I couldn't help but notice the discussions concerning the speed of
light, and I just have to step into this one.
As far as I am concerned the speed of light is constant. Maxwell came to
the same conclusion when he discovered that the speed of an EM wave was
related to the (permeability of free space) and the (permittivity of
free space) given by:
c = 1/sqrt[(permeability of free space)*(permittivity of free space)]
Which is a constant due to the very nature of space itself. Thus,
Einstein's postulate that the speed of light is the same in all
reference frames would be correct, sense, the space in all reference
frames is the same.
The only way that the speed of light could change is if one or both of
the constants above were altered by some special process.
Terry