From what I understand, the graviton is the particle responsible for the force of gravity. Although this particle has no mass (and is infinite in range), it still must obey the rules of relativity. In that regard, gravitons travel at a finite speed, so there must be a delay between transmission and reception of gravity (i.e. a 1 billion year delay between us and a star 1 billion light years away.
If this idea are true (please tell me if it’s not), then there appears to be a paradox regarding black holes which I don’t understand. A black hole’s escape velocity is greater than the speed of light, thereby capturing everything, including light, that moves into its event horizon. If the escape velocity is greater than that of light, then how do the gravitons escape?
Gravitons are associated with a theory of quantum gravity which doesn’t at present exist, so they are just speculation. Real gravitons, should they exist, would be the quanta of a gravitational wave just as real photons are the quanta of an electromagnetic wave.
Virtual gravitons would be the mediating particle of the gravitational field just as virtual photon are the mediating particle of the EM field. Virtual particles are not constrained to light speed so they could escape from the event horizon of the hole.
Photons can and do get emitted from a black hole… only they’re
infinitely red-shifted to zero frequency, thus, they are effectively
non-existent in all but name.
The graviton, the quanta of the spacetime distortion, is apparently
unaffected by redshift.
I don’t think anyone has seriously looked into a gravitic spectrum
and investigated gravity frequency.