Talk:Special relativity

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[edit] The second postulate

Carnildo's statement is: "The second postulate is three separate claims:

1. The speed of light is the same to all inertial observers 2. The speed of light is the same in all directions 3. The speed of light does not depend on the velocity of the emitter

The second claim was verified by the Michelson-Morley experiments, and the third was verified by the experiments that disproved emitter theory. For the third claim, [1] cites Alvager et al., Physics Letters 12, 260 (1964) as being the definitive study. I don't know of any experiments that that have verified the first claim, but I'm sure they're out there. --Carnildo 22:46, 10 Dec 2004 (UTC)" and he provided some verification about "one way" speed of light for the second claim.

I will try to make a test for the first claim and hope Carnildo can help to make it better or make it not valid:

We need 3 timers which are able to record nanoseconds. One built into a switch on-off red light bulb, one built into a switch on-off yellow light bulb, and one built into a camcorder. We synchronize the timers to the best we can and write down their related times: Tr, Ty, and Tc. We let Mr. Cam sets up the camcorder to record two events started from Tc+9 minutes to Tc+11 minutes. Mr. Red put the set of red light bulb on a table 30 meters away from the camcorder performs the first event, sets up the red light bulb be turned on at Tr+10 minutes then turned off at 20 nanoseconds later while Mr. Yel put the set of yellow light bulb on a tea table in between the table and camcorder, 6 meters away from the camcorder, performs the second event, sets up the yellow light bulb be turned on at Ty+10 minutes and 80 nanoseconds then turned off at 20 nanoseconds later.

We don't let Mr. Cam know the starting time of events. At Tc+22 minutes, three workers look at the recorded time which should show that the red light and yellow light were turned on at about Tc+10 minutes and 100 nanoseconds and lasted for 20 nanoseconds. They then calculate the speed of light from the known distance:

Mr. Red has 30 m / (100-0) ns = 0.3 m/ns and Mr. Yel has 6 m / (100-80) ns = 0.3 m/ns but Mr. Cam has some difficulty. The recorded two events happened at the same time means the event-starting pictures arrived the camcorder at the same time, Tc+10 minutes and 100 nanoseconds; but what are the event starting times? What is your answer? There are two answers, general publics will say according to the recorded vedio, both light bulbs was turned on at Tc+10 minutes and 100 nanoseconds; the other answer is don't know, depend on how far away are the light bulbs and since the speed of light is to be decided, unable to calculate the time. If Mr. Cam is one of the general public, then the result of calculation is 30 m / 0 ns and 6 m / 0 ns, unlimited fast. That is different from the results of Mr. Red and Mr. Yel.

(Note: Actually, all photons reach at our eyes are calculated by our brain like running at unlimited speed. :)) John C. Huang (talk) 20:04, 12 January 2008 (UTC)

Please stop adding your original research to article talk pages., DVdm (talk) 10:02, 13 January 2008 (UTC)

Thanks. I would not do it any more. However, could any one provide a verification for the first claim? I realy like to know. John C. Huang (talk) 16:35, 14 January 2008 (UTC)

See the article on "Speed of Light", especially the section on measurements of this speed, which have been carried out in different frames of reference (since the Earth is in different states of motion at different times of the year), and which consistently yield the same value. By 1972 this measured by Evenson as 299792.4574 ± .0012 km/s, regardless of the time of year.
Having said that, I should add that Wikipedia Talk pages are not to be used for asking people to explain the subject. 63.24.99.44 (talk) 06:23, 15 January 2008 (UTC)

Thanks for your concern. People don't know much about C, the speed of light. Photons do not need acceleration to reach C and the only light we can see or a camcorder can record is the light runs directly into our eyes or the lens. If the speed of gravity force and electromagnetic force are C then no matter how strong the electromagnetic force is applied to the electron, the speed of that electron can not be higher than C like a balloon pulled by a train cannot go faster than the train no matter how powerful the train is. We don't know much about C.

The measurements you mentioned about were not designed to verify the first claim. What is the speed of light recorded by a camcorder? Is that C? How do you calculate it? I was not asking for people to explain the subject. I asked people to help to think about it. John C. Huang (talk) 06:15, 24 January 2008 (UTC)

I have found a way to verify that the speed of light is unlimited fast when it runs toward the camcorder and the speed of light is C/2 when it runs away from the camcorder.
We replaced Mr. Yel by Mr. 24m and Mr. 12m, we also replaced the yellow light-bulb by two glass rings of diameters 24 inches and 12 inches both with width of 6 inches. The ring24 had clear bottom half and transitable red upper half (so that some of the red light would go through and some of the red light would reflect) and the ring12 had clear upper half and transitable yellow bottom half. We then replaced the red light-bulb by clear light-bulb and removed the tea table. Let Mr. 24m stretched out his right arm held the ring24 at distance of 24 meters away from the camcorder and Mr. 12m stretched out his left arm held the ring12 at distance of 12 meters away from the camcorder the centers of the clear light-bulb, ring24, ring12, and the lens of the camcorder were about on one straight line. Then Mr. Cam started recording and Mr. Red turned on the clear light-bulb for 20 ns. Then we reviewed what was recorded. The result should be quite like all the center light, upper red, and bottom yellow all lighted up at Tc+10 minutes and 100 ns and lasted for 20 ns. That verified that the speed of light from ring24 to ring12 is unlimited fast to the observer.

Then, we let Mr. Cam moved to under the table to record both rings. We let Mr. Cam started recording from Tc+29 minutes to Tc+31 minutes. Let Mr. Red turned on the clear light-bulb from Tr+30 minutes to Tr+30 minutes and 20 ns. After that, we reviewed the recorded result. We should see ring24 lighted at around Tc+30 minutes and 40 ns, lasted 20 ns; then ring12 lighted at around Tc+30 minutes and 120 ns, lasted 20 ns. The calculated speed of light from ring24 to ring12 is about (24m-12m)/(120ns-40ns)=0.15m/ns and that is about C/2. Do you think this experiment make sense?

Please help. Thanks. John C. Huang (talk) 17:34, 26 January 2008 (UTC)

This is not an original research, it is a fact. John C. Huang (talk) 17:47, 26 January 2008 (UTC)

But Einstein is the one who said the speed of light is the one constant in the universe and travels at the same speed in all reference frames so unless you think he is wrong, that can't be right. Skeletor 0 (talk) 16:31, 3 June 2008 (UTC)

[edit] Maxwell's Equations are NOT a Postulate of Special Relativity

Some editors have suggested inserting claims in the article to the effect that the lightspeed invariance postulate follows from Maxwell's equations, and that therefore the lightspeed postulate can be replaced by simply postulating Maxwell's equations. This is not accurate either technically or historically. As Einstein later explained, he already knew by 1905 (see his 1905 paper on light quanta) that Maxwell's equations were not fundamental, and in fact were wrong. He very specifically avoided basing special relativity on Maxwell's equations. Of course, he also explained in several places that if we assumed Maxwell's equations had the same form in all systems of inertial coordinates then the lightspeed postulate follows, but this is to assume much more than is needed. Also note that Lorentz assumed Maxwell's equations too, but only for the system of space and time coordinates at rest in the ether, and hence Maxwell's equations need not be understood to imply lightspeed invariance. Maxwell himself understood this and wrote about it. Look, whole books have been written about why Einstein specifically chose to base special relativity on the two postulated that appear in the 1905 paper. It would bog down the article to explain all this in detail. But the article needs to be written in a way that is consistent with both the technical facts and the historical facts, and this can only be done by people who are acquainted with both. Notice that the claims inserted in the article about special relativity being based on Maxwell's equations are unsourced. This is because the editor(s) inserting those claims are really just inserting (erroneous) "original research", i.e., their own (mis)conceptions. It would be beneficial to the article (in my opinion) to remove those erroneous and misguided statements.Denveron (talk) 15:51, 17 February 2008 (UTC)

It is not OR - I have read many times that Einstein derived SR from MEs. BTW no one is claiming that "ME are a postulate of SR", so I don't what the point of the section title is. --Michael C. Price talk 16:37, 17 February 2008 (UTC)
I believe you're mistaken when you say no one is claiming ME are a postulate of SR. Here is what you inserted into the article in a recent edit: "Einstein derived the second postulate about the invariance of the speed of light from the first postulate, by applying the principle of relativity to Maxwell's equations". Needless to say, this is a weird statement in several respects... for example, it talks about "deriving" a postulate. But even if we overlook this weirdness, your assertion is clearly that the foundation of special relativity is the principle of relativity combined with Maxwell's equations, from which (you assert) the lightspeed postulate is "derived". Hence you are making Maxwell's equations an underlying postulate, smuggling it in through the back door. This, as I explained above, is wrong. Einstein specifically avoided basing special relativity on Maxwell's equations, because he already knew Maxwell's equations were not fundamentally correct. Of course, he also knew they contained an important kernal of truth, which he extracted in the form of the lightspeed invariance postulate, which is just as valid in quantum electrodynamics as it was in Maxwellian electromagnetism.
To say "Einstein derived special relativity from Maxwell's equations" is so vague as to be neither true nor false. Certainly the Lorentz invariance of Maxwell's equations was a crucial fact, so in that sense it is true. But Maxwell's equations were already known to be not fundamental, so it was necessary to identify the key feature of those equations, and the single simple fact that must underly any successful theory of electromagnetism. This was the principle of lightspeed invariance. It is formally a principle that was inferred from (among other things) the success of Maxwell's equations, but this principle cannot be "derived from" Maxwell's equations unless we first postulate Maxwell's equations, which we know are wrong at the fundamental level.
I would just say that any claims in the article ought to be supported by direct quotes from reputable sources, and not just paraphrases based on editors assurances that they have "read many times that Einstein derived SR from MEs". The undeniable fact is that Einstein's 1905 paper explicitly derives special relativity not from Maxwell's equations, but from two principles, one being lightspeed invariance. This has proven to be a sound basis, even after Maxwell's equations were shown to be wrong. Claims that special relativity assumes the validity of Maxwell's equations are simply wrong. This is one of the great features of special relativity... the solidity of its premises.63.24.127.205 (talk) 17:18, 17 February 2008 (UTC)
There is nothing "weird" about my claim, nor is it an isolated claim of a relativity crank: Einstein's first postulate is that the physical laws of nature are the same in all inertial reference frames. His second postulate is simply a consequence of applying this principle to the laws of electricity and magnetism......Einstein's first postulate seems perfectly reasonable. And his second postulate follows very reasonably from his first. How strange that the consequences will seem so unreasonable. --Michael C. Price talk 17:41, 17 February 2008 (UTC)
As for sources, look at the footnote from AE's 1905 relativity second paper, which never mentions the second postulate, only the first, instead saying: "The principle of the constancy of the velocity of light is of course contained in Maxwell's equations." So there you have it, from the horse's mouth itself! --Michael C. Price talk 17:44, 17 February 2008 (UTC)
First, one does not derive postulates, so the weirdness (to put it kindly) of your assertions is beyond dispute. Second, the point of view you are expressing is a well-known and (unfortunately) fairly common misunderstanding among relativity newbies. When you say the lightspeed postulate follows from applying the relativity postulate to the laws of electricity and magnetism you are assuming those laws are given in advance, just as you could assume the laws of mechanics were given in advance. However, both the Newtonian and the Maxwellian laws are wrong (as we now know). Einstein says the relativity postulate must apply to the laws of electrodynamics as well as to the laws of mechanics - whatever those laws may be. In point of fact, it turned out that the laws of both mechanics and electrodynamics had to be modified in order to make them consistent with the principle of relativity and the principle of lightspeed invariance. The laws of mechanics were modified immediately beginning in 1905, and the laws of electrodynamics were modified when quantum mechanics was finally reconciled with special relativity by Dirac, eventually resulting in quantum electrodynamics. The point is, neither the laws of mechanics nor the laws of electrodynamics are premises of special relativity. Rather, special relativity imposes conditions on the form those laws must take.
Of course, it is true that Einstein included a footnote about Maxwell's equations in the "Inertia of Energy" paper in 1906, but that footnote does not say that special relativity is based on Maxwell's equations. It merely observes (correctly) that if Maxwell's equations are valid in terms of every system of inertial coordinates, then the lightspeed invariance follows. But as Einstein already knew, Maxwell's equations are NOT valid in ANY system of inertial coordinates, so it would have been considerably less brilliant of him to found special relativity on those equations. In the "Inertia" paper he is simply trying to make the lightspeed principle seem more plausible to people who were not accoustomed to it by relating it to Maxwell's equations, with the tacit proviso that they are held to be valid in terms of all systems of inertial coordinates.
This is why I didn't want to get into this in detail, because to give an accurate representation of the fact, you must include not just the footnote in one paper that doesn't even support your point, but the texts of the dozens of presentations of special relativity that Einstein wrote over his lifetime, in which he clearly and repeatedly emphasized that special relativity is based on lightspeed invariance, NOT on Maxwell's equations. You are obviously intent on inserting your POV into the article, and it will be quite easy to bury you in citations proving you wrong, but is this really a good use of anyone's time? Why not go and acquaint yourself with the vast literature?63.24.32.26 (talk) 20:07, 17 February 2008 (UTC)
One more point - the quotation of the footnote you gave was incorrect, as it omitted the two crucial words "used there". You aren't entirely to blame for this, because those words were omitted from the Dover booklet translation that most newbies read. To see what Einstein actually wrote, see the original German, or read the English translation in the Collected Papers (Princeton University Press). By saying "the principle of the constancy of the velocity of light USED THERE" he is re-affirming that this is the principle on which special relativity is founded, and then going on to add in a comforting way (for people who have more faith in Maxwell's equations than in Einstein's lightspeed principle) that Maxwell's equations imply the lightspeed invariance... with the tacit assumption that Maxwell's equations are valid with respect to every system of inertial coordinates, but since c appears in Maxwell's equations (as the ratio of electrostatic to magnetic units), this tacit assumption is tantamount to the assumption of lightspeed invariance. So lightspeed invariance follows from the assumption of lightspeed invariance. This is the only aspect of Maxwell's equations on which special relativity is founded. Hence your insistence on trying to give readers the impression that special relativity is based on some feature of Maxwell's equations other than lightspeed invariance itself is both technically wrong and historically inaccurate. Please stop.63.24.105.109 (talk) 20:38, 17 February 2008 (UTC)
  1. The inclusion of the words "used there" makes no difference to the meaning (which is why it probably was left out by the translators).
  2. I am not a relativity "newbie", so you can stop all the insinuations. I have a BSc (physics) and MSc (quantum field theory).
  3. I guess it was naive of me to think that presenting you with the source you asked for would actually change your mind, but that isn't important; what is important is that my POV (as you call it) has an unimpeachable source.
  4. And please give up all the elementary physics lessons about Maxwell's equations not being fundamental -- a complete red herring, since we are talking about classical mechanics here, not quantum mechanics. It is your position that is sounding like original research, not mine.
  5. Please provide sources for your claim that Einstein sought to avoid basing SR on MEs. The two foundational 1905 papers do not provide any evidence to support this view. Quite the contrary, they make continual reference to Maxwell and "electrodynamics". --Michael C. Price talk 20:55, 17 February 2008 (UTC)

Answers: 1) The words "used there" obviously make a very significant difference, which is why the more careful translators DID include it. Your (incorrect) version of the quote was the basis of your (erroneous) claim that the lightspeed postulate was not contained in the Inertia paper, but then you quoted the note that contained it, referring back to the foundational paper. 2) Don't care. 3) You call your mis-contrual of a mis-quotation an "unimpeachable source". I would hate to see what you consider an impeachable source. 4) You are confused. The topic here is special relativity, which is just as valid in quantum electrodynamics as in mechanics. Of course, neither of these are in their classical form, but that's the whole point. They had to be modified to be consistent with special relativity. If we took Maxwell's equations for granted (as you suggest we should do in founding special relativity), it would be incompatible with quantum electrodynamics. Fortunately, special relativity is not founded on Maxwell's equations, it is founded on the existence of an invariant speed. Your efforts to conflate these two things are not helpful. 5) Done. See the edited article.63.24.112.17 (talk) 23:31, 17 February 2008 (UTC)

Your entire position is one of OR, since the quotations provided do not demonstrate your case, only the lack of your ability to see both sides of the argument. The fact remains that back in 1905 Einstein dropped the 2nd postulate because he could derive it from the principle of relativity applied to Maxwell's equations. Here I quote the opening of his 2nd paper with the footnote inserted:

The results of the previous investigation lead to a very interesting conclusion, which is here to be deduced.

I based that investigation on the Maxwell-Hertz equations for empty space, together with the Maxwellian expression for the electromagnetic energy of space, and in addition the principle that:--

The laws by which the states of physical systems alter are independent of the alternative, to which of two systems of coordinates, in uniform motion of parallel translation relatively to each other, these alterations of state are referred (principle of relativity).

With these principles (The principle of the constancy of the velocity of light used there is of course contained in Maxwell's equations.) as my basis I deduced .....

What could be clearer! Three references to Maxwell. No second postulate.--Michael C. Price talk 00:11, 18 February 2008 (UTC)

Maxwell's equations are both too much and not enough to serve as a foundation for special relativity, and this is clear from all the vast literature on this subject. They are not enough because it is entirely possible to reconcile a Lorentzian view of Maxwell's equations with the principle of relativity without implying invariant light speed. (See Lorentz's theory.) They are too much because if you add the (necessary) stipulation that they must apply in the same form, with the same ratio of electric to magnetic units, in terms of all inertial frames, then they not only imply the invariance of light speed, they also imply a whole lot of other things... many of which are not true. Furthermore, to say that you can eliminate the second postulate by substituting another postulate (Maxwell's equations) and declining to call it a postulate is just, well, I'll refrain from characterizing it. 63.24.118.18 (talk) 02:39, 18 February 2008 (UTC)

Again, irrelevant OR. It doesn't alter the fact that Einstein used Maxwell's equations to derive c, and dropped the 2nd postulate in his 2nd paper. What he did towards the end of his life doesn't alter the historical record for 1905. --Michael C. Price talk 08:35, 18 February 2008 (UTC)
Einstein's paper on the inertia of energy is not a second attempt to derive special relativity, it is an attempt to show that at least some forms of energy have inertia, and for this limited derivation he stipulated Maxwell's equations (as covariant laws). Of course, this postulate contains as a subset the postulate of invariant lightspeed, so it in no way obviates the lightspeed postulate. It augments the lightspeed postulate with even more postulates, some of which Einstein already knew to be false, but which he needed in order to make his argument for the inertia of energy. Now, this particular derivation of mass-energy equivalence was criticized by many scientists, including Planck, not least because of its reliance on Maxwell's equations. (This derivation has also been assessed as circular reasoning, even by some admirers of Einstein.) In his 1907 paper Einstein felt compelled to apologize for having based his argument on Maxwell's equations, which was unnecessary, and which he already knew to be wrong, but he justified it by saying that he thought the use of Maxwell's equations would lead to reasonable results in the particular cases where he used them. But the point is that it's utterly idiotic to say that Einstein "dropped the 2nd postulate" when he (on these rare occasions) postulated Maxwell's equations. Those equations are then "the 2nd postulate", and they contain the invariant lightspeed postulate (which we already know is sufficient to derive the Lorentz transformation) PLUS many more individual postulates. It's as if you brought a cow, two horses, and three pigs into the barn, and then you claim that you didn't bring a cow into the barn. Please. It is very well known that the principle of relativity, alone, is not sufficient to single out special relativity. Some other postulate is required. Now, it is certainly true that there is a wide choice of possible 2nd postulates to augment the relativity postulate, but they all amount to lightspeed invariance. See, for example, the discussion in Rindler. This is all very old hat, and goes all the way back to the early days of relativity, with the likes of Ignatowsky arguing with Ehrenfest. I urge you to acquaint yourself with the literature on this subject.63.24.124.104 (talk) 04:04, 19 February 2008 (UTC)

Once again an irrelevant response that shows your total inability to see both sides of an argument. Again, it doesn't alter the fact that Einstein used Maxwell's equations to derive c, and, for this reason, dropped the 2nd postulate in his 2nd paper. What he did towards the end of his life doesn't alter the historical record for 1905, nor does it diminish the utility of understanding the origins and motivation of SR (or any subject) as a modern day pedagogical tool. --Michael C. Price talk 08:35, 18 February 2008 (UTC)

Einstein certainly claimed in the 27th September addendum to his 1905 paper that he drew heavily upon Maxwell's equations. And he did state in that paper that the constancy of the speed of light was inherent in Maxwell's equations.
But it is a matter of opinion as to whether the content of Maxwell's original works bears any relationship whatsoever to Einstein's works. Nobody having studied Maxwell's original works would see the slightest similarity between what he was doing and what Einstein was doing. It is likley that Einstein misunderstood Maxwell's equations. David Tombe (talk) 11:39, 8 June 2008 (UTC)
I hardly think that it is a matter of opinion as to whether the content of Maxwell's original works bears any relationship whatsoever to Einstein's works. Any relationship? As for It is likley that Einstein misunderstood Maxwell's equations. You must be kidding or very ill-informed. Please enlighten us as to how "Einstein misunderstood Maxwell's equations". --Michael C. Price talk 14:06, 8 June 2008 (UTC)

Michael, there is not the remotest similarity between Maxwell's work and Einstein's work.

I agree with you that Einstein claimed to have drawn on the so-called Maxwell-Hertz equations. But in what respect? It is true that the E = mc^2 can be derived from a lesser known equation by Maxwell that is connected with radiation pressure. But that radiation pressure equation never appears in either modern sets of Maxwell's equations or in Maxwell's original eight equations.

Maybe it is the radiation pressure equation that Einstein is referring to but he doesn't make that clear.

At any rate, there is nothing at all in Maxwell's original works that says that the speed of light is a universal constant.

I had always assumed that the constancy of the speed of light was an Einstein idea which he derived from the Michelson-Morley experiment.

Perhaps you would like to tell me what exactly Einstein saw in Maxwell's equations that led him to his theory of relativity. For Maxwell, the speed of light was the mach number in a sea of elastic molecular vortices and it never possessed any of the special relativity properties that Einstein later attributed to it. David Tombe (talk) 09:53, 9 June 2008 (UTC)

Perhaps you would like to tell me what exactly Einstein saw in Maxwell's equations that led him to his theory of relativity. Again, I quote Einstein 1905:
With these principles (The principle of the constancy of the velocity of light used there is of course contained in Maxwell's equations.) as my basis I deduced .....
BTW Einstein probably never heard of the Michelson-Morley experiment at the time.--Michael C. Price talk 10:38, 9 June 2008 (UTC)

Michael, we had already agreed that Einstein said that in his 1905 paper. But it just goes to show how little Einstein understood Maxwell's equations. because they don't imply the universal constancy of the speed of light. If you read Maxwell's papers, you will see that he calculated that speed using Newton's eqation for the speed of sound in connection with an elastic medium. He saw the speed of light as the mach number for that medium measured at a stationary point in that medium. David Tombe (talk) 11:39, 9 June 2008 (UTC)

David, Maxwell's interpretation of his equations are irrelevant: we are talking about Einstein's interpretation. No one disputes that the two interpretations are different. See also DH's comments below. --Michael C. Price talk 12:16, 9 June 2008 (UTC)
Regarding to some discussions above: Einstein's 2nd postulate and his view of Maxwell's equations was based on Lorentz's formulation of Maxwell's theory (the so called "Maxwell-Lorentz equations").
  1. Einstein said in his 1909-paper: "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 invariance of the speed of light principle."
  2. And in his 1912-paper Einstein wrote: "It is widely known that based on the principle of relativity alone a theory of transformation laws of space and time can not be established. It is known that this is connected with the relativity of "simultaneity" and "the shape of moving bodies". To fill this gap, I borrowed from H.A. Lorentz's stationary light-ether theory the principle of constancy of the speed of light, which like the relativity principle is a physical condition that is only justified by the pertinent experience (experiments by Fizeau, Rowland, etc.)."
  3. And in his nobel lecture (1921), he said: "The special theory of relativity is an adaptation of physical principles to Maxwell-Lorentz electrodynamics...From Maxwell-Lorentz electrodynamics it takes the postulate of invariance of the velocity of light in a vacuum (light principle).
See also History of special relativity and the works of Holton, Miller, Stachel...--D.H (talk) 12:01, 9 June 2008 (UTC)

Well of course that would make alot more sense. In other words Einstein wasn't referring to Maxwell's original works at all. Fair enough. We all knew all along that Einstein was influenced by Lorentz, and the connection is indeed clear.

It still however leaves a mystery as to what he meant by the Maxwell-Hertz equations in the 27th Sept. Addendum to his 1905 paper. The only Maxwell equation that could possibly be relevant to E = mc^2 is Maxwell's radiation pressure equation which never appears alongside Maxwell's equations. David Tombe (talk) 13:10, 9 June 2008 (UTC)

Einstein talked about "Maxwell-Hertz equations for empty space together with the Maxwellian expression for the electromagnetic energy of space". Those things were discussed in §§ 6-8 in the electrodynamics paper. BTW: As shown by Miller (1981), Einstein took many expression from Max Abraham, who was the first to use the terms "Maxwell-Hertz" and "Maxwell-Lorentz" equations, or "longitudinal" and "transverse" mass.--D.H (talk) 15:29, 9 June 2008 (UTC)

But basically Einstein doesn't appear to have had any direct knowledge of Maxwell's actual works. He seems to have worked on other people's developments of Maxwell's works. David Tombe (talk) 16:25, 9 June 2008 (UTC)

So when Einstein said "The principle of the constancy of the velocity of light used there is of course contained in Maxwell's equations." he was just talking through his arse, right? --Michael C. Price talk 16:31, 9 June 2008 (UTC)

@David Tombe: Holton (1973, 1988) points out that August Föppl's (1894) book on electrodynmics was Einstein's most important source for Maxwell's theory. Föppl presented Maxwell's theory in the formulation of Heaviside and Hertz and discussed the important moving magnet and conductor problem. Later, other possible sources for (variations) of Maxwell's theory were some papers of Boltzmann, Helmholtz, Drude, Lorentz, Abraham. So there were many different versions of "Maxwell's" theory - at the end Lorentz's formulation was the winner. ;-) --D.H (talk) 16:55, 9 June 2008 (UTC)

And Heaviside's. Don't we use Lorentz–Heaviside units today? My understanding is these were just different formulations of the same theory.--Michael C. Price talk 17:51, 9 June 2008 (UTC)

[edit] History of this talk page

This is just a heads up that I've undeleted the history of this talk page, formerly at Talk:Special relativity/Archive2 and moved it to Talk:Special relativity/Page history. Neither the history page nor the the redirect should be deleted because they contain backlinks. I could not do a straight history merge to this page because the histories overlap. Graham87 01:25, 3 June 2008 (UTC)