I'm sure this is a very newbie-level question, but how is it that massless particles and light are affected by gravity? I've been reading about the 'ghost condensate' theory, and the latest article in New Scientist that says these massless 'ghost' particles should have been sucked up by black...
Where does the speed of light (~300000km/sec in vacuum) come from
Is this the rotational speed of an electron. Up to Einstein a photon has no mass once it is in movement.
Is the absence of mass the reason why speed of light cannot be modified ?