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Replies: 5   Last Post: Mar 9, 2013 1:05 PM

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Pentcho Valev

Posts: 6,212
Registered: 12/13/04
Posted: Mar 9, 2013 1:05 PM
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The Curious History of Relativity: How Einstein's Theory of Gravity Was Lost and Found Again, Jean Eisenstaedt, pp. 17-19: "If, as Michelson's experiments showed, this theorem of the addition of speeds is not valid, in particular for light, then something is not right with our initial assumptions. (...) The most convincing solution physicists will find will be special relativity. Not much will remain of our initial hypotheses: neither Newton's absolute time nor the definition of speed will survive. But, above all, in this new kinematics a new physical constant will appear, c. It will no longer be possible to add two speeds without the intervention of c. No kinematics will be possible without c; no physics will be possible without c."

No physics at all without c? Why are Einsteinians so adamant, Jean Eisenstaedt? Because that's the way ahah ahah they like it, ahah ahah?

Physics "without c" is called Newton's emission theory of light. Is it correct, Jean Eisenstaedt?
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."
Einstein and the Changing Worldviews of Physics, Einstein Studies, 2012, Volume 12, Part 1, 23-37, The Newtonian Theory of Light Propagation, Jean Eisenstaedt: "It is generally thought that light propagation cannot be treated in the framework of Newtonian dynamics. However, at the end of the 18th century and in the context of Newton's Principia, several papers, published and unpublished, offered a new and important corpus that represents a detailed application of Newton's dynamics to light. In it, light was treated in precisely the same way as material particles. This most interesting application - foreshadowed by Newton himself in the Principia - constitutes a relativistic optics of moving bodies, of course based on what we nowadays refer to as Galilean relativity, and offers a most instructive Newtonian analogy to Einsteinian special and general relativity (Eisenstaedt, 2005a; 2005b). These several papers, effects, experiments, and interpretations constitute the Newtonian theory of light propagation. I will argue in this paper, however, that this Newtonian theory of light propagation has deep parallels with some elements of 19th century physics (aberration, the Doppler effect) as well as with an important part of 20th century relativity (the optics of moving bodies, the Michelson experiment, the deflection of light in a gravitational field, black holes, the gravitational Doppler effect). (...) Not so surprisingly, neither the possibility of a Newtonian optics of moving bodies nor that of a Newtonian gravitational theory of light has been easily "seen," neither by relativists nor by historians of physics; most probably the "taken-for-granted fact" of the constancy of the velocity of light did not allow thinking in Newtonian terms."

Pentcho Valev

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