The Time Illusion (Kindle Single)

by John Gribbin

The number which matched the speed of light was indeed ‘a’ constant, which became represented by the letter c. The equations seemed to be saying that the speed of light is always the same, wherever you measure it from. And this conflicts with classical mechanics. If you were moving towards a light source (a lamp, or a star, or any source of light) at a speed of 50 km per hour you would expect to measure the speed of the light coming towards you as c + 50 km/hr. If the light was coming from behind you, overtaking you as you moved away from the lamp, you would expect to measure its speed as c - 50 km/hr. But Maxwell’s equations make no allowance for this. They just say that if you measure the speed of light the answer you get will be c, regardless of where the light is coming from, or how you are moving relative to the light source.