The celebrated physicist has a new theory about where lost information ends up after being sucked into a black hole, a place where gravity compresses matter to a point where the usual laws of physics break down.
In a public lecture in Stockholm, Sweden, Prof Hawking said: “If you feel you are in a black hole, don’t give up. There’s a way out.” He said he had discovered a mechanism “by which information is returned out of the black hole”.
He was speaking at the KTH Royal Institute of Technology, where the Nordic Institute for Theoretical Physics (Nordita) is hosting the Hawking Radiation Conference dedicated to examining the mystery of the “information paradox” – a conundrum concerning what happens to things swallowed by black holes.
Information about the physical state of something disappearing into a black hole appears to be completely lost. But according to the way the universe works, this should be impossible. Even information falling into a black hole ought to end up somewhere.
According to Hawking, it does – in one of two ways. Either it is translated into a kind of “hologram” on the edge of the black hole, or it breaks out into an alternative universe.
In his lecture, reported in a blog from the KTH Royal Institute of Technology, he said: “The existence of alternative histories with black holes suggests this might be possible. The hole would need to be large and if it was rotating it might have a passage to another universe. But you couldn’t come back to our universe. So although I’m keen on space flight, I’m not going to try that.
“The message of this lecture is that black holes ain’t as black as they are painted. They are not the eternal prisons they were once thought. Things can get out of a black hole both on the outside and possibly come out in another universe.”
Hawking is director of research at Cambridge University’s department of applied mathematics and theoretical physics.
• This article was amended on 27 August 2015. An earlier version said the KTH Royal Institute of Technology was hosting the conference.