Inside a black hole, gravity is so intense that neither matter nor energy can escape. But in 1975, Cambridge physicist Stephen Hawking said that something does escape: random particles now known as “Hawking radiation.” So if black holes eat organized matter – chock-full of information – and then spit out random noise, where does the information go?
Hawking said it gets locked up inside as the black hole eventually evaporates, destroying the information in the process. Which creates a paradox. Because the rules of physics say information, like matter and energy, can’t be destroyed.
Hawking was confident. He convinced his super-genius counterpart at Caltech, physicist Kip Thorne, that he was right – but Thorne’s colleague John Preskill remained skeptical. So they made a bet: Hawking and Thorne said the singularity at the heart of a black hole destroyed information; Preskill said “nuh-uh.” Then, in 2004, Hawking reversed his position and decided that things that fall into a singularity aren’t lost; their information does leak out, though no one, except maybe Hawking himself, can explain why or how.
He presented Preskill with a baseball encyclopedia from which, presumably, information can be retrieved at will. Preskill accepted only grudgingly. “Even if you’re Stephen Hawking, it’s possible to be wrong twice,” he says.