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Comment by mati365 | Hacker News Reader

Isn't space gravity carrier itself? Something like the water that has waves?

I believe they're referring to the idea of a gravitational force carrying particle, like photons for electromagnetism, W/Z bosons for the weak force, and gluons for the strong force. Typically this gets called a graviton but they've never been observed and the theories predicting them as far as I know don't predict that we can detect them in any meaningful/practical way right now which is also one of the problems for issues with a quantum theory of gravity.

I've always wondered (but not done the research/reading) on how that would mesh with black holes since you'd need gravitons to escape to mediate the curvature of space-time but that'd seemingly (to me) require them to be able to either ignore the curvature of space-time or travel faster than the speed of light in order to do so. And I believe that those two options there are actually mathematically equivalent as far as the consequences of things go.

This question isn’t actually anything to do with quantum mechanics. One can already ask, for GR, can a gravity wave generated by a wiggling object that has already passed the event horizon propagate back out through the event horizon? The answer from gr is unambiguously no. Effectively, all complicated goings-on inside the black hole are washed out into just a couple parameters for an outside observer: total mass, total charge, total angular momentum. All the matter contained by the black hole does still make its gravitational effect felt on outside objects through these three parameters.

This observation in fact is what inspired wheeler to ask his grad student bekenstein what then happens to the entropy of a cup of tea thrown into the black hole — how to reconcile with 2nd law of thermo. Which in turn was the start of the very long story of black hole thermodynamics.

That would suggest space is "made of" something, so what would that be? If it's made of something, how is that "carrying" the wave, causing it to distort in the presence of mass?

Or that gravity is made of something traveling through the

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