907 called "Lorentz's electrodynamics". See also Einstein [[s:The_Development_of_Our_Views_on_the_Composition_and_Essence_of_Radiation|in 1909]]: ''"This contradiction was chiefly eliminated by the pioneering work of H. A. Lorentz '''in 1895'''. Lorentz showed that if the '''ether were taken to be at rest''' and did not participate at all in the motions of matter, no other hypotheses were necessary to arrive at a theory that did justice to almost all of the phenomena."'' However, Lorentz had to introduce length contraction as ad-hoc hypothesis in 1892 in order to explain MMX, and then to extend the whole 1895-model in 1904 in order to fully combine the aether concept with the relativity principle. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 09:40, 21 March 2012 (UTC)

:::: Yes, Lorentz does explain himself in that 1895 introduction. He rejects the aether drag model, and says that the aether is "at rest" as a way of saying that. He says, "It is not my intention to ... express assumptions about the nature of the aether. ... That we cannot speak about an absolute rest of the aether, is self-evident; this expression would not even make sense." Einstein is essentially saying the same thing in 1909 when he says that Lorentz needed no hypotheses about the aether except that it did not participate at all in the motions of matter. Some people read a lot into that "at rest" phrase, but Lorentz explicitly disavows meaning an absolute rest of the aether. He only means that he is rejecting Stokes' view. [[User:Schlafly|Roger]] ([[User talk:Schlafly|talk]]) 10:59, 21 March 2012 (UTC)

::::: He was rejecting Stokes's view by preferring Fresnel's view. Saying that the aether is at rest or that the aether doesn't share the motion of matter means exactly the same. Observationally this leads to the so-called "aether wind", which is hidden by local time (1892, 1895) to first order, but whose second order effect should be detected by the Michelson-Morley experiment. But also this effect was hidden by an additional hypothesis: length contraction (1892). Other second order effects should lead to torsion due to electrostatic fields, and double refraction ([[Trouton–Noble experiment]], [[Experiments of Rayleigh and Brace]]). To avoid those effects, local time had to be extended to all orders in v/c (1904). PS: It's a philosophical question whether you call the motion between aether and matter (= aether wind) "absolute" or "relative". Many are calling it absolute, Lorentz himself called it "relative" ([[s:The Relative Motion of the Earth and the Aether]]). So there is an aether-wind in Lorentz's 1895 theory which has to be hidden by additional hypotheses, and the rejection of this aether wind and the whole aether concept is fundamental for special relativity. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 15:33, 21 March 2012 (UTC)

::::::See also Lorentz's 1895 description of the MM-experiment ([[s:Attempt of a Theory of Electrical and Optical Phenomena in Moving Bodies/Section VI|Section VI]]). There he also described the contraction hypothesis as an attempt "''...to remove the contradiction between Fresnel's theory and Michelson's result. Indeed this can be achieved by means of a hypothesis, which I already have spoken out some time ago ... If we assume, that the arm lying in the direction of Earth's motion, is shorter ... than the other one, and simultaneously the translation would have an influence which follows from Fresnel's theory, then the result of Michelson's experiment is fully explained.''". Lorentz again and again said on different occasions, that his model is the continuation and further development of Fresnel's stationary aether. --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 16:22, 21 March 2012 (UTC)

::::::: That is all correct. Lorentz said in that 1895 introduction, "so far none of the two contested theories, neither that of Fresnel, nor that of Stokes, were fully confirmed with respect to all observations ... By that I was long ago led to believe that with Fresnel's view, i.e. with the assumption of a stationary aether, we are on the right way." Lorentz was scrupulous about crediting others. He was careful to distinguish Fresnel from Stokes, and to say he preferred Fresnel. He goes on to explain the "difficulties for Fresnel's theory". So Lorentz likes Fresnel better than Stokes, but Fresnel is not the foundation for his proposed theory. The foundation is Maxwell's equations, Fizeau, and MMX. [[User:Schlafly|Roger]] ([[User talk:Schlafly|talk]]) 22:02, 21 March 2012 (UTC)
:::::::: The contraction hypothesis was Lorentz's attempt to remove the contradiction between the MM-experiment and Fresnel's (and thus his own) stationary aether as he clearly explained. These were the "difficulties for Fresnel's theory", which were '''solved''' by the contraction hypothesis. Lorentz chose Fresnel's aether model because it explained Fizeau's experiment. Without stationary aether and the related aether wind, neither "local time" nor "length contraction" would have been invented by Lorentz. Saying that there is an aether wind is the same as saying that the aether is immobile, and vice versa. This was clear to Lorentz himself and Einstein. The difference between Fresnel and Lorentz is, that Lorentz used Maxwell's electrodynamics, and that Lorentz's aether was completely immobile while Fresnel included partial aether drag (Fresnel's dragging coefficient) in moving media.  --[[User:D.H|D.H]] ([[User talk:D.H|talk]]) 08:54, 22 March 2012 (UTC)

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== Later Activity - Add statement regarding Sine-Gordon equation and quasi relativistic effects in crystals ==

I would like to add the following in the chapter Later Activity (My changes where undone by [[User:DVdm|DVdm]], I therefore start now a new section on this talk page following [[WP:BRD]]):

Helmut Günther also developed a Lorentzian model of an universal ether in 1996. This is based on the fact that dislocations in crystal structures exhibit quasi-relativistic effects such as longitudinal contraction and time dilation. This is because the Sine-Gordon equation on which these phenomena is based is Lorentz-invariant.

*{{Citation
|author=Günther, Helmut
|year=2000
|title= Elementary Theory of Relativity: Lattice - Ether - Symmetry
|place=Aachen
|publisher=Shaker Verlag
|isbn=978-3-8265-7104-6}}

That simple mechanical models can exhibit relativistic effects is not yet clearly stated in this article. There is also a German article that describes how to build a mechanical sine-gordon-chain (Dietrich, M. u.
H.-J. Patt: "Wellenmaschine zur Demonstration und Messung harmonischer und anharmonischer Wellenphänomene (Solitonen)" http://www.uni-saarland.de/fak7/patt/pdf/bre_diet.pdf). Fig. 12 in the later (German) paper shows two solitons, the left one is lorentz contracted. I hesitated to cite this document here as it is in German, but I did also not yet find an English paper. Helmut Günther explains in chapter 10 of the above cited book, how a breather exhibits time dilation. Apart from this he discusses the whole relativity theory with a Lorentzian approach. All these authors appear to be motivated by pedagogical reasons, as the Lorentzian approach is assumed to be easier to be understood by at least some students (You may see also https://arxiv.org/abs/1107.4748 for a discussion of how to teach relativistic). --[[User:Malanoqa|Malanoqa]] ([[User talk:Malanoqa|talk]]) 19:43, 19 May 2017 (UTC)

:Are there any solid [[wp:secondary sources]] that refer to Günther, to establish notability of this? Without such it seems pretty [[wp:UNDUE]] and [[wp:FRINGE]]. - [[User:DVdm|DVdm]] ([[User talk:DVdm|talk]]) 21:11, 19 May 2017 (UTC)

::Hi [[User:DVdm|DVdm]], thanks for "defending" the quality of this article. I saw that you reverted at least two times in the past edits where sources where added to this article. In both cases, I agree with your decision. 

::I will do my very best to to answer your question. Helmut Günther published mostly in German language.I assume that the Shaker Verlag that published the English translation of a book from 1996 would publish near to anything that appears scientific, so a text published there is not by itself a reliable source. The original text is in German and was published in 1996 by Springer Fachmedien Wiesbaden GmbH a part of Springer (https://www.amazon.de/Grenzgeschwindigkeiten-ihre-Paradoxa-Relativit%C3%A4t-Teubner-Texte/dp/3815430291/ref=sr_1_9?ie=UTF8&qid=1495260851&sr=8-9&keywords=G%C3%BCnther+Relativit%C3%A4tstheorie). Springer is a major publisher of scientific books and journals and books published there should qualify as reliable source. The most recent book by Helmut Günther about an at least related topic is from 2012 and also published by Springer (https://www.amazon.de/Die-Spezielle-Relativit%C3%A4tstheorie-Einsteins-Axiomatik/dp/3658007125/ref=sr_1_8?ie=UTF8&qid=1495260851&sr=8-8&keywords=G%C3%BCnther+Relativit%C3%A4tstheorie), but here I do not know in detail what is in the  book.

::So it appears to me, that it is better when I use the German text as reference. It is published by Springer, so I regard it as reliable source. And it will be much easier to find more reliable sources to support this if needed. But this reliable sources will then probably be also in German language.

::The reason that many texts are in German is probably that a main motivation for all this authors is their pedagogical work. And here teaching and writing is mostly in German language.

::The work by Helmut Günther is not original research. That certain physical systems (In Galilean space) can be described in the continuum approximation by the Sine-Gordon-equation is well known (under experts). The same is true for the Lorentz-invariance of the solutions of the Sine-Gordon-equations (although not yet written in the Wikipedia article about this equation). So a text book to teach relativity theory using this knowledge can be written. And this is what Helmut Günther did. --[[User:Malanoqa|Malanoqa]] ([[User talk:Malanoqa|talk]]) 07:08, 20 May 2017 (UTC)

:::Springer can be reliable, but it's still merely a [[wp:primary source]]. Compare this with the paragraph on [[John Stewart Bell]], which is also sourced with a PS, but we ''know'' that many SC could be found, ''and'' Bell has an article here, which makes it relevant and [[wp:DUE]]. At least one reliable [[wp:secondary source]] might establish sufficient relevance to mention Günther here. What do other contributors think? - [[User:DVdm|DVdm]] ([[User talk:DVdm|talk]]) 08:10, 20 May 2017 (UTC)

::::I search currently for more and better sources --[[User:Malanoqa|Malanoqa]] ([[User talk:Malanoqa|talk]]) 08:58, 20 May 2017 (UTC)
::::The German book by H. Günther from 1996 fullfills in my understanding the criteria of a reliable secondary source [[wp:secondary source]] as it is stated in this policy "... Secondary sources are not necessarily independent or third-party sources ...". Primary sources are for instance "Günther, H. (1988), On Lorentz Symmetries in Solids. phys. stat. sol. (b), 149: 101–109. doi:10.1002/pssb.2221490110" and "Günther, H. (1994), The Crystalline Structure as a Basis for a Reversed Access to the Special Theory of Relativity. phys. stat. sol. (b), 185: 335–340. doi:10.1002/pssb.2221850203" --[[User:Malanoqa|Malanoqa]] ([[User talk:Malanoqa|talk]]) 19:47, 20 May 2017 (UTC)
::::: Perhaps, but let's get other contributors' opinions on this first, in order to establish some kind of [[wp:consensus]] to make the change. - [[User:DVdm|DVdm]] ([[User talk:DVdm|talk]]) 20:32, 20 May 2017 (UTC)

:::::: Are they relativistic (SR) effects, or LET effects? Or is there a difference? Presumably any SR effect could be described as an LET effect, so there would be nothing notable about that. If for some reason LET works in this research but SR does not, then that would be interesting, but it would have to be explained. [[User:Schlafly|Roger]] ([[User talk:Schlafly|talk]]) 05:18, 21 May 2017 (UTC)
::::::: Indeed, explained, ''and'' in turn, sourced as well. - [[User:DVdm|DVdm]] ([[User talk:DVdm|talk]]) 08:44, 21 May 2017 (UTC)
::::::: The new aspect is, that certain kinds of solitons (for instance the solutions of the Sine-Gordon-Equations) exhibit relativistic effects. So there are model systems for the classical Lorentz ether. I regard this as an important information that should be mentioned in this article. I could try to write a new chapter "Physical models for a Lorentz ether"--[[User:Malanoqa|Malanoqa]] ([[User talk:Malanoqa|talk]]) 18:19, 21 May 2017 (UTC)
:::::::: Without secondary sources, that would be [[wp:synthesis]] and [[wp:original research]]. - [[User:DVdm|DVdm]] ([[User talk:DVdm|talk]]) 18:34, 21 May 2017 (UTC)
:::::::: I noted this secondary sources already, but they are in German languange and in books that are not freely available. So it is difficult to achieve [[wp:CON]] --[[User:Malanoqa|Malanoqa]] ([[User talk:Malanoqa|talk]]) 06:41, 22 May 2017 (UTC)
: There is a new book by Helmut Günther and Volker Müller "The Special Theory of Relativity: Einstein’s World in New Axiomatics (Englisch)" published by Springer (ISBN-10: 9811377820). Chapter 12 in this book describes a lattice model of Relativistic Space-Time. This might be used as secondary source. [[User:Malanoqa|Malanoqa]] ([[User talk:Malanoqa|talk]]) 17:30, 8 June 2020 (UTC)
::{{rto|Malanoqa}}, but that is still a [[wp:primary source]]. The idea is that we need [[wp:secondary source]]s that actually cite Günther's (primary) sources. That would establish whether the content is worth being mentioned here. - [[User:DVdm|DVdm]] ([[User talk:DVdm|talk]]) 18:12, 8 June 2020 (UTC)