Divine Albert 1911: If clocks OF IDENTICAL CONSTITUTION are used, the
speed of light will not be measured to vary with the gravitational
potential:
http://www.relativitybook.com/resources/Einstein_gravity.html
Albert Einstein 1911: "For if we measure the velocity of light at
different places in the accelerated, gravitation-free system K',
employing clocks U of identical constitution we obtain the same
magnitude at all these places. The same holds good, by our fundamental
assumption, for the system K [a stationary system in a homogeneous
gravitational field] as well."
Divine Albert 1915: If clocks OF IDENTICAL CONSTITUTION are used, the
speed of light will be measured to vary with the gravitational
potential two times faster than the speed of cannonballs:
http://www.speed-light.info/speed_of_light_variable.htm
"Einstein wrote this paper in 1911 in German. It predated the full
formal development of general relativity by about four years. You can
find an English translation of this paper in the Dover book 'The
Principle of Relativity' beginning on page 99; you will find in
section 3 of that paper Einstein's derivation of the variable speed of
light in a gravitational potential, eqn (3). The result is:
c'=c0(1+phi/c^2) where phi is the gravitational potential relative to
the point where the speed of light co is measured......You can find a
more sophisticated derivation later by Einstein (1955) from the full
theory of general relativity in the weak field approximation....For
the 1955 results but not in coordinates see page 93, eqn (6.28):
c(r)=[1+2phi(r)/c^2]c. Namely the 1955 approximation shows a variation
in km/sec twice as much as first predicted in 1911."
http://www.mathpages.com/rr/s6-01/6-01.htm
"Around 1911 Einstein proposed to incorporate gravitation into a
modified version of special relativity by allowing the speed of light
to vary as a scalar from place to place in Euclidean space as a
function of the gravitational potential. This "scalar c field" is
remarkably similar to a simple refractive medium, in which the speed
of light varies as a function of the density. Fermat's principle of
least time can then be applied to define the paths of light rays as
geodesics in the spacetime manifold (as discussed in Section 8.4).
Specifically, Einstein wrote in 1911 that the speed of light at a
place with the gravitational potential phi would be c(1+phi/c^2),
where c is the nominal speed of light in the absence of gravity. In
geometrical units we define c=1, so Einstein's 1911 formula can be
written simply as c'=1+phi. However, this formula for the speed of
light (not to mention this whole approach to gravity) turned out to be
incorrect, as Einstein realized during the years leading up to 1915
and the completion of the general theory. (...) ...we have c_r
=1+2phi, which corresponds to Einstein's 1911 equation, except that we
have a factor of 2 instead of 1 on the potential term."
The truth: If clocks OF IDENTICAL CONSTITUTION are used, the speed of
light will be measured to vary with the gravitational potential
exactly as the speed of cannonballs does. The variation obeys the
equation c'=c(1+phi/c^2) given by Newton's emission theory of light.
Pentcho Valev
pva...@yahoo.com