Posted by This has been all over my inbox since the press release came out yesterday; it’s been on slashdot (thanks Brian), it’s been at space.com, and there’s a mediocre writeup on Universe Today. What’s the big news? Black Holes don’t destroy information after all!
What is this whole information thing, anyway? Take a look at all the normal stuff in the Universe: photons, protons, neutrons, and electrons, for example. They have lots of different properties each. They move around one another, they get bound and unbound from one another, they exert forces on one another, etc. They’re aware of one another, and they interact with one another, and they have many properties, both intrinsic and extrinsic. And when they come together, they make complex things, like atoms, which contain even more information than the individual particles do on their own:
But when you put all of this stuff into a black hole, all of this information seems to disappear. Black holes have only three properties: mass, charge, and spin. Everything else, all the information you put into it, seems to disappear. Doesn’t matter whether you put a bunch of neutrons in, or a bunch of human beings in: to a black hole, they’re the same things. Black holes don’t remember quantum numbers, they don’t remember how many quarks or electrons you put into it. All they care about is mass, charge, and spin.
Or so the story goes. That’s what Stephen Hawking has been saying for years, leading to his famous information paradox about black holes.
Well, it’s a paradox no more! A team at Penn State, led by Abhay Ashtekar (who’s pretty famous for his work on trying to formulate a quantum theory of gravity), has shown how all of that “lost information” can be recovered. The catch?
It means that space-time is not a continuum.
Instead, on the smallest scales, it has to actually be discrete, like little “chunks” of space-time strung together to create a giant mosaic.
The reason for this is that without a continuum, there can’t be any such thing as a singularity. Here’s what Ashtekar had to say about it:
Information only appears to be lost because we have been looking at a restricted part of the true quantum-mechanical space-time. Once you consider quantum gravity, then space-time becomes much larger and there is room for information to reappear in the distant future on the other side of what was first thought to be the end of space-time.
Wow. Now this hasn’t been verified or even published yet (May 20th, in Physical Review Letters), but this is really ground-breaking! Have a great weekend, folks, and don’t forget to swing on over to this week’s Carnival of Space at Altair VI, where you can read about lots of interesting stuff, including how to avoid Armageddon from incoming asteroids!
May 16, 2008
May 16, 2008
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April 11, 2009
