Black holes and spin

[Moontanman]

As a star collapses into a black hole would it's spin rate increase as it gets smaller?

 

If so is it possible that this spin is what keeps a black hole from collapsing into a one dimensional Point?

 

Over eons wouldn't the spin of a black hole slow down due to friction of it's magnetic field?

 

If so could there be a point in time when the black holes spin can no longer keep it from collapsing further and the black hole would completely vanish from our universe, even gravitationally?

 

My thinking is that at various stages different forces keep a star from collapsing further but as each of these forces is overwhelmed by gravity the mass becomes ever more concentrated, would spin be the last force keeping the black hole from collapsing completely out of our universe?

 

 

I hope this made some sense, it seemed to be more reasonable until i typed it out...

[Airbrush]

Certainly all black holes must spin, because stars spin, and even if the star is slowly spinning, when it collapses into a black hole any spin will be immensely increased, like the spinning ice skater bringing their arms in. They relatively quickly lose energy and lose spin, but will always be spinning some. But black holes are there and if they vanished gravitationally then they wouldn't exist, and yet they are still there. If your theory was correct, there would be fewer black holes.

 

"Rotating black holes are formed in the gravitational collapse of a massive spinning star or from the collapse of a collection of stars or gas with a total non-zero angular momentum. As most stars rotate it is expected that most black holes in nature are rotating black holes. In late 2006, astronomers reported estimates of the spin rates of black holes in the Astrophysical Journal. A black hole in the Milky Way, GRS 1915+105, may rotate 1,150 times per second, approaching the theoretical upper limit.

 

"A rotating black hole can produce large amounts of energy at the expense of its rotational energy. This happens through the Penrose process in the black hole's ergosphere, an area just outside its event horizon. In that case a rotating black hole gradually reduces to a Schwarzschild black hole, the minimum configuration from which no further energy can be extracted, although the Kerr black hole's rotation velocity will never quite reach zero."

 

http://en.wikipedia.org/wiki/Rotating_black_hole

Edited November 28, 2012 by Airbrush

[justinater22]

I believe Stephen hawking had a theory in which the black hole would get smaller and slower until it fell into itself causing some kind of explosion that would be easy to see. So to prove that you would just have to see the radiation of the explosion.

[Airbrush]

I believe Stephen hawking had a theory in which the black hole would get smaller and slower until it fell into itself causing some kind of explosion that would be easy to see. So to prove that you would just have to see the radiation of the explosion.

The theory is that black holes evaporate by Hawking Radiation. Just before it disappears it explodes. This can only be seen by us to happen to very tiny, primordial black holes, because stellar black holes will take Googols of years to evaporate to that degree, and the universe has only been around for less than 14 Billion years.