Why does light have a maximum speed?

Answer 1

Answer:

well, that's a very good question.

It would seem that the speed of light is more: its the maximum speed which energy can travel through space. They used to believe light travels as waves through an invisible medium that fills space (like water waves travel through water). If this was true, then light being shot off the planet in the opposite direction to its spin should have appeared to travel faster than the light that was shot in the same direction of the earth's spin. Imagine you sat at the front of a speed boat doing 5mph, then made some waves, you can picture that those waves would not go away from you as fast as the waves you made when sitting at the back of the boat? This was not the case with light, and so there was no medium (or ether, as it was known)!

So why is the speed of light as it is? we don't know, but what we do know is there is a clever link somewhere, because if you do a nuclear reaction, conservation of energy and mess are tidily represented via E=MC^2, and guess what? C= the speed of light! In other words, if you do a nuclear reaction and you lose some mass, because it was changed into energy (this is what a nuclear reaction is), then you use this equation to work out how much energy has been made from the mass that has been lost.