A hypothetical celestial object which expands outwards from a space–time singularity and emits energy, in the manner of a time-reversed black hole.
- ‘Even though both black holes and white holes are plausible scenarios according to general relativity, there is still a crucial difference.’
- ‘It is still true that a black hole may in some way explode as a white hole, but we have no idea if it can, if it will, and if so, at what point this would happen.’
- ‘And just as Humphreys' model has the universe expanding out of a white hole (a black hole running in reverse) so too does their paper!’
- ‘A white hole emits lots of light photons.’
- ‘The problem is with the amount of entropy in a white hole.’