Common thinking is that Photons or EM waves have no mass and are therefore not effected by gravity. Yet, E=MC2 suggests that they should have a mass as they are packets of energy. Could it be that they indeed do have an extremely small mass, but that the effect of "gravity" on them is cancelled by the constant reversal of electrical and magnetic field associated with them as they travel through space? Einstein describes gravity as a distortion of space-time. Perhaps changing electrical and magnetic fields within space-time can have an effect on the perceived force of "gravity". Any thoughts?