Originally Posted by PhoenixFire
I was trying to explain to my Dad today what E=MC^2 actually meant, but soon realised that I didn't actually know enough about it to explain it in a reasonable manner. Could someone (SS/Spark most likely) explain what it actually means.
The principle of relativity/constancy of the speed of light (that's the crazy part) has odd consequences for the energy of light as viewed in different inertial reference frames. The connection to mass comes from looking at the change in energy of a stationary vs moving particle before and after emitting said light.
were originally written up by some patent clerk in Bern.