On 24 Jul, 08:31, Pentcho Valev <pva...@yahoo.com> wrote:

Einstein offered two equations showing how the speed of photons moving
radially with respect to a spherical mass varies with the
gravitational potential V:

(A) c' = c(1 + V/c^2)

(B) c' = c(1 + 2V/c^2)

(seehttp://www.mathpages.com/rr/s6-01/6-01.htm)

Equation A is consistent with the Pound-Rebka experiment and also
(through the application of Einstein's equivalence principle) with the
equation c'=c+v given by Newton's emission theory of light (v is the
speed of the light source relative to the observer). It is not clear
what equation B is consistent with.

Pentcho Valev
pva...@yahoo.com

Ah, velocity relative to source. Could you explain to me how it is
possible to see double stars. I must say my profile was designed for
textural analysis rather than Relativity. It will serve though.