Orac, I haven't had time to follow those links yet, but I would like to check that I am on the right path. I never think I understand something unless I can explain to someone else; so please bear with my attempt.
I gravitons exist, this would seem to indicate that a quantum theory of gravity is, in principle, a distinct possibility in the near future. However, it is experimentally established (and experiment trumps theory) that gravity creates more gravity, which presents a couple of serious questions.
1. If gravity creates gravity, why doesn’t every gravitating body spontaneously develop into a black hole?
2. Can the introduction of gravitons to our theory of gravity provide an answer to Q1?
A graviton can “split” into gravitons of lower energy, but a graviton cannot produce another graviton of any energy if the total energy is greater after the reaction than it was before, as this would involve creating energy.
Certainly this would prevent run-away gravity, but it would also prevent quantized gravity from producing more gravity, which, as we have seen, would be contrary to physical evidence.
It follows, therefore, that if gravity creates gravity, gravitons cannot play a part in this process without violating the law of conservation of energy.
