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Article #642Re: HOW EINSTEIN USED MAXWELL
From: xxein
Date: Sat, 03 Apr 2010 23:25
Date: Sat, 03 Apr 2010 23:25
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7678 bytes
On Apr 1, 5:18 am, Pentcho Valev <pva...@yahoo.com> wrote: > According to Maxwell's theory, (1) the speed of light is independent > of the speed of the emitter but (2) it does depend on the speed of the > observer: > > http://www.pitt.edu/~jdnorton/papers/companion.doc > John Norton: "Einstein's second postulate, the light postulate, > asserts that "light is always propagated in empty space with a > definite velocity c which is independent of the state of motion of the > emitting body." Einstein gave no justification for this postulate in > the introduction to his paper. Its strongest justification came from > Maxwell's electrodynamics. That theory had identified light with waves > propagating in an electromagnetic field and concluded that just one > speed was possible for them in empty space, c = 300,000 km/sec, no > matter what the motion of the emitter." > > http://www.futura-sciences.com/fr/doc/t/physique/d/relativite-restrei... > "Les équations de Maxwell prévoyaient la propagation de la lumière à > la vitesse de 300.000 km/s par rapport à l'éther. Or, si l'on cherche > à calculer la vitesse de la lumière par rapport à un référentiel qui > est lui-même mobile dans l'éther, on observe que la lumière se propage > avec une vitesse différente..." > > http://www.solidarity-us.org/node/58 > "Maxwell's theory of electricity and magnetism provides a successful > framework with which to study light. In this theory light is an > electromagnetic wave. Using Maxwell's equations one can compute the > speed of light. One finds that the speed of light is 300,000,000 > meters (186,000 miles) per second. The question arises: which inertial > observer is this speed of light relative to? As in the previous > paragraph, two inertial observers traveling relative to each other > should observe DIFFERENT SPEEDS FOR THE SAME LIGHT WAVE." > > In 1905 Einstein adopted the former assertion of Maxwell's theory (the > speed of light is independent of the speed of the emitter) and, by > applying the principle of relativity, inferred that the speed of light > is independent of the speed of the observer as well. > > Einstein could have adopted the latter assertion of Maxwell's theory > (the speed of light does depend on the speed of the observer). Then, > by applying the principle of relativity, he would have inferred that > the speed of light does depend on the speed of the emitter as well. > This would have been a return to Newton's emission theory of light: > > http://www.mfo.de/programme/schedule/2006/08c/OWR_2006_10.pdf > Jean Eisenstaedt: "At the end of the 18th century, a natural extension > of Newton's dynamics to light was developed but immediately forgotten. > A body of works completed the Principia with a relativistic optics of > moving bodies, the discovery of the Doppler-Fizeau effect some sixty > years before Doppler, and many other effects and ideas which represent > a fascinating preamble to Einstein relativities. It was simply > supposed that 'a body-light', as Newton named it, was subject to the > whole dynamics of the Principia in much the same way as were material > particles; thus it was subject to the Galilean relativity and its > velocity was supposed to be variable. Of course it was subject to the > short range 'refringent' force of the corpuscular theory of light -- > which is part of the Principia-- but also to the long range force of > gravitation which induces Newton's theory of gravitation. The fact > that the 'mass' of a corpuscle of light was not known did not > constitute a problem since it does not appear in the Newtonian (or > Einsteinian) equations of motion. It was precisely what John Michell > (1724-1793), Robert Blair (1748-1828), Johann G. von Soldner > (1776-1833) and François Arago (1786-1853) were to do at the end of > the 18th century and the beginning the 19th century in the context of > Newton's dynamics. Actually this 'completed' Newtonian theory of light > and material corpuscle seems to have been implicitly accepted at the > time. In such a Newtonian context, not only Soldner's calculation of > the deviation of light in a gravitational field was understood, but > also dark bodies (cousins of black holes). A natural (Galilean and > thus relativistic) optics of moving bodies was also developed which > easily explained aberration and implied as well the essence of what we > call today the Doppler effect. Moreover, at the same time the > structure of -- but also the questions raised by-- the Michelson > experiment was understood. Most of this corpus has long been > forgotten. The Michell-Blair-Arago effect, prior to Doppler's effect, > is entirely unknown to physicists and historians. As to the influence > of gravitation on light, the story was very superficially known but > had never been studied in any detail. Moreover, the existence of a > theory dealing with light, relativity and gravitation, embedded in > Newton's Principia was completely ignored by physicists and by > historians as well. But it was a simple and natural way to deal with > the question of light, relativity (and gravitation) in a Newtonian > context." > > http://ustl1.univ-lille1.fr/culture/publication/lna/detail/lna40/pgs/... > Jean Eisenstaedt: "Même s'il était conscient de l'intérêt de la > théorie de l'émission, Einstein n'a pas pris le chemin, totalement > oublié, de Michell, de Blair, des Principia en somme. Le contexte de > découverte de la relativité ignorera le XVIIIème siècle et ses racines > historiques plongent au coeur du XIXème siècle. Arago, Fresnel, > Fizeau, Maxwell, Mascart, Michelson, Poincaré, Lorentz en furent les > principaux acteurs et l'optique ondulatoire le cadre dans lequel ces > questions sont posées. Pourtant, au plan des structures physiques, > l'optique relativiste des corps en mouvement de cette fin du XVIIIème > est infiniment plus intéressante - et plus utile pédagogiquement - que > le long cheminement qu'a imposé l'éther." > > Pentcho Valev > pva...@yahoo.com xxein: No physicists here. Just a bunch of taught wannabees.
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X-Google-Thread: fa4c1,e17dad18d26e7f0c X-Google-NewGroupId: yes X-Google-Thread: 111645,e17dad18d26e7f0c X-Google-NewGroupId: yes X-Google-Attributes: gid2479375fed,gid237b8ad48,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII Path: arc1-ca.pugleaf.net!g2news2.google.com!postnews.google.com!z3g2000yqz.googlegroups.com!not-for-mail From: xxein <xxein@comcast.net> Newsgroups: sci.physics.relativity,sci.physics,fr.sci.physique,fr.sci.astrophysique Subject: Re: HOW EINSTEIN USED MAXWELL Date: Sat, 3 Apr 2010 16:25:31 -0700 (PDT) Organization: http://groups.google.com Lines: 106 Message-ID: <ff57573b-db58-4185-8d1c-3886f78919c0@z3g2000yqz.googlegroups.com> References: <1e43f6e3-a9d5-4f43-8c87-64ada4cc4f7d@r18g2000yqd.googlegroups.com> NNTP-Posting-Host: 76.110.147.115 Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: posting.google.com 1270337132 2511 127.0.0.1 (3 Apr 2010 23:25:32 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Sat, 3 Apr 2010 23:25:32 +0000 (UTC) Complaints-To: groups-abuse@google.com Injection-Info: z3g2000yqz.googlegroups.com; posting-host=76.110.147.115; posting-account=0hs16QoAAACtAk44qiyJw2TmTxN8_NXm User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; GTB6.4; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.0.04506; AskTB5.6),gzip(gfe)