What Would Happen if Two Black Holes Got Too Close?

[Ultrastar 1]

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?

 

[nicksauce]

They would merge and form a black hole with mass roughly equal to the sum of the masses of the original black holes.

 

[marcus]

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.

 

[Phyisab****]

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.

 

[nicksauce]

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/

 

[Nabeshin]

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!

 

[Matterwave]

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?

 

[Chronos]

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.

 

[BigSteve]

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.

 

[Chronos]

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.

 

[BigSteve]

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