Well, I will give one more reply. You suggested that light travels at different speeds, using a diagram to show it. Your diagram doesn't show anything of the sort. It is the same thing that Michelson-Morley experiment tested for and it was found that it didn't happen. If you measure the speed of light in the frame of reference of the source it will be found to be C. If you measure the speed of light from that source in any other reference frame it will be found to be C. The frequency of the light will be different, but there will be no change in speed. This applies whether the two frames are moving with respect to each other or if they are in locations where the spacetime is warped differently (that is they are in places where the gravitational field is different). Since they are in different reference frames their clocks and other measuring tools will give different results, because of the effects of relativity. The tools will still be completely accurate in their own reference frame, it is just that in comparing them between different reference frames they will appear to be different.

The predictions of relativity, both SR and GR, have been tested to very high accuracy and they have so far been found to be correct. And in none of the tests has there been found any indication that C changes under any conditions. If you can't believe that I suggest that you get a good book on relativity and study up on it.

Bill Gill

C is not the speed of light in a vacuum.
C is the universal speed limit.