In theoretical physics, a near-extremal black hole is a black hole which is not far from the minimal possible mass that can be compatible with the given charges and angular momentum. The calculations of the properties of near-extremal black holes are usually performed using perturbation theory around the extremal black hole; the expansion parameter is called non-extremality.
In supersymmetric theories, near-extremal black holes are often small perturbations of supersymmetric black holes. Such black holes have a very small Hawking temperature and consequently emit a small amount of Hawking radiation. Their black hole entropy can often be calculated in string theory, much like in the case of extremal black holes, at least to the first order in non-extremality.
Famous quotes containing the words black and/or hole:
“Black women ... work because their husbands can’t make enough money at their jobs to keep everything going.... They don’t go to work to find fulfillment, or adventure, or glamour and romance, like so many white women think they are doing. Black women work out of necessity.”
—Wilma Rudolph (1940–1994)
“It was a blonde. A blonde to make a bishop kick a hole in a stained-glass window.”
—Raymond Chandler (1888–1959)