Did Stephen Hawking end decades-old debate on a black-hole paradox?

“If you feel you are in a black hole, don’t give up,” Stephen Hawking said to an audience at a public lecture in Stockholm, Sweden on Monday. “There’s a way out.”

Mr. Hawking was speaking to a group of mostly lay-people, in which he teased the idea that he may have another theory about black holes to bring to a close a 40 year-old debate known as the "black hole information paradox."

Black holes originate when massive stars collapse (or “die”) under their own gravity, creating a gravitational pull so strong that not even light can escape. Anything that falls into a black hole is believed to be destroyed by the immense gravity. But as New Scientist explains:

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 – that’s why this argument is known as the information paradox.

Before an audience of about three dozen foremost physicists at the Hawking Radiation Conference in Stockholm, Hawking said, "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 said.

If his theory proves true, Hawking will have solved a mystery that he and his colleagues have been debating since Hawking famously posited and proved, in 1974, that black holes emit radiation.

Among the physicists in Stockholm, there is already some doubt.

“I wouldn’t say the solution to the information paradox has been found because there are several competing ideas,” said Carlo Rovelli, physicist at the Aix-Marseille Universite in France, and an attendee, in an interview with the Wall Street Journal. “But Stephen being Stephen, everybody’s going to take it seriously.”

The Journal also notes that Gerard 't Hooft of Utrecht University, winner of the 1999 Nobel Prize in physics who was also at the conference, had presented a similar idea in 1996.

"I claim he is now where I was 20 years ago," he told the Journal. "If he announces this as a new idea, I won't be thrilled."