We’re now in a position to discuss tests of relativity more quantitatively. One such test is that relativity requires the speed of light to be the same in all frames of reference, for the following re...We’re now in a position to discuss tests of relativity more quantitatively. One such test is that relativity requires the speed of light to be the same in all frames of reference, for the following reasons. There are two types of tests we could do: (1) test whether photons of all energies travel at the same speed, i.e., whether the vacuum is dispersive; (2) test whether observers in all frames of reference measure the same speed of light.
