has definition 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. | ![has source: Guth, A.H. 1997 The Inflationary Universe, Addison-Wesley, 2001-09-27 09:30:09.0 has source: Guth, A.H. 1997 The Inflationary Universe, Addison-Wesley, 2001-09-27 09:30:09.0](facet.gif) |