[Raapys]

I don't know, I still don't see how gravity and magnetism are *not* infinite sources of energy. They can both definitely apply kinetic energy to other masses, and to our knowledge they do not weaken over time, indicating they are inexhaustible.

Photons are a special case, aren't they? Since they can, apparantly, be slowed down by passing through certain matter, then speed up again entirely by themselves.