If light approaches a black hole will it accelerate? I think this question ties in with whether light has mass or not. Does light have mass? It seems accepted that light has momentum, but this is not consistent with saying that photons are mass-less (momentum=mass*volume). Could someone clear this up or is it actually a contradiction? Mass is a requirement for gravity also. I've always heard that not even light can escape a black hole which is gravitational force, so wouldn't a black hole have enough force to accelerate light?