- #36

TerranIV

- 26

- 3

You are missing my point that gravity is SECONDARY. I think the issue is that people are confused what "gravity" means. It is not "a distortion of spacetime", it is not the primary interactions in GR, it is "an attractive force between masses (and equivalent energy)." The spacetime distortions that GR is about (which I consider primary interactions) are not "gravity." Gravity does not accelerate anything, it curves spacetime which changes how momentum is transfered (as well as how time flows locally). GR describes what is "actually" going on, which is a curvature in spacetime (which appear straight in a local frame). As you state, it is momentum that is changing, not some "force at a distance" that needs to be propagated with a graviton.GR does not say that. Perhaps it's how GR is represented in popular literature, but it's not what GR really is. The primary interaction in GR is the interaction between energy-momentum tensor and spacetime metric tensor. The energy-momentum tensor may or may not be associated with mass. The reason why the mass seems essential is because the big massive bodies such as planets and stars usually have more energy-momentum than massless stuff like light. But at the fundamental level, massive electron and massless photon have comparable energies and momenta, so they are equally important in GR.

I'm just confused why anyone thinks that "gravity" would have a boson or a field to parameterize when GR expressly states that gravity is not a real force, and is not why masses (and energy) move through spacetime.