What Would Happen if Two Black Holes Got Too Close?

In summary: Yes, time dilation and redshift can result in an event horizon merger appearing to an external observer as if it had taken place over a period of years.
  • #1
Ultrastar 1
60
0
Hi everyone. Does anyone know what would happen if two black holes got too close toghether? Would the merge and become a supermassive black hole?
 
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  • #2
They would merge and form a black hole with mass roughly equal to the sum of the masses of the original black holes.
 
  • #3
nicksauce said:
They would merge and form a black hole with mass roughly equal to the sum of the masses of the original black holes.

You may have seen research papers based on computer simulations of such mergers:
BH+BH, or BH+Neutron Star,...

The two compact objects, while spiraling in close and then mutually swallowing each other, cause a fair amount of gravitational wave ripple. The idea of the research is to figure out what wave patterns to look for with gravitational wave detectors. Address questions like: Are the detectors being built going to be sensitive enough to "see" events like the merger of two compact objects?

It might be interesting to see some of the graphic output. I remember some from a few years back, but don't have any links handy.
 
  • #4
The merging of compact bodies i.e. neutron stars or black holes is a popular hypothesis as to the source of short, hard gamma ray bursts.
 
  • #5
marcus said:
You may have seen research papers based on computer simulations of such mergers:
BH+BH, or BH+Neutron Star,...

The two compact objects, while spiraling in close and then mutually swallowing each other, cause a fair amount of gravitational wave ripple. The idea of the research is to figure out what wave patterns to look for with gravitational wave detectors. Address questions like: Are the detectors being built going to be sensitive enough to "see" events like the merger of two compact objects?

It might be interesting to see some of the graphic output. I remember some from a few years back, but don't have any links handy.

This is, in fact, what I'm starting to do research in in Graduate school now.

There are a few pictures/movies here, for example, http://www.cita.utoronto.ca/~pfeiffer/
 
  • #6
nicksauce said:
This is, in fact, what I'm starting to do research in in Graduate school now.

There are a few pictures/movies here, for example, http://www.cita.utoronto.ca/~pfeiffer/

Hey, I work on this stuff!
 
  • #7
I've wondered, doesn't time "stop" (from an outside observer's point of view) at the event horizon of a BH? So how could anything fall into a BH or merge with one?
 
  • #8
Matterwave said:
I've wondered, doesn't time "stop" (from an outside observer's point of view) at the event horizon of a BH? So how could anything fall into a BH or merge with one?
Good point. Conventional theory suggests an outside observer sees an infalling observer 'freeze' at the event horizon. Black hole event horizons could, however, merge in time as measured by an outside observer.
 
  • #9
Chronos said:
Good point. Conventional theory suggests an outside observer sees an infalling observer 'freeze' at the event horizon. Black hole event horizons could, however, merge in time as measured by an outside observer.

Please forgive my ignorance here, but are you saying that an outside observer would note that an object crossing an event horizon would appear frozen there forever? And not, as Hollywood would have us believe, stretched into oblivion?
Of course, I'm not sure what an object would look like as it approached an event horizon, I'd assume it'd be disintegrated long before it actually crossed it.
 
  • #10
Objects approaching the event horizon of a black hole suffer from extreme time dilation and redshift from the perspective of a stationary external observer. Fortunately, a portion of all matter falling into a black hole is merely ripped to shreds and jetted back into space.
 
  • #11
Chronos said:
Objects approaching the event horizon of a black hole suffer from extreme time dilation and redshift from the perspective of a stationary external observer. Fortunately, a portion of all matter falling into a black hole is merely ripped to shreds and jetted back into space.

So, by "extreme" I guess you mean on the order of years?
I'm just trying to get a grasp on how this phenomena would appear to an outside observer.
I have a pretty good understanding of what happens to matter that has the misfortune to get sucked into a black hole, but I never thought about the relativistic effects that would be observed by a third party.
Thanks
 

Related to What Would Happen if Two Black Holes Got Too Close?

1. What are black holes?

Black holes are regions in space with such strong gravitational pull that nothing, including light, can escape from it. They are formed when a massive star dies and collapses in on itself.

2. What happens when two black holes get too close?

When two black holes get too close, they start to orbit around each other. As they continue to get closer, they eventually merge into one larger black hole.

3. Can black holes merge with other types of objects?

No, black holes can only merge with other black holes or objects that have already been consumed by a black hole.

4. What would be the impact of two black holes merging on the surrounding space?

The merging of two black holes would create intense gravitational waves, which would ripple through the surrounding space. This could cause disruptions in the orbits of nearby planets and stars.

5. Is it possible for two black holes to merge with each other without causing any impact?

No, the merging of two black holes always has an impact on the surrounding space due to the release of gravitational waves. However, the impact may not be significant depending on the distance of the black holes from other objects.

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