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Stuff that falls into a black hole is gone forever, right? Not so, says Stephen Hawking.

鈥淚f you feel you are in a black hole, don鈥檛 give up,鈥� he at a public lecture in Stockholm, Sweden, yesterday. He was speaking in advance of a scientific talk today at the being held at the KTH Royal Institute of Technology in Stockholm. 鈥淭here鈥檚 a way out.鈥�

You probably know that black holes are stars that have collapsed under their own gravity, producing gravitational forces so strong that even light can鈥檛 escape. Anything that falls inside is thought to be ripped apart by the massive gravity, never to been seen or heard from again.

What you may not know is that physicists have been arguing for 40 years about what happens to the information about the physical state of those objects once they fall in. Quantum mechanics says that this information cannot be destroyed, but general relativity says it must be 鈥� that鈥檚 why this argument is known as the information paradox.

Now Hawking says this information never makes it inside the black hole in the first place. 鈥淚 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,鈥�

鈥淏lack holes ain鈥檛 as black as they are painted鈥�

The event horizon is the sphere around a black hole from inside which nothing can escape its clutches. Hawking is suggesting that the information about particles passing through is translated into a kind of hologram 鈥� a 2D description of a 3D object 鈥� that sits on the surface of the event horizon. 鈥淭he idea is the super translations are a hologram of the ingoing particles,鈥� he said. 鈥淭hus they contain all the information that would otherwise be lost.鈥�

So how does that help something escape from the black hole? In the 1970s Hawking introduced the concept of Hawking radiation 鈥� photons emitted by black holes due to quantum fluctuations. Originally he said that this radiation carried no information from inside the black hole, but in 2004 changed his mind and said it could be possible for information to get out.

Just how that works is still a mystery, but Hawking now thinks he鈥檚 cracked it. His new theory is that Hawking radiation can pick up some of the information stored on the event horizon as it is emitted, providing a way for it to get out. But don鈥檛 expect to get a message from within, he said. 鈥淭he 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.鈥�

Last year Hawking made headlines for saying 鈥渢here are no black holes鈥� 鈥� although what he actually meant was a little more complicated, as he proposed replacing the event horizon with a related concept, an apparent horizon. This new idea is compatible with his previous one, which wasn鈥檛 really news to theoretical physicists, says of the Nordic Institute for Theoretical Physics in Stockholm, who attending Hawking鈥檚 lecture.

鈥淗e is saying that the information is there twice already from the very beginning, so it鈥檚 never destroyed in the black hole to begin with,鈥� she says. 鈥淎t least that鈥檚 what I understood.鈥�

More details are expected later today when one of Hawking鈥檚 collaborators Malcom Perry expands on the idea, and Hawking and his colleagues say they will publish a paper on the work next month, but it鈥檚 clear he is gunning for the idea that black holes are inescapable. It鈥檚 even possible information could get out into parallel universes, he told the audience yesterday.

鈥淭he message of this lecture is that black holes ain鈥檛 as black as they are painted. They are not the eternal prisons they were once thought,鈥� he said. 鈥淭hings can get out of a black hole both on the outside and possibly come out in another universe.鈥�