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From: John Jones on 4 Apr 2010 19:48
Pentcho Valev 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-restreinte-et-naissance-de-lespace-temps_509/c3/221/p5/
> "Les �quations de Maxwell pr�voyaient la propagation de la lumi�re �
> la vitesse de 300.000 km/s par rapport � l'�ther. Or, si l'on cherche
> � calculer la vitesse de la lumi�re par rapport � un r�f�rentiel qui
> est lui-m�me mobile dans l'�ther, on observe que la lumi�re se propage
> avec une vitesse diff�rente..."
>
> 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 Fran�ois 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/4_5.pdf
> Jean Eisenstaedt: "M�me s'il �tait conscient de l'int�r�t de la
> th�orie de l'�mission, Einstein n'a pas pris le chemin, totalement
> oubli�, de Michell, de Blair, des Principia en somme. Le contexte de
> d�couverte de la relativit� ignorera le XVIII�me si�cle et ses racines
> historiques plongent au coeur du XIX�me si�cle. Arago, Fresnel,
> Fizeau, Maxwell, Mascart, Michelson, Poincar�, Lorentz en furent les
> principaux acteurs et l'optique ondulatoire le cadre dans lequel ces
> questions sont pos�es. Pourtant, au plan des structures physiques,
> l'optique relativiste des corps en mouvement de cette fin du XVIII�me
> est infiniment plus int�ressante - et plus utile p�dagogiquement - que
> le long cheminement qu'a impos� l'�ther."
>
> Pentcho Valev
> pvalev(a)yahoo.com
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