Professor Stephen Hawking has proposed a new solution for how information might be able to escape a black hole.
The problem has confounded physicists for decades; quantum mechanics says when objects fall beyond the event horizon — the boundary where even light cannot escape from a gravity well — the information about that object must survive, but general relativity says that it must be destroyed.
Known as the information paradox, it is one of the central mysteries of modern physics and its solution could potentially hold the key to reconciling the physics of the very small (quantum) with that of the very large (relativity).
Now Hawking thinks he has a solution: the information about objects falling into black holes can escape because it doesn’t actually make it inside.
“I propose that the information is stored not in the interior of the black hole as one might expect, but on its boundary, the event horizon,” Hawking told the Hawking Radiation Conference audience in Stockholm, Sweden. “If you feel you are in a black hole, don’t give up,” he said.
Hawking made his name in the 1970s by proposing how quantum fluctuations in black holes could allow photons to be emitted from the singularity and escape the black hole. In 2004 he reversed his initial assumption that this matter did not contain information about a black hole, arguing it was possible for information to escape.
His new idea, which he worked on with Malcolm Perry and Andrew Strominger, is one method by which that process could occur. Hawking proposes that as information about particles moves through the event horizon it is translated into a 2D hologram, and remains on the edge of the event horizon. In this way it can survive without violating general relativity. “The idea is the super translations are a hologram of the ingoing particles […] Thus they contain all the information that would otherwise be lost.”
This doesn’t meant it would be possible to send a message from inside a black hole. “The information about ingoing particles is returned, but in a chaotic and useless form,” he said. “This resolves the information paradox. For all practical purposes, the information is lost.” But it would mean black holes are not the inescapable pits of doom they were once thought to be — things can get in, and out — but they might end up in another universe when they finally do escape.
“The existence of alternative histories with black holes suggests this might be possible,” Hawking said. “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.”