Comment Re:Fun with Google -- Incorrect (Score 2, Informative) 205
Weight, which is a Newtonian concept, is not really applicable to an inherently relativistic particle such as the photon. In addition, the effect of gravity on a photon is actually about twice as large as you would expect from Newtonian gravitation. This comes from the weak-field limit of general relativity, and was one of the first tests of the theory. In 1919, Sir Arthur Eddington observed the bending of starlight around the sun during a solar eclipse, and showed that the bending was, lo and behold, about twice as large as the Newtonian prediction, and consistent with general relativity.