Does gravity affect light and does it have mass?
Yes, gravity affects light. Light bends towards a massive body and deviates from its path. The velocity of light changes in the sense that its direction changes. (Expt of Sir Aurthur Eddington) Locally the speed of light remains const as demanded by SR. But for the observer located on the massive body, light going away from it appears to be slowed down and the opposite is also true. (This has been observed in what is called The Shapiro Delay) I think light does have some relativistic mass (rest mass=0) as according to the mass-energy relation. So, it is affected by gravity. Space-time affected by gravity, affects light. The relativistic mass of light responds to the gravitational field. The above statements are equivalent. >>>I’m not sure about the mass, as it is still being researched.
