How do gravitons escape from black holes?

Answer 1

It's safe to assume gravitons, if they exist, don't escape from black holes, or at least, do not escape directly; but this does raise the interesting question as to how mass can interact with other mass if one of them is "hidden" behind an event horizon - could a force-carrier, including a force-carrier particle for gravity escape "outwards" through the event horizon. Gravitons remain in the theoretical realm, and only a few of their properties can be presumed, such as their class, their spin, and their mass (zero). If they are fit into the standard model it will require a theory of quantum gravity, particularly to resolve differences between known properties of the current standard model, since gravitons likely would require the background independence considered fundamental to general relativity. Until that time, general relativity, which proposes that matter affects space and the gravity is a component of spacetime (in other words, gravitation reflects a curvature in spacetime) might provide the most accurate description of how mass 'behind' the event horizon can affect matter outside it, and thus could obviate questions about force-carrier mediations relating to mass.

Quantum effects could in theory support models of particle interactions of the gravity force carrier near the event horizon, based on similar theories consistent with quantum mechanics; Hawking radiation for example has been explained by fluctuations in spacetime boosted by gravity causing virtual particles located just outside the event horizon to become real, and thus allowing mass within the black hole to be 'carried away'; another theory posits that particles can escape from just inside the event horizon by exploiting tunneling (or quantum nonlocality) to 'escape.'

Until gravitons are more fully described (or detected and their existence proven) the question itself could be shown to presume facts not in evidence and/or that theories describing the method of their escape from a black hole should be considered speculative.