please delete the Xposts to *french* newsgroups.

thanks, colleagues !


Pentcho Valev a écrit :
On Mar 8, 1:37 pm, Pentcho Valev <pva...@xxxxxxxxx> wrote:
Einsteinians Richard Epp and Robert Myers: "Our universe has a split

Generally the schizophrenic universe teaches Einsteinians how to
fiercely fight Newton's emission theory of light, but sometimes it
tells them to do the opposite. They obey and even go as far as to
rediscover the forbidden 18th century optics:
John Stachel: "The idea that a light beam consisted of a stream of
particles had been espoused by Newton and maintained its popularity
into the middle of the 19th century. It was called the "emission
theory" of light, a phrase I shall use. The need to explain the
phenomena of interference, diffraction and polarization of light
gradually led physicists to abandon the emission theory in favor of
the competing wave theory, previously its less-favored rival.
Maxwell's explanation of light as a type of electromagnetic wave
seemed to end the controversy with a definitive victory of the wave
theory. However, if Einstein was right (as events slowly proved he
was) the story must be much more complicated. Einstein was aware of
the difficulties with Maxwell's theory-and of the need for what we now
call a quantum theory of electromagnetic radiation-well before
publishing his SRT paper. He regarded Maxwell's equations as some sort
of statistical average-of what he did not know, of course-which worked
very well to explain many optical phenomena, but could not be used to
explain all the interactions of light and matter. A notable feature of
his first light quantum paper is that it almost completely avoids
mention of the ether, even in discussing Maxwell's theory. Giving up
the ether concept allowed Einstein to envisage the possibility that a
beam of light was "an independent structure," as he put it a few years
later, "which is radiated by the light source, just as in Newton's
emission theory of light."......If we model a beam of light as a
stream of particles, the two principles can still be obeyed. A few
years later (1909), Einstein first publicly expressed the view that an
adequate future theory of light would have to be some sort of fusion
of the wave and emission theories. This is an example of how the
special theory of relativity functioned as a theory of principle,
limiting but not fixing the choice of a constructive theory of light."
John Stachel: "As a theory of principle (see above), the theory of
relativity provides important guidelines in the search for such a
satisfactory theory. Einstein anticipated the ultimate construction of
"a complete worldview that is in accord with the principle of
relativity."[25] In the meantime, the theory offered clues to the
construction of such a worldview. One clue concerns the structure of
electromagnetic radiation. Not only is the theory compatible with an
emission theory of radiation, since it implies that the velocity of
light is always the same relative to its source; the theory also
requires that radiation transfer mass between an emitter and an
absorber, reinforcing Einstein's light quantum hypothesis that
radiation manifests a particulate structure under certain
circumstances. He maintained that "the next phase in the development
of theoretical physics will bring us a theory of light, which may be
regarded as a sort of fusion of the undulatory and emission theories
of light."
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¸cois 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

Pentcho Valev

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