Cosmic censorship hypothesis

The New Bet

Whereas Stephen W. Hawking (having lost a previous bet on this subject by not demanding genericity) still firmly believes that naked singularities are an anathema and should be prohibited by the laws of classical physics,

And whereas John Preskill and Kip Thorne (having won the previous bet) still regard naked singularities as quantum gravitational objects that might exist, unclothed by horizons, for all the Universe to see,

Therefore Hawking offers, and Preskill/Thorne accept, a wager that

When any form of classical matter or field that is incapable of becoming singular in flat spacetime is coupled to general relativity via the classical Einstein equations, then

A dynamical evolution from generic initial conditions (i.e., from an open
set of initial data) can never produce a naked singularity
(a past-incomplete null geodesic from scri-plus).

The loser will reward the winner with clothing to cover the winner's nakedness. The clothing is to be embroidered with a suitable, truly concessionary message.

Stephen W. Hawking, John P. Preskill, Kip S. Thorne
Pasadena, California, 5 February 1997

In general relativity, the cosmic censorship hypothesis (CCH) is a conjecture about the nature of singularities in spacetime.

Singularities that arise in the solutions of Einstein's equations are typically hidden within event horizons, and therefore cannot be seen from the rest of spacetime. Singularities which are not so hidden are called naked. The weak cosmic censorship hypothesis conjectures that no naked singularities other than the Big Bang singularity exist in the universe. The hypothesis was conceived by Roger Penrose in 1969.