On Tuesday, renowned physicist Stephen Hawking presented his new theories on black holes to a gathering of esteemed scientists and members of the media at KTH Royal Institute of Technology in Stockholm. Hawking focused on something called the information paradox, an aspect of black holes that has been puzzling scientists for years. Basically, the paradox involves the fact that information about the star that formed a black hole seems to be lost inside it, presumably disappearing when the black hole inevitably disappears. However, according to how the universe works and what physicists believe, these things cannot be lost. But where does the information go when the black hole that’s absorbed goes down the drain?
Black holes look like they ‘absorb’ matter. Every time a star falls into a black hole, it seems like the star is completely lost — but according to the basic laws of physics, that’s not possible. Matter and information can’t really disappear. And black holes are no exception.
So what happens if you fall in a black hole?
“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,” Hawking says.
According to Hawking’s idea, the particles that enter a black hole leave traces of their information on the event horizon. When particles come back out–in a phenomenon called Hawking Radiation–they carry some of that information back out, preserving it…in a manner of speaking. “The information is stored in a super translation of the horizon that the ingoing particles [from the source star] cause,” he explained. “The information about ingoing particles is returned, but in a chaotic and useless form. For all practical purposes the info is lost.”
At Monday’s public lecture, he explained this jumbled return of information was like burning an encyclopedia: You wouldn’t technically lose any information if you kept all of the ashes in one place, but you’d have a hard time looking up the capital of Minnesota.
Here’s a video of Hawking’s lecture at KTH Royal Institute of Technology, Sweden