I believe that there are no "gravitons". A mass warps SpaceTime. Anything moving past the mass has it's direction changed by that warping not by the mass. "Freeze" SpaceTime & remove the mass & it's "gravity" and things will still follow the same warped path. Therefore, there is no "force of gravity."
1 Answers
We do not know if there are gravitons. There is no experiment that would prove their existence.
Theoretically, it is a good idea to learn about EM forces, and their carriers, the photons. The mediator of EM forces is the photon. Two particles can have EM interaction by exchanging photons.
Photons do not have rest mass, just like gravitons. That explains the long range of both EM and gravitational forces. The same way the mediator of gravitational effects is the graviton. Two particles can have gravitational interaction by exchanging gravitons.
It is not mass but stress-energy that causes gravity. This way, even particles, like the photon, that have no rest mass, can have gravitational effects.
When stress-energy bends spacetime, that is an effect of gravity. You are right that when a photon travels past the Sun, it travels in bent spacetime (because of the Sun's stress-energy).
Even the Earth orbits the Sun in bent spacetime, because of the Sun's stress-energy.
Gravitons, just like photons, travel with speed c in vacuum, when measured locally. Both EM waves and gravitational waves travel at this speed. If you remove the Sun, the Earth would still move along the bent spacetime orbiting the Sun (even if the Sun is not there anymore) for another 8 minutes. After 8 minutes, the effects of gravity from the Sun's stress-energy disappear, and the Earth starts to move out of the solar system.
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