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Natural Science Forum / Physics / Research / October 2007Relativity without tears
"Relativity without tears" can be found here http://uk.arxiv.org/abs/0708.0929 I'll appreciate corrections of English. Other comments are also welcomed. > "Relativity without tears" can be found herehttp://uk.arxiv.org/abs/0708.0929 > I'll appreciate corrections of English. Other comments are also > welcomed. As a part-time academic editor (mainly for management science), and with physics as a hobby (PhD in theoretical chemistry, some time ago), I'd be happy to do the English correction if you email me for details at pellis@london.edu P. > "Relativity without tears" can be found herehttp://uk.arxiv.org/abs/0708.0929 > I'll appreciate corrections of English. Other comments are also > welcomed. You say: Because for Newtonian intuition "to take as a postulate that the speed of light is constant relative to changes in reference frame is to assume an apparent absurdity. It goes against common sense. No wonder, thinks a student, that we can derive other absurdities, such as time dilation and length contraction, from the premises"[5]. But is this really so absurd? It may go against common sense initially, but surely it can be accepted with little pain? The rocket ship goes faster, time dilates. Where's the problem in accepting that? It's just a fact like any other. Accepting quantum mechanical paradoxes is much more of a problem. > > "Relativity without tears" can be found herehttp://uk.arxiv.org/abs/0708.0929 > > I'll appreciate corrections of English. Other comments are also [quoted text clipped - 13 lines] > It's just a fact like any other. Accepting quantum mechanical > paradoxes is much more of a problem. i think that for Einstein, it there was no non-absurd option other than the speed of the same bean of light had to be constant relative to different inertial observers. given the axiom that the laws of physics are the same for every inertial observer (and why shouldn't they be?), then it is that Maxwell's equations are those laws of physics that, if identical in every respect for any and every inertial observer, is the principle from where you deduce that the speed of light in vacuo is the same for every observer. so you have this changing E field that is causing this changing B field that is causing this changing E field that is causing this changing B field that is causing this changing E field that is causing this changing B field and all that changing E and B field is, by solving Maxwell's equations, propagating at this speed, c = 1/ sqrt(eps0*mu0), would not two inertial observers, both moving relative to the other and both observing the same little beam of light (doesn't matter which of them might be holding the flashlight), measure that speed to be the same for each observer? they have the same eps0 and mu0, don't they? why should one observer be preferred over the other (which is what would have to be the case if one measured c to be different than the other) so that this one observer has the more "correct" value for c? r b-j __________________ > > > "Relativity without tears" can be found here > > > http://uk.arxiv.org/abs/0708.0929 [quoted text clipped - 25 lines] > from where you deduce that the speed of light in vacuo is the same for > every observer. You are going round in circles. > so you have this changing E field that is causing this changing B > field that is causing this changing E field that is causing this [quoted text clipped - 9 lines] > different than the other) so that this one observer has the more > "correct" value for c? There is no reason at all why the laws of physics have to be the same for every observer. We have found this to be the case, but we can imagine other universes where such would not be the case. Other possibility: The privileged observer is the one for whom Maxwell's eqns hold in their simplest form. For all others there are extra terms, related to their motion. In fact, untill Einstein showed otherwise everyone believed this to be the case. Compare for example with Newtonian mechanics under rotation. There is one priv-ed observer (the non-rotating one) for whom the planets move under Newtons laws in their simplest form. For all other observers there are extra terms. (Coriolis and centrifugal) There can be no 'logical' or 'natural' reason why our universe can't be like this with respect to Maxwell's eqns, only an empirical one. And that only within experimental limits on preferred frame effect. Best, Jan > > > > "Relativity without tears" can be found here > > > >http://uk.arxiv.org/abs/0708.0929 [quoted text clipped - 27 lines] > > You are going round in circles. i didn't think so, Jan. i start with the *axiom* that the laws of physics are the same for every inertial observer. there is no circular path that takes me there. it's an axiom, but one that is more sensible and consistent than the contrary which would be (as you describe below) the case that some inertial observers get one set of laws of physics and some other inertial observers get some other set of laws (even if the difference between these sets of laws are merely different coefficients). now, conceivable the latter can sorta make sense if the coefficients that we're referring to are the *dimensionless* parameters like the 26 enumerated by John Baez (so one inertial observer has an alpha of 1/137.036 while another has an alpha of 1/137.037 and something would be measurably and operationally different for the two inertial observers). but this doesn't make sense for a dimensionless parameter like c since different finite values for c, assuming all the dimensionless parameters remain constant, would only result in a change in scaling that would be not "operationally meaningful" as Michael Duff might call it. > > so you have this changing E field that is causing this changing B > > field that is causing this changing E field that is causing this [quoted text clipped - 15 lines] > but we can imagine other universes > where such would not be the case. but they would be goofy and not consistent. > Other possibility: > The privileged observer is the one for whom Maxwell's eqns > hold in their simplest form. > For all others there are extra terms, > related to their motion. their motion relative to what? why are they moving and the priviledged observer is not? > In fact, untill Einstein showed otherwise > everyone believed this to be the case. they had to, because they couldn't or didn't comprehend that time was not observed to be the same thing for every observer everywhere. > Compare for example with Newtonian mechanics under rotation. > There is one priv-ed observer (the non-rotating one) > for whom the planets move under Newtons laws in their simplest form. right. there *is* a difference between not rotating and rotating at a constant angular speed. there is a difference between no acceleration and some non-zero acceleration. > For all other observers there are extra terms. > (Coriolis and centrifugal) yup. those other observers are accelerated. they are not inertial. > There can be no 'logical' or 'natural' reason > why our universe can't be like this > with respect to Maxwell's eqns, > only an empirical one. to me, thinking about some of the early thought experiments of the young Einstien, it certainly does seem less logical and natural that, in a vacuum where you cannot hook onto any tick marks or reference points, that one inertial observer has a different experience of life than another inertial observer. it's only because you're looking outside the train and referencing points on the ground assumed to be stationary, that there is any difference between you in the constant velocity train and the guy standing outside watching the train go by. i dunno. r b-j > > > > > "Relativity without tears" can be found here > > > > >http://uk.arxiv.org/abs/0708.0929 [quoted text clipped - 45 lines] > constant, would only result in a change in scaling that would be not > "operationally meaningful" as Michael Duff might call it. Your 'why shouldn't they be?' begs the question. There is no reason at all why they should be, except that we happen to know from experience that they are. > > > so you have this changing E field that is causing this changing B > > > field that is causing this changing E field that is causing this [quoted text clipped - 17 lines] > > but they would be goofy and not consistent. There is nothing goofy about preferred frame effects. On the contrary, they can be searched for. (with null results so far) > > Other possibility: > > The privileged observer is the one for whom Maxwell's eqns [quoted text clipped - 4 lines] > their motion relative to what? why are they moving and the > priviledged observer is not? To the world aether of course. Seriously though: the priviledged observer is the one who doesn't see preferred frame effects. For the time being we are all priv-ed but there is (and can be) no -logical- reason why this happy state of affairs must continue forever, with increasing precision of the experiments. > > In fact, untill Einstein showed otherwise > > everyone believed this to be the case. [quoted text clipped - 14 lines] > > yup. those other observers are accelerated. they are not inertial. Round in circles again. You only know these observers are inertial -because- they see no inertial forces. (unless you invoke Mach's principle, which is another postulate) Best, Jan .. > > > > given the axiom that the laws of physics are the same for every > > > > inertial observer (and why shouldn't they be?), .. > Your 'why shouldn't they be?' begs the question. > There is no reason at all why they should be, > except that we happen to know from experience that they are. .. > > > There is no reason at all why the laws of physics > > > have to be the same for every observer. [quoted text clipped - 5 lines] > > There is nothing goofy about preferred frame effects. i think there is. besides not being inconsistent with Michaelson- Morley, there is a preferrence of simplicity for it. i don't think the fundamental mechanisms of interaction in Nature would bother to take on a Rube-Goldberg description even if some current descriptions of reality are still comparable to such. however, i think that history is consistent with that science advances more rapidly or even sorta revolutionary when a description of it takes on a much simpler form and it is still widely encompassing. stuff like Maxwell's Equations, which literally inspired Einstein - he admired and was jealous of Maxwell for tying up all of EM in 4 pretty concise equations. so, if there is currently an icky description of some physical interaction, i think there is hope and even that it is the more reasonable expection that this icky description of some interaction is a result of our lack of depth of understanding of it rather than that the actual physical reality really *is* this icky relationship. > On the contrary, they can be searched for. > (with null results so far) so you're expecting not-null results in the future? > > > Other possibility: > > > The privileged observer is the one for whom Maxwell's eqns [quoted text clipped - 6 lines] > > To the world aether of course. :-0 > Seriously though: the priviledged observer is the one > who doesn't see preferred frame effects. > For the time being we are all priv-ed > but there is (and can be) no -logical- reason > why this happy state of affairs must continue forever, i think that science is advanced when the fundamental description of it is understood in a manner that is "as simple as possible, but not simpler." > with increasing precision of the experiments. but there are limits to that too, no? i'm not as sanguine as you that with some finite increase in limits of some instrumentation that data points, sufficient in number and confidence, will lie outside the range that is predicted within the current model (say GR or for little things, the Standard Model). .. > > > Compare for example with Newtonian mechanics under rotation. > > > There is one priv-ed observer (the non-rotating one) [quoted text clipped - 10 lines] > > Round in circles again. i don't know why you say so. if you're not inertial, your description of physics (in your accelerated frame of reference) has more terms on it. fewer terms in the inertial frame of reference. why is that circular? > You only know these observers are inertial > -because- they see no inertial forces. i don't know exactly what you're saying here, Jan. i don't think i disagree with it, but i dunno what is salient in it that i am missing. > (unless you invoke Mach's principle, > which is another postulate) isn't that also the currently-held orthodoxy? anyway, Jan, i'm not a physicist, i'm just an electrical engineer that does signal processing for a living - with an interest in some of this stuff, but i still think it's not philosophically dangerous to expect more simplicity in the description of nature as science advances. r b-j robert bristow-johnson says... >> There is no reason at all why the laws of physics >> have to be the same for every observer. [quoted text clipped - 3 lines] > >but they would be goofy and not consistent. I'm not sure whether this helps, but another way of looking at things is in terms of what are the fundamental scalar, vector and tensor fields of various theories. Galilean relativity has universal time, which means a scalar field T(P) associated with every point P in spacetime. It also has a 3D spatial metric tensor g_ij that applies to submanifolds consisting of all points P with the same value of T(P). These fields are non-dynamic. They are God-given and are not affected by matter or forces. If you try to include Maxwell's equations, without giving up the universal time T, then you are forced to introduce a preferred frame of rest. This amounts to a vector field U^u(P), which is the 4-velocity of a particle at rest in the preferred frame. Again, this vector is non-dynamic. Special Relativity gets rid of the nondynamic scalar field T and also the nondynamic vector field U^u. But it keeps the nondynamic metric tensor g_uv (extending it to cover arbitrary vectors in spacetime). General Relativity, in contrast, has no nondynamic scalar, vector or tensor fields. So the "goofy" fact about Maxwell's equations in the context of Galilean absolute time is just that there is a mysterious vector field U^u that determines an absolute frame of rest. But why should a nondynamic vector field be any more mysterious than a nondynamic scalar field (as in Galilean relativity) or tensor field (as in Special Relativity)? -- Daryl McCullough Ithaca, NY > "Relativity without tears" can be found herehttp://uk.arxiv.org/abs/0708.0929 > I'll appreciate corrections of English. Other comments are also > welcomed. Simply awful. You took a perfectly easy to understand, physically motivated theory and made into something grotesque and strange. It was interesting to bring up projective metrics (see below), but you totally botched that too. Light cone: (x-t)(x+t) = 0 -> Minkowski metric (affine, not projective geometry). Circular points at infinity: (x+iy)(x-iy) = 0 -> Euclidean metric (also affine). Can *anyone* think physically these days? -drl > "Relativity without tears" can be found here > http://uk.arxiv.org/abs/0708.0929 > I'll appreciate corrections of English. Other comments are also > welcomed. At the time, 1905, hadn't the constancy of the speed of light been experimentally demonstrated? Starlight aberration? Michelson-Morley? Wasn't it the case that the theorists were turning themselves inside out trying to avoid the contradictions? Einstein just accepted experimental evidence. > > "Relativity without tears" can be found here > > http://uk.arxiv.org/abs/0708.0929 [quoted text clipped - 3 lines] > At the time, 1905, hadn't the constancy of the speed of light been > experimentally demonstrated? How could you possibly demonstrate such a thing -experimentally-? > Starlight aberration? Michelson-Morley? Wasn't > it the case that the theorists were turning themselves inside out trying to > avoid the contradictions? Einstein just accepted experimental evidence. On the contrary, he postulated the constancy of the speed of light, and after that all the experimental evidence suddenly made sense, (with some reinterpretation) Jan >> Zurab Silagadze wrote in >> [quoted text clipped - 17 lines] > >Jan It also dawned on Einstein that simultaneous events aren't simultaneous to all observers: time was not as Newton believed it to be. That's when things really made sense. The constancy of the speed of light was an outgrowth of that. I believe that was the historical sequence. The constancy of the speed of light in a vacuum is built into Maxwell's Equations. That was known well known at the time; Einstein alludes to that in his 1905 paper. The need for an aether was laid to rest by his paper.[1] There was a great deal of experimental evidence before the paper that could not verify an aether: Einstein had been shown them by his professor Heinrich Weber. Poincare's shortcoming was that he could never dismiss the aether as an unnecessary construct (Lorentz also believed in the aether). Einstein had no such problem. [1] There is a slight bit of irony here. Einstein initially proposed a research thesis needed for graduation from ETH that was an experiment to measure the the speed of the earth through the aether. Weber disallowed the topic because it was done, unknowingly to Einstein, some 13 times before. Weber introduced Einstein to a paper by Wien which discussed the measurements. [snip] > [1] There is a slight bit of irony here. Einstein initially proposed a > research thesis needed for graduation from ETH that was an experiment to > measure the the speed of the earth through the aether. Weber disallowed > the topic because it was done, unknowingly to Einstein, some 13 times > before. Weber introduced Einstein to a paper by Wien which discussed the > measurements. A 2007 study sensitive to 10^(-16) relative employed two simultaneous interferometers over a year's observation: Optical in Berlin, Germany at 52°31'N 13°20'E and microwave in Perth, Australia at 31°53'S 115°53E. An aether background could never be at rest relative to both of them at any moment (local background) and certainly not over a year (galactic background). http://arXiv.org/abs/0706.2031 Phys. Rev. Lett. 99 050401 (2007) All spatial anisotropy measurments (Michelson-Morley experiments) and astronomical observations (vacuum circular dichroism via rotation of plane-polarized EM across the spectrum, from quasars and such) are conducted with photons (massless sector). They always null. Nobody has conducted a spatial anisotropy experiment in the massed sector to sufficient sensitivity (~10^(-13) relative). Affine and teleparallel gravitation theories specifically describe an anisotropic vacuum background toward chiral mass distribution. It is the only empirical disagreement between metric and non-metric gravitations. It is the *only* interesting place to look. Curiously, http://scitation.aip.org/prl/covers/99_12.jsp "these yield a new combined limit (blue ellipse) in good agreement with the standard model (black star)." Unless Uncle Al's eyes (and credulity) have gone sour, it looks like the Standard Model prediction is slightly *outside* observation. That is "poor agreement." There is a small chiral offset - consistent with a very dilute anisotropic chiral vacuum background. The vacuum should be left-handed in the massed sector and diastereotopically interact with parity-violating experiments beyond Standard Model predictions.  SignatureUncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/lajos.htm#a2 > >> Zurab Silagadze wrote in > >> [quoted text clipped - 26 lines] > Equations. That was known well known at the time; Einstein alludes to that > in his 1905 paper. The Maxwell equations say nothing of the kind. They say so -only with the additional assumption- that they hold in the same form for every (inertial) observer. This is what nobody believed before 1905, and what constituted Einstein's fundamental contribution. (generalised to the relativity postulate) Before Einstein it was believed that the Maxwell eqns would hold in their standard form for one priviledged obverser (the one at rest with respect to the world aether) and that for other observers there would be corrections to Maxwell's eqns. (to be searched for) Null results such as Michelson's were explained by various ad-hoc assumptions, such as a physically real Fitzgerald-Lorentz contraction. Best, Jan >> >> Zurab Silagadze wrote in >> >> [quoted text clipped - 29 lines] > >The Maxwell equations say nothing of the kind. Yes, they do. Perhaps stated in another way "Maxwell's equations,..., require that the process of the propagation of light in vacuo with the velocity c be independent of the frame of reference from which the process is observed.", Mechanics, A. Sommerfeld, p.11, Academic Press, 1952. >They say so -only with the additional assumption- >that they hold in the same form for every (inertial) observer. See above. >This is what nobody believed before 1905, >and what constituted Einstein's fundamental contribution. [quoted text clipped - 5 lines] >and that for other observers there would be corrections >to Maxwell's eqns. (to be searched for) I can find no reference that supports this. >Null results such as Michelson's >were explained by various ad-hoc assumptions, >such as a physically real Fitzgerald-Lorentz contraction. True. And it was indeed Einstein's "Theory of Relativity" that put an end to the aether construct. Strangely, after the General Theory of Relativity, Einstein began thinking about the aether again.[1] >Best, > >Jan [1] This and many more well-researched-historical notes may be found Walter Isaacson's "Einstein His Life and Universe," Simon & Schuster, 2007. Dans l'article <fd7346$hs9$1@e250.ripco.com>, arnow@iname.com (Murray Arnow) écrit: ] J. J. Lodder wrote: ] ] >Before Einstein it was believed that the Maxwell eqns ] >would hold in their standard form for one priviledged obverser ] >(the one at rest with respect to the world aether) ] >and that for other observers there would be corrections ] >to Maxwell's eqns. (to be searched for) ] ] I can find no reference that supports this. see for instance pages 811-812 of Lorentz' 1904 paper, "Electromagnetic phenomena in a system moving with any velocity smaller than that of light" available here: http://www.historyofscience.nl/search/detail.cfm?startrow=3&pubid=615&view=image Signature| ~~~~~~~~ Martin Ouwehand ~ Swiss Federal Institute of Technology ~ Lausanne __|___________ Email/PGP: http://personnes.epfl.ch/martin.ouwehand ____________ The need for big brains may be what explains the weakness of gravity [Brandon Carter] martin.ouwehand wrote: > Murray Arnow écrit: > [quoted text clipped - 15 lines] > http://www.historyofscience.nl/search/detail.cfm?startrow=3&pubid=615&view=ima >ge My understanding of "...in order to explain Michaelson's negative result, the introduction of a new hypothesis has been required, and that the same necessity may occur each time new facts will be brought to light. Surely, this course of inventing special hypotheses for each new experimental result is somewhat artificial. It would be more satisfactory. if it were possible to show, by means of certain fundamental assumptions, and without neglecting terms of one order of magnitude or another, that many electromagnetic actions are entirely independent of the motion of the system...." is that at least one person was unhappy with the introduction of a privileged reference frames. Besides Lorentz, Poincare and others was also trying to find a solution to this problem. I don't see where "it was believed," or generally accepted, that there should be a privileged reference frame. Dans l'article <fdbag8$afh$1@e250.ripco.com>, arnow@iname.com (Murray Arnow) écrit: ] My understanding of [excerpt from Lorentz' article] is that at least ] one person was unhappy with the introduction of a privileged reference ] frames. Lorentz, as most physicists at the time, would have been quite happy if Michelson and Morley had found evidence of one privileged reference frame (the Aether's). When they didn't, Lorentz had to face the situation and try to find an explanation, and I think you should say "compeled to abandon" instead of "unhappy with". But I pointed to those two page because they show that it came quite naturally to Lorentz to start his article by using different forms of Maxwell's equations in the Aether frame and in the moving frame, and I thought your remark "I can find no reference that supports this" was about this. Signature| ~~~~~~~~ Martin Ouwehand ~ Swiss Federal Institute of Technology ~ Lausanne __|___________ Email/PGP: http://personnes.epfl.ch/martin.ouwehand ____________ I don't want to seem frivolous though obviously I'm not, because I'm a physicist [Lisa Randall] > Murray Arnow écrit: > [quoted text clipped - 7 lines] >and try to find an explanation, and I think you should say "compeled to >abandon" instead of "unhappy with". The issue of preferred reference frames is an unhappy one. I don't think anybody wanted one since Galilean relativity didn't call for it. A need for an aether was there because it was difficult conceive of electromagnetic wave propagation without a media. This was one of those philosophical-gut-based arguments that consumed a lot time 100 years ago. I don't mean to deprecate this. After all, Einstein managed to reform physics with such considerations. >But I pointed to those two page because they show that it came quite >naturally to Lorentz to start his article by using different forms >of Maxwell's equations in the Aether frame and in the moving frame, >and I thought your remark "I can find no reference that supports >this" was about this. I was addressing Jan Lodder's statement, "it was believed," that there was a preferred reference frame before Einstein's 1905 paper. "Belief" meaning to be generally accepted was the point. I haven't seen where it was established and accepted that there should be a preferred reference frame. Dans l'article <fdj3lm$5gb$1@e250.ripco.com>, arnow@iname.com (Murray Arnow) écrit: ] I was addressing Jan Lodder's statement, "it was believed," that there was ] a preferred reference frame before Einstein's 1905 paper. "Belief" meaning ] to be generally accepted was the point. I haven't seen where it was ] established and accepted that there should be a preferred reference frame. maybe it wasn't formulated like that, but it was expected/hoped that it was possible to detect the movement of the earth with respect to the aether. Otherwise, how do you explain that people were surprised by the outcome of the Michelson-Morley experience ? But I agree that talking of a "preferred reference frame" may be a modern reformulation of this point of view. Signature| ~~~~~~~~ Martin Ouwehand ~ Swiss Federal Institute of Technology ~ Lausanne __|___________ Email/PGP: http://personnes.epfl.ch/martin.ouwehand ____________ Quantum mechanics raises not a single fresh metaphysical problem [M. Gardner] > Dans l'article <fdj3lm$5g...@e250.ripco.com>, > ar...@iname.com (Murray Arnow) ?crit: [quoted text clipped - 8 lines] > the aether. Otherwise, how do you explain that people were surprised by > the outcome of the Michelson-Morley experience? it depends on which "people" you are referring to. as i read the history (i'll find the specifics, if you put me on the spot), Einstein knew of the M-M result as was utterly unsurprised. i can't remember the quote, but it was something like "... as if God had any choice in the matter." (i know that Einstein was not a theist in the traditional sense of the word, but used such language to illustrate a point.) if the M-M experiment was not conceived of or performed until 1904, i think that Einstein would have confidently predicted the null outcome. and if it had come out differently Einstein would have been greatly disconcerted and might possibly have challenged the veracity of the non-null result. no outcome of M-M, other than "null", ever made any sense to Einstein. r b-j >>> The constancy of the speed of light in a vacuum is built into Maxwell's >>> Equations. That was known well known at the time; Einstein alludes to that [quoted text clipped - 11 lines] > > See above. The usual 4 Maxwell field equations say nothing of the kind. Assuming that the constitutive relations are independent of reference frame is another story. One can say that classical electrodynamics, as understood post 1908 or so, imply special relativity. For Maxwell's electrodynamics, see below. >> Before Einstein it was believed that the Maxwell eqns >> would hold in their standard form for one priviledged obverser [quoted text clipped - 3 lines] > > I can find no reference that supports this. How about Maxwell's Treatise, with G, the velocity of a point (relative to the ether)? Also, Maxwell's posthumously published letter in Proc. R. Soc. 30, 108, 1880. See also Hertz's theory of electrodynamics in moving media. Modern electrodynamics is not Maxwell's. >> Null results such as Michelson's >> were explained by various ad-hoc assumptions, [quoted text clipped - 3 lines] > to the aether construct. Strangely, after the General Theory of > Relativity, Einstein began thinking about the aether again.[1] Not in England, or in France. Special relativity may well have made the ether unnecessary, but it didn't put an end to it. SignatureTimo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/ E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html > The Maxwell equations say nothing [about constancy of the speed of light]. > They say so -only with the additional assumption- [quoted text clipped - 3 lines] > and what constituted Einstein's fundamental contribution. > (generalised to the relativity postulate) IMHO you got it backwards here. The Principle of Relativity was well established long before Einstein (it dates back to Galileo). Einstein's departure was to consider Maxwell's EQUATIONS to be "laws of physics" in their own right, INDEPENDENT of the aether theory Maxwell used to derive them. Then he applied the PoR to the equations and followed where that led (though his exposition in his 1905 paper is somewhat different). Today this is almost unknown and rarely (if ever) taught in physics courses -- we call them "Maxwell's equations", and not "Maxwell's aether theory", but that's what it was originally. Of course now we also know several derivations of the Maxwell's equations which do not involve an aether, so this is really an aspect of history, not physics. The fact that Einstein's method worked is on the surface quite remarkable (accepting equations while rejecting their derivation via physical arguments), but with today's understanding we know that it happened because of deeper underlying symmetries. It seems that Einstein "lucked out" here, but I think it was rather an aspect of his particular insight and genius. After all, SR was the first major step in the modern era of physics and its emphasis on underlying symmetries. > Before Einstein it was believed that the Maxwell eqns > would hold in their standard form for one priviledged obverser [...] Yes. Because that is now Maxwell obtained them originally. Tom Roberts > "Relativity without tears" can be found herehttp://uk.arxiv.org/abs/0708.0929 > I'll appreciate corrections of English. Other comments are also > welcomed. This thread prompted me to re-publish my old page on "relativity for the 10 years old". http://cc3d.free.fr/Relativity/Relat1.html |
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