Re: How Einstein's dead wrong, relatively speaking
As seen from the perspective of a frame of reference that is co-rotating with the platform the light beams do travel the same distance. The result of the Sagnac experiment has been cited by many as a disproof of the theory of relativity, starting with Ives in 1938. The reasoning is that if the speed of light is a constant for the observer, then for the observer on the rotating ring light should take the same time to travel each way and no effect should occur. This argument does not hold because the rotating ring is an accelerated frame of reference, while the constancy of the speed of light (c) applies only in inertial frames of reference.