<p>The only places around one black hole where gravity would be strong enough to pull an object out from inside the horizon of another black hole are all inside the horizon of the first hole.</p>

<p>Remember that <em>at minimum</em> an object just inside the horizon of a black hole is traveling toward the center at the speed of light (as its speed would be measured from outside the hole, if we could see it) and getting faster. For a second black hole to catch up to the object to pull it out, it would itself have to be moving faster than the object - faster than light - which is obviously impossible but anyway would simply merge the two black holes, without rescuing anything. </p>

CC BY-SA 3.0
2017-10-19T09:18:57.947Z
Although I am very familiarized with the relativity theory, the limits of the speed of light and these features, I never realized that an object inside the event horizon would look at the speed of light observed from outside.
This clarifies my question. 
Thank you.
Daniel Ortega
CC BY-SA 3.0
2017-10-15T03:29:39.540Z
2017-10-15T03:29:39.540Z
Asher
<p>I watched this simulation made by LIGO (Laser Interferometer Gravitational-Wave Observatory) where 2 black holes merge into one.</p>

<p><a href="https://www.youtube.com/watch?v=I_88S8DWbcU" rel="noreferrer">https://www.youtube.com/watch?v=I_88S8DWbcU</a></p>

<p>I was therefore thinking that theoretically nothing can escape a black hole given the features of the space and the black hole remain the same due to the strong gravity.</p>

<p>However, I was thinking if 2 black holes stay together close enough, the "event horizon" would reshape as well.</p>

<p>We all know the gravity force is F=G(Mm/r^2).</p>

<p>Given a point next to the event horizon but "inside" the black hole the gravity there will be so strong that the Escape velocity will be higher than C (speed of light).</p>

<p>If we place another massive object (like another blackhole in the proximities of this point, but far enough, the gravity there will be counteracted and therefore this point will be able to escape its black hole, reshaping the event horizon and making it smaller. (We will have created a "concavity" in the event horizon)</p>

<p>My question is:</p>

<p>Given a hypothetical scenario where we create thousands of micro blacholes orbiting the main blackhole, in a gravitational equlibrium. Would we be able to reshape and "push" the event horizon strong enough that objects inside could now use the chance and escape?</p>

<p>Could we even pull the matter of the black hole and make it less dense along the time even transforming it into a start destroying the singularity?</p>

CC BY-SA 3.0
2017-10-09T12:08:22.133Z
You're applying Newtonian ideas of gravity to a concept that *requires* general relativity to make sense of.  Escape velocity is not a useful concept in black hole (event horizon) theory.  The distortion of space-time is the key to understanding them.
StephenG - Help Ukraine
CC BY-SA 3.0
2017-10-10T17:29:05.500Z
Related: https://physics.stackexchange.com/q/1134/56299, https://physics.stackexchange.com/q/39253/56299.
HDE 226868
<black-hole><event-horizon>
Reshaping black holes to "push" the event horizon
Daniel Ortega
# Reshaping black holes to "push" the event horizon

(Asked by: username_0 on 2017-10-09)

I watched this simulation made by LIGO (Laser Interferometer Gravitational-Wave Observatory) where 2 black holes merge into one.

<https://www.youtube.com/watch?v=I_88S8DWbcU>

I was therefore thinking that theoretically nothing can escape a black hole given the features of the space and the black hole remain the same due to the strong gravity.

However, I was thinking if 2 black holes stay together close enough, the "event horizon" would reshape as well.

We all know the gravity force is F=G(Mm/r^2).

Given a point next to the event horizon but "inside" the black hole the gravity there will be so strong that the Escape velocity will be higher than C (speed of light).

If we place another massive object (like another blackhole in the proximities of this point, but far enough, the gravity there will be counteracted and therefore this point will be able to escape its black hole, reshaping the event horizon and making it smaller. (We will have created a "concavity" in the event horizon)

My question is:

Given a hypothetical scenario where we create thousands of micro blacholes orbiting the main blackhole, in a gravitational equlibrium. Would we be able to reshape and "push" the event horizon strong enough that objects inside could now use the chance and escape?

Could we even pull the matter of the black hole and make it less dense along the time even transforming it into a start destroying the singularity?

**Tags:** black-hole, event-horizon

> **Comments:**
> **username_1**: You're applying Newtonian ideas of gravity to a concept that *requires* general relativity to make sense of.  Escape velocity is not a useful concept in black hole (event horizon) theory.  The distortion of space-time is the key to understanding them.  
> **username_2**: Related: https://physics.stackexchange.com/q/1134/56299, https://physics.stackexchange.com/q/39253/56299.  

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## 1 answers

### Answer by username_3 on 2017-10-15. Score: 5 | Accepted answer

The only places around one black hole where gravity would be strong enough to pull an object out from inside the horizon of another black hole are all inside the horizon of the first hole.

Remember that *at minimum* an object just inside the horizon of a black hole is traveling toward the center at the speed of light (as its speed would be measured from outside the hole, if we could see it) and getting faster. For a second black hole to catch up to the object to pull it out, it would itself have to be moving faster than the object - faster than light - which is obviously impossible but anyway would simply merge the two black holes, without rescuing anything.

> **Comments:**
> **username_0**: Although I am very familiarized with the relativity theory, the limits of the speed of light and these features, I never realized that an object inside the event horizon would look at the speed of light observed from outside. This clarifies my question.  Thank you.  

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