Black Holes as 2 Dimensional Objects

[twofish-quant]

I chose that as a safe example. It's clear that there is probably a more complete description of the black hole in terms of horizon degrees of freedom, going far beyond the original membrane paradigm.

The reason I said that this was a calculation trick is that there is genre of "crankish papers" that argue that black holes don't exist because time freezes at the event horizon. I didn't want an informed newbie to be led astray.

I'm a big fan of the membrane paradigm because it allows non-GR specialists to think about situations when GR is involved.

 

[Vastin]

And it's pretty clear that the true theory of gravity is something similar to GR. One problem with assuming something weird happens at the event horizon is that the strength of the gravity isn't that high so something weird that happens at the event horizon would presumably cause something weird to happen in other situations.

The other problem is that "how does gravity know that it's in an event horizon." So we have a theory of gravity that behaves exactly like GR outside of the event horizon, but then goes nuts the moment you move inside. But gravity has no way of knowing that it's inside the event horizon or outside, and having gravity behave differently based on where you are, causes lots of problems.

Oh yes. It's cool weird stuff, but it don't have a black hole nearby that I can test things with. Conversely I can check GR because my GPS works.

Yeah, I'm really not trying to contest GR - my GPS works too. ;)

But I am trying to determine if there are domains where it is not as accurate as we would like, or possibly separate/related phenomena that prevents matter in a high density (near plank length) configuration from behaving as we expect as it attempts to pass through such a gravity field.

Basically, it's not so much the behavior of gravity I'm concerned with here - it's the behavior of matter. If, as you say, the gravity at the event horizon is non-infinite, then in theory it could be counterbalanced by another force at that point, preventing that matter from falling further. If two very powerful forces of this sort are arrayed directly against each other, you might get the sort of plank shell configuration that would help us prevent data loss - the question is, do we have any candidates for the outward pressure?

Does matter, for example, have a state of final compression beyond which it cannot be pushed, regardless of the energy applied? It it possible that rather than resisting the essentially 'infinite' pressure it would face at the singularity point, that it manages to find an incompressible equilibrium resting at the edge of the event horizon in stable orbit with its light cone resting precisely on the horizon? I presume that light cones generally narrow as the gravitational field increases, and I'm guessing that under the correct conditions that cone might be reduced to a line.

 

[Vastin]

At that point you have to ask "what is information?" ***From the point of view of an outside observer*** things appear to freeze when you cross the event horizon, and you can use that to store information. The fact that in fact this is something of an optical illusion doesn't change the fact that information is stored.

I thought that the image trapped at the edge of an event horizon was red-shifted virtually out of existence and effectively invisible to any form of external detection?

Not sure what that means for the data it represents to be honest. The idea of the information being stripped 'off' of matter as it falls through the event horizon, so that 'information-less' mass is accreting into the singularity while its data is stored on the EH until such time as the mass is allowed to evaporate off, at which point it 'retrieves' its data from the EH on the way out.

That's a pretty exotic arrangement, and it doesn't even remotely protect us from the idea that something fantastic needs to happen at the EH boundary - it makes that event much weirder, as we have matter being stripped of almost all its properties except mass, with mass-less data being stored in the fabric of space-time and data-less mass falling into a singularity.

Ick.