Escaping Black Holes: Questions & Answers

In summary, the event horizon of a black hole cannot be escaped by any known means. The merging of two black holes can make it even more difficult for something to escape by expanding the event horizon. The concept of lagrange points and universal expansion do not apply to black holes. Once light enters the event horizon, it can never escape.
  • #1
typical guy
24
0
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'?
 
Last edited:
Astronomy news on Phys.org
  • #2


typical guy said:
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.
 
  • #3


Jonathan Scott said:
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.
 
  • #4


ibysaiyan said:
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.
 
  • #5
Jonathan Scott said:
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.
 
  • #7


typical guy said:
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!
 

1. What is a black hole?

A black hole is a region in space where the gravitational pull is so strong that nothing, including light, can escape from it. It is formed when a massive star dies and its core collapses in on itself.

2. How do you escape a black hole?

Currently, it is not possible to escape a black hole once you have crossed its event horizon. The extreme gravitational pull and the distortion of space-time make it impossible for anything to escape.

3. Can anything survive a black hole?

It is highly unlikely that anything can survive a black hole. The intense gravity of a black hole would crush any object, including humans, into a singularity. Even if an object could survive the crushing force, it would be stretched and torn apart by the extreme tidal forces.

4. Is it possible to travel through a black hole?

Currently, there is no known way to travel through a black hole. The intense gravitational pull and the distortion of space-time would make it impossible for any spacecraft to survive the journey.

5. Can black holes merge?

Yes, black holes can merge when two or more of them come close enough to each other. This usually happens when two galaxies collide, bringing their respective black holes together. This process is known as a black hole merger and can create a larger, more massive black hole.

Similar threads

Replies
4
Views
464
  • Astronomy and Astrophysics
Replies
5
Views
1K
  • Astronomy and Astrophysics
Replies
4
Views
2K
  • Astronomy and Astrophysics
Replies
12
Views
1K
Replies
5
Views
1K
  • Astronomy and Astrophysics
Replies
11
Views
3K
  • Astronomy and Astrophysics
Replies
2
Views
1K
  • Astronomy and Astrophysics
Replies
6
Views
1K
  • Special and General Relativity
2
Replies
35
Views
771
  • Special and General Relativity
2
Replies
62
Views
3K
Back
Top