Is a toroidal black hole possible?

[Meatbot]

What would happen if you created a solar system-sized massive torus and kept adding mass evenly until it became a black hole. Let's say it's also spinning fast enough to keep itself from collapsing. Would you get a toroidal black hole? What would happen if you were inside the toroidal event horizon? What would happen if you were at the center of the torus?

 

[xantox]

If the torus is spinning too fast (above the Kerr limit) then no black hole would form, but instabilities will deviate it from axisymmetry and ultimately break it in pieces. Conversely, if a black hole forms, then it will always settle to a spherical shape. Toroidal horizons may only exist temporarily (eg as a consequence of a black hole merger).

 

[DaveC426913]

What would happen if you created a solar system-sized massive torus and kept adding mass evenly until it became a black hole. Let's say it's also spinning fast enough to keep itself from collapsing. Would you get a toroidal black hole? What would happen if you were inside the toroidal event horizon? What would happen if you were at the center of the torus?

A toroidal black hole is actually one of the pieces in a theoretically possible time machine. (I really should get a source for this, as I've raised it before and ben unable to defend it.) I think it probably involves frame-dragging.

 

[Meatbot]

How about a hypertoroidal of hyperspherical black hole?

 

[xantox]

How about a hypertoroidal of hyperspherical black hole?

I believe static black holes in N dimensions (eg, if string theory is true, etc) must be hyperspherical as in the Schwarzschild-Tangherlini solution, however if the black hole is charged or rotates the shape is not unique.