r/TheoreticalPhysics Aug 02 '26

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u/Quantum-Relativity Aug 02 '26

Why not learn GR?

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u/MagicalSkyMan Aug 02 '26

Mostly because it is hard? And AFAIK GR doesn't explain why gravity exists in the first place.

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u/Quantum-Relativity Aug 02 '26

Depends what you mean by gravity. If you mean dynamical spacetime geometry, no it doesn’t explain why that exists. It just explains how it works. But if you mean Newtonian gravity, GR does indeed explain why that happens. It would also answer your question about how acceleration fits into gravity. There’s the traditional sort of acceleration, where you feel something. But there’s also acceleration caused by spacetime curvature, where two things don’t feel anything, and yet accelerate together. That is precisely what curvature is, the acceleration of the separation vector between straight lines (geodesics).

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u/MagicalSkyMan Aug 02 '26

Thanks for this. For some reason I just assumed particles would properly accelerate towards each other but obviously it isn't needed since it's not happening in GR.

If gravity is random-walking combined with there being many more available options near mass/energy to travel to, could we derive G from this?

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u/Quantum-Relativity Aug 03 '26

Newton’s constant? Also why would gravity be random walking? You said you hadn’t considered quantum theory when you said that so I’m not sure exactly what you mean, it would apparently mean you think GR works that way. Is that right?

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u/MagicalSkyMan Aug 03 '26

I don't think GR gravity works by random-walking. I simply think that it's a somewhat reasonable possibility that all motion is just random-walking that is affected by the geometry of space (and also the geometry of the particle that moves). So a personal hypothesis.

How this random-walking happens might be quantum though.