'nothing, not even light'

[Duke of Gloucester]

From what I know light doesn't have a mass but does act as it had one in several aspects. If light does have mass, then the Theory of Relativity says that this mass is unlimited and that would create a huge black hole that consumes the hole universe.

Light does have mass. The mass of a given photon is hf/c^2 where h is Plancks constant, c is the speed of light and f is the frequency of the photon. E=mc^2 tells us that mass and energy are basically the same thing, and since photons have energy, they must have mass.

The equipment Ronin describes is called a Crooke's radiometer, but in spite of what some school teachers tell you, it does not rotate because it is being knocked by photons. It rotates because the black sides are hotter than the silver sides. See the link:
http://www.physics.brown.edu/physics...emo/4d2010.htm