Escaping Black Holes: Questions & Answers

[typical guy]

Several questions about escaping the event horizon of a black hole

typical disclaimer: I am not a scientist so please don't scold me too much for curiosity.

I imagine a large black hole with a less massive black hole in orbit around it. Light enters the event horizon of the more massive black hole (or the smaller one when it's about to orbit closest to the larger bh). The smaller bh distorts the event horizon creating a lagrange location somewhere that used to be within the event horizon. The light now flys away from or passes around the massive bh. Is this a way to escape the event horizon?


edit:
Question 2, since the universal expansion is accelerating, in the distant future could light enter the event horizon of a black hole and have the space it is located expand so rapidly that it is no longer inside the hoizon?


Question 3, Can light enter the event horizon immediatly before the black hole evaporates away? Would it then 'escape'?

 

[Jonathan Scott]

typical disclaimer: I am not a scientist so please don't scold me too much for curiosity.

I imagine a large black hole with a less massive black hole in orbit around it. Light enters the event horizon of the more massive black hole (or the smaller one when it's about to orbit closest to the larger bh). The smaller bh distorts the event horizon creating a lagrange location somewhere that used to be within the event horizon. The light now flys away from or passes around the massive bh. Is this a way to escape the event horizon?


edit:
Question 2, since the universal expansion is accelerating, in the distant future could light enter the event horizon of a black hole and have the space it is located expand so rapidly that it is no longer inside the hoizon?


Question 3, Can light enter the event horizon immediatly before the black hole evaporates away? Would it then 'escape'?

There is no escape from a black hole by any means known to science.

When one black hole approaches another, the potentials combine to cause the event horizons to expand towards one another, making it more difficult for something in between to escape, not easier. Basically, that something now has to escape from two black holes instead of one, and although the local field is less, it is "deeper" down in the potential than it would have been from either one alone.

 

[ibysaiyan]

There is no escape from a black hole by any means known to science.

When one black hole approaches another, the potentials combine to cause the event horizons to expand towards one another, making it more difficult for something in between to escape, not easier. Basically, that something now has to escape from two black holes instead of one, and although the local field is less, it is "deeper" down in the potential than it would have been from either one alone.

I thought that say if you get a collision of black holes you'd see them act same as two spinning tops hitting each other maybe the article wasn't clear and spoke of the whole BH (including accreting disc) instead of just the EH.

 

[Jonathan Scott]

I thought that say if you get a collision of black holes you'd see them act same as two spinning tops hitting each other maybe the article wasn't clear and spoke of the whole BH (including accreting disc) instead of just the EH.

The original post mentions the event horizon in each case. There is no escape from beyond the event horizon.

 

[typical guy]

There is no escape from a black hole by any means known to science.

When one black hole approaches another, the potentials combine to cause the event horizons to expand towards one another, making it more difficult for something in between to escape, not easier. Basically, that something now has to escape from two black holes instead of one, and although the local field is less, it is "deeper" down in the potential than it would have been from either one alone.

so are you saying gravity works differently in theoretical descrptions of black holes than it does with respect to the earth/moon/sun system? I'm pretty sure lagrange points are well known?

You did not address my other questions.

 

[IsometricPion]

There was a similar https://www.physicsforums.com/showthread.php?t=478951" about the same topic about a month ago. Perhaps some of those posts will be helpful.

 

[Nabeshin]

so are you saying gravity works differently in theoretical descrptions of black holes than it does with respect to the earth/moon/sun system? I'm pretty sure lagrange points are well known?

Yes. Specifically, one uses Newtonian gravity to derive lagrange points, not GR. Jonathan Scott's post is dead on (You can read my remarks in the thread IsometricPion linked to for more detail).

Question 2: The universal expansion is only a valid model when the universe is homogeneous and isotropic! A black hole certainly does not represent such a scenario, and thus the expansion is not applicable there.

Question 3: If the light enters the event horizon EVER, it will never propagate out to the rest of the universe. Far from being a deep fact, this is the very DEFINITION of the event horizon!