On Tuesday, famous theoretical physicist Prof Stephen Hawking presented his latest ideas on black holes – and the possible passage of information into alternative universes – at the Hawking Radiation Conference in Stockholm, Sweden.
Artist’s impression of a black hole and a normal star. Image credit: L. Calcada / ESO.
One of the most baffling questions facing a generation of physicists is what happens to the information about the physical state of things that are swallowed up by black holes?
Is it destroyed, as our understanding of general relativity would predict? If so, that would violate the laws of quantum mechanics.
According to a new idea proposed yesterday by Prof Hawking at KTH Royal Institute of Technology, black holes don’t actually swallow and destroy physical information. Instead, they store it in a 2D hologram. The presentation was made at the Hawking Radiation Conference, which was co-hosted by the Nordita institute and the University of North Carolina.
Everything in our world is encoded with quantum mechanical information. And according to the laws of quantum mechanics, this information should never entirely disappear, no matter what happens to it. Not even if it gets sucked into a black hole.
But Prof Hawking’s idea is that the information doesn’t make it inside the black hole at all. Instead, it’s permanently encoded in a two-dimensional hologram at the surface of the black hole’s event horizon.
As we understand them, black holes are regions of space-time where stars, having exhausted their fuel, collapse under their own gravity, creating a bottomless pit that swallows anything approaching too closely. Not even light can escape them, since their gravitational pull is so infinitely powerful.
“The information is not stored in the interior of the black hole as one might expect, but in its boundary – the event horizon,” Prof Hawking said.
He formulated the idea that information is stored in the form of what are known as super translations.
“The idea is the super translations are a hologram of the ingoing particles,” he explained.
“Thus they contain all the information that would otherwise be lost.”
“This information is emitted in the quantum fluctuations that black holes produce, albeit in chaotic, useless form. For all practical purposes the information is lost,” he said.
Prof Hawking also offered compelling thoughts about where things that fall into a black hole could eventually wind up.
“The existence of alternative histories with black holes suggests this might be possible,” Prof 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.”
