Gravity & Force From Black Holes: How Do Photons Escape?

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Discussion Overview

The discussion revolves around the nature of black holes and their interaction with photons, particularly in the context of electromagnetic forces and gravity. Participants explore the implications of charged black holes and the behavior of photons and virtual photons in relation to gravitational fields.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions how photons, which are mediators of electromagnetic forces, can escape the gravity of black holes, suggesting that black holes should not exert force if they cannot escape.
  • Another participant argues that the black hole's gravity does not need to escape to act on objects outside, referencing an external article for clarification.
  • A participant introduces the concept of virtual photons transmitting the Coulomb force, noting that they do not need to travel at the speed of light, but expresses uncertainty about the rigor of this explanation.
  • Further discussion highlights that while virtual photons are a quantum concept, a classical explanation should also be possible, as mentioned in the referenced article.
  • Some participants clarify that the original question may have been framed in quantum terms, but argue that a classical description could suffice for larger black holes.

Areas of Agreement / Disagreement

Participants express differing views on whether the original question pertains to quantum mechanics or can be addressed classically. There is no consensus on the necessity of a quantum explanation versus a classical one.

Contextual Notes

Some participants note the limitations of using virtual photons in classical explanations and the potential misunderstandings surrounding the terms used in the discussion.

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this seems like a dumb question but i just can't think of a solution. black holes can suck photons, that's why they are black. but there are charged black holes, and the EM forces is mediated by photons, so how can the mediating photon escape the gravity? also arent the gravitons (i know gravitons is unconfirmed...) themselves subject to the same thing? so in other words black holes should just be a dot in space with no force around it.
 
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An explanation I've seen is that the Coulomb force is transmitted by virtual photons, which don't have to travel at c. I'm not strong enough at field theory to know whether this is really a rigorous explanation.
 
bcrowell said:
An explanation I've seen is that the Coulomb force is transmitted by virtual photons, which don't have to travel at c.

The Usenet article mentions this, but it links to other articles which discuss the limitations of this view. Also, as the article notes, virtual photons are a quantum concept, and it should be possible to have a classical explanation of what's going on (which the article provides).
 
PeterDonis said:
Also, as the article notes, virtual photons are a quantum concept, and it should be possible to have a classical explanation of what's going on (which the article provides).

The OP's question was explicitly quantum-mechanical.

I don't see why there would be any mystery classically.
 
bcrowell said:
The OP's question was explicitly quantum-mechanical.

In the sense that the term "photon" was used, yes, it is on its face. But that term gets used a lot to mean something that is much more accurately described as either a classical EM field or a classical "pulse of EM radiation". Also, physically speaking, unless the black hole is of very small mass, a classical description should be sufficient.

bcrowell said:
I don't see why there would be any mystery classically.

I don't think there is either, but I'm not sure the OP realized that there isn't.
 

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