Do Gravitons Exist?

[Alex K]

I was thinking some intensely energetic gravitons were generated in the BB. And in our era they would be disorganized like static on an analog radio, IOW everywhere.

Not sure why I was thinking they were 'immune' to losing energy due to the expansion of the universe, the wavelengths would be getting longer as space dilutes them like photons.


Well, try this;

initial energies of photons in the BB would have been high, but the universe was opaque to them for quite a while, so the initial high energy ones would have been subject to scattering absorption/reabsorption by subatomic particles and hydrogen. this would be an additional loss of energy over and above the expansion of the universe effect.

Would gravitons have been as effectively attenuated in the early stages of the BB as photons were, and subsequently would still be 'potent' after cosmic expansion ?

See, photons had to go through 2 'gauntlets'. Gravitons less, maybe substantially less than 2 but more than 1.

Gravitons from the BB would have been redshifted like photons. One way to see them would have been the so-called tensor fluctuations of the cosmic microwave background which the BICEP2 experiment claimed to have detected and then retracted a couple of years ago. Those would have been traces of quantum fluctuations of spacetime and the best indirect evidence that gravitons exist...