A singularity in space which, opposite the situation in a black hole, emits large amounts of matter and energy. Theoretically possible in the pure mathematics of black holes, but extremely unlikely to have any relationship to actual physical reality.
Hypothetical opposite of the black hole. Out of it matter and radiation emerge from another Universe into our own Universe.
a black hole running backwards in time
a place where (if it could exist with any matter in it - which it can't) matter would pop out into the universe
a time-reversed black hole
The time reversal of a black hole. Big bang is an example of a white hole. A theoretical region of space-time where matter erupts but cannot enter the region.
The time-reversal of a black hole. A white hole is a singularity from which matter emerges unpredictably, but into which matter cannot enter. The initial singularity of the standard big bang theory is an example of a white hole. It can be shown that the creation of a new universe from a false vacuum bubble in the context of classical General Relativity would require a white hole singularity, which means essentially that it cannot be done, even in principle. However, a false vacuum bubble could conceivably grow to become a new universe through a process of quantum tunneling. [G97
A white hole is the time reversal of a black hole, another singularity in space-time. Matter emerges unpredictably from a white hole (unlike a black hole, into which matter is drawn). An example of a white hole is the original singularity of the Big Bang.
In astrophysics, a white hole is a postulated celestial body that is the time reversal of a black hole. While a black hole acts as a point mass that attracts and absorbs any nearby matter, a white hole acts as a point mass that repels or (perhaps) even ejects matter.
White Hole was the fourth epsiode to air in the fourth series of Red Dwarf.
