Even Stephen Hawking sometimes turns out to be wrong. Who better to put him right than himself?
Are black holes bald or hairy? On that strange and esoteric question may hang the future of the universe’s past. The present, the past and the future are all connected by physical laws, a phenomenon called “causal determinism”. With complete information about a system’s present, it ought therefore be possible to determine all its past and future states. In theory, that applies to any system, up to and including the entire universe.