If a photon has mass then it can't possibly reach the speed of light, but if a photon is massless then it can't be affected by gravitational fields, and surely in reality, it is affected. The way I see it, if a photon has 0 mass, then not even the mightiest of black holes can affect it's course..
One argument could be that the photon just transports mass from place to place, while not actually having the effects on itself. But, saying that theres no effect on the photon by the mass it carries, is like saying that the photon is not a player in the gravity game.
Ofcourse this is a paradox.. And I'm probably missing something.
Anyone?