I'd like to point out light's mass/energy isn't in its motion. If it was all light would have the same mass since all light moves at the same speed.
The mass of the photon is equivalent to the energy that is defined by the wave.
Author:
Light is massless.
Due to my new work on light expansion I now believe light is massless. Light expands from mass as a wave of EM energy that spreads out and when is absorbed must collapse back to mass. The process of light expansion or inflation turns mass into massless light and the collapse of light's wave turns it back into matter or mass at absorption.
If mass is concentrated energy as it would have to be in Einstein's definition of mass then spread out light waves can't be mass. They go back to being mass only in an electromagnetic wave collapse at absorption. Waves are large PACKETS according to Einstein's interpretation of his Photoelectric Effect. And as I have pointed out they can be very very large creating the noticable effect of expanding light or light growing to size. This takes time. Light waves take time to form fully.
Nick
Author: Nick
My prediction stands. Light is an unconcentrated form of mass/energy unlike matter.
The mass/energy is in the wave and the wave is relative.