Stephen Hawking came up with a way to escape a black hole, but it has a big snag

Whatever falls into a black hole never comes out again: It's trapped in a perfect prison, forever.

But Stephen Hawking, who already completely changed how we understand black holes once, just came up with another radical idea suggesting there is an escape method.

"If you feel you are in a black hole, don't give up," he told an audience at a public lecture in Stockholm on Aug. 24. "There's a way out."

Black holes are zones in space where gravity pulls so much that not even light can escape - hence the name "black hole." We're taught that anything that falls into a regular black hole gets shredded or stretched out and "spaghettified." (Gigantic black holes are different story.)

Scientists agree that black holes destroy objects, but have spent nearly half a century arguing about what black holes do to the information of objects. That information can include, as one example, the number, arrangement, and order of an object's atoms. It also might also describe the object's energy levels, trajectory, and so on.

Einstein's theory of general relativity says that all information must be destroyed in a black hole. But another, newer theory called quantum mechanics says it can't be destroyed.

Using both theories leads to conundrum known as the information paradox, and Hawking might have just come up with a solution: The information can escape because it doesn't actually make it all the way inside the black hole.

"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 said.

The event horizon is the rim around a black hole that acts as the point of no return - if you drift past the event horizon then you can't ever escape the black hole's grip. Hawking is saying the information about a 3D object that falls into a black hole might be stored on the event horizon in the form of a perfectly flat 2D hologram.

And if that information doesn't drift past the event horizon, then it might be able to escape. That's because Hawking's new theory builds on one of his old ideas about black holes.

About 40 years ago, Hawking proposed an exception to the rule that nothing escapes a black hole: Hawking radiation. The idea suggests that energy could escape black holes in the form of tiny particles of light that form at the edge of a black hole, thanks to a weird thing called quantum fluctuation:

Hawking's new idea is that this radiation, as it bleeds out of a black hole, might pick up an object's  information on its way out - thus providing a means of escape.

This doesn't mean we could rebuild a coherent message from anything trapped inside a black hole, though.

"The information about ingoing particles is returned, but in a chaotic and useless form," Hawking said. "This resolves the information paradox." Yet for all practical purporses, we've still lost the information.

We'll know more details when Hawking and his team publish the formal paper in a few weeks. We'll also learn more about an idea that Hawking only touches on: how something could escape a black hole but end up in a parallel universe.

"The message of this lecture is that black holes ain't as black as they are painted," Hawking said. "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."

You can watch a clip from Hawking's lecture below: