The Speed Limit
Review of the idea that nothing can travel faster than the speed of light .
The example below shows directly, from the principle of relativity, that c is the ultimate speed limit.
- (This is a version of the example from the text, page 108.)
- Light pulses (A & B) are emitted at O, travel to mirrors, are reflected and return to O.
- Now suppose O is moving (with respect to us) to the right at a speed which is greater than the speed of light. What do we see?
- We see pulse B never returns to O!! After pulse reflects from the mirror, we see it move at the speed of light which would be less than the speed with which O is moving ? B will never catch up to O!
- Whether B returns to O or not cannot depend on the reference frame. Therefore, O cannot move at speeds greater than light!!