I don’t think there’s any evidence for gravitons yet, and gravity hasn’t been quantized. I’d say it’s this similarity that’s the best argument of quantum gravity, not the other way around.
Fair. The masslessness of the bosons that should mediate gravity, along with them being spin-2, can however be deduced from the properties of gravitational waves.
We know that gravity is a wave that travels at the speed of light, this has been experimentally measured many times. If it is also quantized (a very reasonable symptom hypothesis since everything else that we’ve ever seen is) then by definition there are particles that carry gravity.
If gravity is continuous then we would end up with something like the ultraviolet catastrophe but for gravity.
Hmm, I hadn’t considered an “ultragravity catastrophe”. I wonder if this could accout for dark energy or the supposed inflatons? Probably not, the catastrophe suggests infinite energy, not just lots of energy, eh?
The ultraviolet catastrophe was averted due to the discreet nature of electrons though, and I don’t recall gravity behaving as a blackbody radiator anyway. Would this come into effect at horizons?
