What happens when an object approaches an event horizon?

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Discussion Overview

The discussion revolves around the behavior of objects as they approach an event horizon, particularly focusing on the perspectives of different observers, such as Bob and Alice. It touches on concepts from general relativity, the Holographic Principle, and the implications of the Heisenberg Uncertainty Principle in this context.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant describes their understanding of an event horizon as being dependent on the observer's frame of reference, noting that Bob experiences a "No Drama" crossing while Alice perceives Bob's time slowing down and never reaching the event horizon.
  • Another participant questions the validity of the initial claims and seeks citations to support or refute the described effects, particularly regarding the implications of the Heisenberg Uncertainty Principle as Bob approaches the event horizon.
  • There is mention of a video by Susskind discussing the Holographic Principle, which some participants believe may provide insights relevant to the discussion, although there is uncertainty about its applicability to the claims made.
  • One participant expresses concern about mixing quantum mechanics with gravity, indicating that this is an area of ongoing struggle and uncertainty in the scientific community.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the interpretations of the event horizon and the associated effects. There are competing views on the implications of the Heisenberg Uncertainty Principle and the validity of the initial claims made about Bob and Alice's experiences.

Contextual Notes

Participants highlight the complexity of integrating quantum mechanics with gravitational theories, indicating that the discussion is limited by current understanding and unresolved theoretical frameworks.

.Scott
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My question is: Is my picture of what happens as something approaches an event horizon accurate - and are there any citations describing it?

I got my "picture" from a PBS broadcast several years ago. It was since mentioned in these forums, but I haven't been able to find an explicit mention of it in the literature accepted by this forum.

The picture is this: First, an event horizon is dependent on a frame of reference. One object "Bob" can enter the event horizon of the reference frame of another object "Alice". I've seen what Bob sees described as "No Drama" - he simply sees his watch cross through some particular time, say noon, as he crosses the horizon.

On the other hand, red shift and other effects prevent Alice from "seeing" much at all. But the events as described from her reference frame would be:
1) Bob's watch never reaches noon and Bob never reaches the event horizon. In Alice's universe, Bob's time slows almost to a stop.
2) Because of this "time freeze" and HUP, Bob's location cannot remain definite - and he begins to spread out over the event horizon.

It's that last point that I'm having trouble with. When I try to find citable papers on how the issues resolved the bet (at least in the minds of Preskill and Hawkings), I find "Euclidean path integrals" with no mention of this "popular" explanation.

Still, it makes sense that Bob cannot remain both stationary in time and fixed in space from Alice's reference frame. So I expect that Bob would take on an indefinite position - again, in Alice's reference frame.

So what is the real scoop?
 
Physics news on Phys.org
Stanford U's Susskind on the development of the Holographic Principle 55 minutes.
 
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So, don't miss Susskinds jeremiad on erroneous take-aways from difficult analogies.
 
From my work computer, I cannot view that video - but "thanks", I'm pretty sure what the content would be and I'll view it later.

Is that a citable source according to these forum rules? I have two reasons for asking. First is that I replied to a post describing this effect and was told it was misinformation. Second, it seems to bear on the "firestorm" that is currently being described as occurring behind the event horizon - and I don't want to walk into that question without being sure on this point.
 
Doug Huffman said:
So, don't miss Susskinds jeremiad on erroneous take-aways from difficult analogies.
I won't. Especially since I am tempted to make some potentially erroneous take-aways.
 
Doug Huffman said:
Stanford U's Susskind on the development of the Holographic Principle 55 minutes.
That video made quick mention of Heisenberg Uncertainty Principle, but not at all in the way I had seen it presented before. In the earlier video, Alice had a chance to spread out. In this case, she simply fried. I think what happens is both.

What was really interesting about the video was Suskind's terse description of how Alice's view of Alice compares to Bob's view of Alice. It is simply that both are views of the same event from different reference frames.

This leads directly into my question about the black hole firewall - which I will post in another thread.
 
You are mixing quantum mechanics and gravity, which is something we don't know how to do.
 
Khashishi said:
You are mixing quantum mechanics and gravity, which is something we don't know how to do.
We'll have to struggle with it.
 

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