What events occur inside a black hole?

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Discussion Overview

The discussion revolves around the events that occur inside a black hole, particularly focusing on the perspectives of two observers, one inside and one outside the event horizon. It explores concepts related to relativity, the nature of black holes, and the implications of gravitational effects on observers.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that an observer outside a black hole (B) will see an observer falling in (A) slow down as they approach the event horizon, while A will continue to see B until passing the horizon.
  • Others argue that A will appear to hover at the event horizon and never be observed falling in, while A experiences stretching due to tidal forces.
  • There is a claim that no events occur inside a black hole because it is suggested that black holes do not have an interior.
  • Some participants discuss the difficulties in rigorously defining the concept of "inside the event horizon" and the implications of the event horizon as an asymptotic limit.
  • Others challenge the assertion that the region inside the event horizon can be rigorously defined, citing the lack of a timelike Killing vector in that region.
  • There are claims that the Schwarzschild metric provides a well-defined approach to understanding black holes, despite the complexities involved.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of events inside a black hole and the definitions surrounding the event horizon. The discussion remains unresolved with differing interpretations and understandings of the underlying physics.

Contextual Notes

Limitations include the ambiguity in defining the interior of a black hole and the event horizon, as well as the dependence on various coordinate systems that may not be well-behaved in certain contexts.

F1225
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As we know, the gravitational pull of the black hole is too strong, not even light can escape from it...


Let me assume 2 person: A and B
A is sucked into a black hole while B is outside the event horizon...
At first, B will notice that A has disappeared due to the lights(image) of A is sucked by the black hole...
On the other hand, A will still see the image of B because the lights(image) of B is being sucked into the black hole.

What this all mean? Do this event relates to relativity which both of them are in different inertial frame causing things which they observed to differs?


Thanks for spending your time reading the entire post...*(it's quite long)...haha :-p
 
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F1225 said:
As we know, the gravitational pull of the black hole is too strong, not even light can escape from it...Let me assume 2 person: A and B
A is sucked into a black hole while B is outside the event horizon...
At first, B will notice that A has disappeared due to the lights(image) of A is sucked by the black hole...
On the other hand, A will still see the image of B because the lights(image) of B is being sucked into the black hole.

What this all mean? Do this event relates to relativity which both of them are in different inertial frame causing things which they observed to differs?

Person B will NOT see A sucked into the black hole, he will see A move more and more slowly as A approaches the event horizon of the BH. That isn't what actually happen to A of course, but it is what B will see. A will just continue on through the EH as though it were not there.

You are correct that A will continue to see B, even after A passes the event horizon
 
jedishrfu said:
my understanding is that A will appear to hover on the event horizon and will never be observed falling in. From A's perspective though, A will pass the event horizon and continue the fall being stretched out like taffy due to gravitational tidal effects.

Well, that's not what you said in your original post, thus my answer.

The sphagettification may occur either inside or outside the BH, depending on its size.
 
phinds said:
Well, that's not what you said in your original post, thus my answer.

The sphagettification may occur either inside or outside the BH, depending on its size.

I'm confused who are you talking about, I only posted once. ?
 
jedishrfu said:
I'm confused who are you talking about, I only posted once. ?

DOH ! Sorry about that. I clearly wasn't paying attention and though you were the OP again.
 
phinds said:
DOH ! Sorry about that. I clearly wasn't paying attention and though you were the OP again.

NP, I thought one of us had fallen into that black hole and I wasnt sure which one.
 
No events occur inside a black hole because black holes don't have an interior.
 
ahhaha said:
No events occur inside a black hole because black holes don't have an interior.

You are right (according to most theories) but the term "inside a black hole" normally just means "inside the event horizon".
 
  • #10
"inside the event horizon" can't be made rigorous, if only because the notion of event horizon( assuming it can be made rigorous) is no more rigorous than the notion of BH interior since an event horizon is an asymptotic limit of future null infinity. In the usual OpSnyVolk representation of Schwarz that's where the radial coordinate magically turns into the temporal coordinate. At that point you don't know where you are! Next to nonsense, or in it?
 
  • #11
ahhaha said:
"inside the event horizon" can't be made rigorous, if only because the notion of event horizon( assuming it can be made rigorous) is no more rigorous than the notion of BH interior since an event horizon is an asymptotic limit of future null infinity. In the usual OpSnyVolk representation of Schwarz that's where the radial coordinate magically turns into the temporal coordinate. At that point you don't know where you are! Next to nonsense, or in it?
This is incorrect. Inside the event horizon can easily be made rigorous. E.g. The region without a timelike killing vector.

Also, there are several coordinate charts that are well behaved at the EH, so the failure of one is clearly a problem with those coordinates, not the EH itself.
 
  • #12
Your "region" can't be well defined since its domain is rest of universe. A singularity or BH can only make sense when it's approached from asymptotic spatial infinity and an effective approach may not be complete in the assumed metric. So I would ask you where in the approach is the path without timelike vector?
 
  • #13
ahhaha said:
Your "region" can't be well defined since its domain is rest of universe. A singularity or BH can only make sense when it's approached from asymptotic spatial infinity and an effective approach may not be complete in the assumed metric.

Yes, an effective approach may not be possible in some metrics, but the Schwarzschild metric solution to the Einstein field equations isn't one of these. You just have to transform from the Schwarzschild coordinates to some other coordinates that are better-behaved at the event horizon.

So I would ask you where in the approach is the path without timelike vector?
Dalespam didn't say "without a timelike vector", he said "without a timelike Killing vector". There's no shortage of timelike vectors at and inside the event horizon. The lack of a timelike Killing vector just means that there exists no coordinate system in which the metric components can be independent of time - not too surprising because all timelike geodesics converge on the central singularity.
 
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  • #14
ahhaha said:
Your "region" can't be well defined since its domain is rest of universe. A singularity or BH can only make sense when it's approached from asymptotic spatial infinity
This is a complete non-sequitor. What do the size of a domain or required approaches have to do with being well-defined? Well defined means only that it has a definition which is unambiguous, not any of the unrelated concepts you are trying to bring in. The term "inside the EH" is well defined.


ahhaha said:
and an effective approach may not be complete in the assumed metric. So I would ask you where in the approach is the path without timelike vector?
I don't know what you are trying to say here.
 

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