The concept of black hole entropy is generalized to cosmological event horizons. An analogue of the Bekenstein-Hawking generalized second law of thermodynamics is suggested. This law is illustrated by considering entropy changes in various black hole de Sitter spacetimes, and also with the help of a viscous-driven de Sitter universe model, which provides a cosmological version of a far-fromequilibrium dissipative structure. The law apparently fails for some recontractinguniverse models. This indicates that a contribution to the gravitational entropy has been omitted. A possible remedy involving algorithmic complexity theory is suggested. I propose the use of a cosmic "entropy censorship" hypothesis as a filter for acceptable field theories.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)