Stephen Hawking has said black holes could be one way passages to other universes while offering an explanation to the information paradox – a conundrum about what happens to information about objects that fall into black holes.
The problem has troubled physicists for a long time – quantum mechanics says information about an object that falls into an event horizon must survive, while general relativity says it must be destroyed.
However, Hawking says he might have the answer. He says the information about objects in black holes cannot escape because it never makes 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. If you feel you are in a black hole, don't give up," Hawking told a conference in in Stockholm.
He was speaking at the Hawking Radiation Conference at the KTH Royal Institute of Technology. This latest idea was a collaboration with fellow physicists Malcolm Perry and Andrew Strominger. He was revisiting the idea that it is possible for information to escape black holes.
Hawking suggests that information about objects is translated to a 2D hologram as it passes through the event horizon, remaining on the edge. This means it can survive while still adhering to general relativity – these holograms act as "super translations" and "contain all the information that would otherwise be lost". "The information about ingoing particles is returned, but in a chaotic and useless form. This resolves the information paradox. For all practical purposes, the information is lost."
However, he also said objects falling into black holes are not necessarily lost forever as they could end up in another universe: "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.
"The message is ... 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."