Can Gravitons Escape Black Holes?

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Discussion Overview

The discussion revolves around the question of whether gravitons, if they exist as massless particles traveling at the speed of light, can escape from black holes. Participants explore concepts related to gravitational field theory, quantum gravity, and the behavior of particles near black holes.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants question how gravitons could escape a black hole, given their assumed properties of being massless and traveling at the speed of light.
  • Others suggest that the explanation may lie within gravitational field theory, which some participants admit they have yet to learn.
  • One participant draws a parallel between the behavior of gravitons and virtual photons, suggesting that both may relate to the uncertainty principle.
  • A participant proposes that a distant observer would never actually witness a black hole forming, instead seeing matter falling inward more slowly, which might imply that gravitational waves emitted before reaching the Schwarzschild radius could escape.
  • There is a discussion about the compatibility of quantum gravity with field theory, with some participants expressing confusion over the relationship between quantized radiation and field theory.

Areas of Agreement / Disagreement

Participants express various viewpoints on the nature of gravitons and their interaction with black holes, with no consensus reached on the explanations or implications of these ideas. The discussion remains unresolved with competing perspectives on gravitational field theory and quantum gravity.

Contextual Notes

Some limitations include the dependence on the assumptions about the existence of gravitons and the nature of quantum gravity, as well as the unresolved details regarding gravitational wave production and the implications of the uncertainty principle.

cgw
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Maybe a simple or stupid question so bear with me (it is late and I just thought of this). Assuming the existence of gravitons and assuming they are mass-less and travel the speed of light - how can they escape a black hole? Please point me in the right direction.
 
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I've always wondered that myself. I figured it is explained by gravitational field theory, which I have yet to learn.
 
I've wondered about this too. I've also wondered about why charged particles don't "glow" with virtual photons (my nuclear physics professor told me once, but I forgot the explanation). I think the answer to these two questions might be the same. I think this might have something to do with the uncertainty principle.
 
For the gravity case, here's a thought: a distant observer never actually sees a black hole form. The observer would just see a shell of matter falling inward more and more slowly, asymptotically approaching the Schwarzschild radius as time goes on. So if I'm interpreting this right, you could say that all the gravitational waves that are ever going to escape from the black hole's gravity well are emitted in the "short time" it takes for the infalling matter to reach r = 2M.

Right now I'm wishing I hadn't missed a lecture on gravitational wave production a few weeks ago... :-(
 
Troponin said:
I've always wondered that myself. I figured it is explained by gravitational field theory, which I have yet to learn.
It is. But a quantum theory of gravity, by definition, is - well - quantized, which means it is incompatible with a field theory of gravity.
 
DaveC426913 said:
It is. But a quantum theory of gravity, by definition, is - well - quantized, which means it is incompatible with a field theory of gravity.

Not sure I get this. Elect-mag radiation is quantized and is compatable with field theory. Right?
 

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