Types of Black Holes
There are four known, exact, black hole solutions to Einstein's equations, which describe gravity in General Relativity. Two of these (the Kerr and Kerr-Newman black holes) rotate. It is generally believed that every black hole decays rapidly to a stable black hole; and, by the no-hair theorem, that (modulo quantum fluctuations) stable black holes can be completely described at any moment in time by these eleven numbers:
- mass-energy M,
- linear momentum P (three components),
- angular momentum J (three components),
- position X (three components),
- electric charge Q.
These numbers represent the conserved attributes of an object which can be determined from a distance by examining its electromagnetic and gravitational fields. All other variations in the black hole will either escape to infinity or be swallowed up by the black hole. This is because anything happening inside the black hole horizon cannot affect events outside it.
In terms of these properties, the four types of stable black holes can be defined as follows:
| Nonrotating (J = 0) | Rotating (J > 0) | |
| Uncharged (Q = 0) | Schwarzschild | Kerr |
| Charged (Q ≠ 0) | Reissner-Nordström | Kerr-Newman |
Read more about this topic: Rotating Black Hole
Famous quotes containing the words types of, types, black and/or holes:
“... there are two types of happiness and I have chosen that of the murderers. For I am happy. There was a time when I thought I had reached the limit of distress. Beyond that limit, there is a sterile and magnificent happiness.”
—Albert Camus (1913–1960)
“He types his laboured column—weary drudge!
Senile fudge and solemn:
Spare, editor, to condemn
These dry leaves of his autumn.”
—Robertson Davies (b. 1913)
“As I was going by Charing Cross,
I saw a black man upon a black horse;
They told me it was King Charles the First—”
—Unknown. As I was going by Charing Cross (l. 1–3)
“Why are all these dolls falling out of the sky?
Was there a father?
Or have the planets cut holes in their nets
and let our childhood out,
or are we the dolls themselves,
born but never fed?”
—Anne Sexton (1928–1974)