Two identical black holes, but rotating in opposite directions collide

[Greglar]

What would happen? Would the result be a non-rotating black hole? During their collision when their ergospheres overlap, would it generate an area where nothing could move in either direction along the plane of rotation? Also, since the force of their gravitational pull would be the same, would they cancel each other out? Like would particles in the overlapping event horizons no longer fall towards either black hole?

 

[atyy]

Some places to start looking:
http://arxiv.org/abs/gr-qc/0701164
http://arxiv.org/abs/gr-qc/0702133
http://arxiv.org/abs/gr-qc/0702052
http://arxiv.org/abs/0708.3999
http://arxiv.org/abs/1011.3281

The second of those seems most relevant: "Here we report the first systematic study of gravitational recoil of equal-mass binaries with equal, but anti-aligned, spins parallel to the orbital plane. Such an orientation of the spins is expected to maximize the recoil. We find that recoil velocity (which is perpendicular to the orbital plane) varies sinusoidally with the angle that the initial spin directions make with the initial linear momenta of each hole and scales up to a maximum of ~4000 km/s for maximally-rotating holes."

 

[Greglar]

Awesome thanks! A lot more stuff goes on then I was expecting haha