What happens when two black holes collide?

[varsha]

i want to know what exactly happens when two black holes collide. in detail.

 

[Soul Surfer]

Assuming no other material was present it is most likely that two black holes would swing a tight hyprbolic orbit around each other and go their way.

If they passed each other very closely it would be possible for there to be a significant radiation of gravitational energy for them to go into orbit around each other. For this to happen in non relatavistic circumstances this usually needs the gravitational influence of a third body or a physical collision. This orbit would gradually loose energy by gravitational radiation and the two holes would eventually fuse to make a single larger rotating black hole.

It is of course remotely possible if they were moving directly towards each other with no net angular momentum they would collide directly and instantly fuse to make a larger black hole.

Either way there is no particular reason for the radiation of anything other than gravitational energy (and of course the hawking radiation of the black holes themselves.

If there was other material present the signatures of the black holes accretion disks would be visible and mosulated by the orbits of the holes.

There is a link referred to elsewhere in this are which gives the gravitaitional wave signature of a pair of black holes in the final stages before they merge. This rising chirp of frequencies is expected to be one of the most detectable signals in the gravitiational wave environment and could be detected at vast distances.

 

[varsha]

what happens if two spinning black holes collide? will the effects be the same as u mentioned above? and can you tell me more about spinning black holes?

and oh, thanks for that info. i didn't know that last bit.

 

[Nereid]

Check out the work of http://www.phys.utb.edu/numrel/research_dir/lazarus.html".

 

[Stingray]

This is a very active research area, but only a few things are known even about collisions of nonrotating black holes (though this might be changing very soon). Adding spin goes beyond what anyone could tell you right now.