ABSTRACT
According to Newtonian mechanics, if light has a velocity of c relative to a frame at absolute rest (That the notion of a frame at absolute rest is valid is one of the postulates of Newtonian mechanics, it is not there in Einstein’s postulates of special relativity) and if a person carrying a torch moves with velocity v relative to a frame K at absolute rest, then the speed of light will be c+v relative to K. This is a contradiction if we assume Maxwell’s theory of electromagnetism to be correct in all inertial frames, for Maxwell’s theory then predicts the same speed c of light in all inertial frames. We should note that according to Ernst Mach, there exists a frame at absolute rest and any frame that is in uniform motion relative to this frame should be regarded as an inertial frame an no other. Such a frame at absolute rest is a frame that is non-moving relative to the distant stars and galaxies in the universe and is at infinite distance from all such matter. This notion was used by Einstein in his general relativity theory but not in his special relativity theory. Einstein assumed that Maxwell was right and Newton was not right and this led him to postulate two principles for the special theory of relativity which would modify Newtonian mechanics. These postulates were:
The velocity of light is the same in all inertial frames in vacuum.
The laws of physics are the same in two frames that are at uniform motion relative to each other.
