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Physicists Theorize Out How To Retrieve Information From a Black Hole (sciencemag.org)

Posted by samzenpus on from the there-and-back-again dept.

sciencehabit writes: Black holes earn their name because their gravity is so strong not even light can escape from them. Oddly, though, physicists have come up with a bit of theoretical sleight of hand to retrieve a speck of information that's been dropped into a black hole. The calculation touches on one of the biggest mysteries in physics: how all of the information trapped in a black hole leaks out as the black hole 'evaporates.' Many theorists think that must happen, but they don't know how.

4 of 82 comments (clear)

  1. Easy by penguinoid · · Score: 4, Funny

    Ask a politician or CEO or salesman. They routinely pull information out of a "black hole".

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    Don't waste your vote! Vote for whoever you want, unless you live in a swing state it won't matter anyways
    1. Re:Easy by davester666 · · Score: 4, Insightful

      It's more of a brown hole. Many people refer to it, as well as the politician/ceo/salesman, as an "ass" or "asshole".

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  2. Reservations re Hawking radiation by Black+Parrot · · Score: 3, Interesting

    Ignorant amateur here. ISTM that if a virtual pair appears straddling the event horizion, the one that gets away never was inside the black hole to begin with, and thus would not carry away any matter or energy. Isn't the black hole just working as an engine to extract matter/energy from the vacuum near the event horizon? Half of which goes in, making the BH bigger, and half of which escapes to the external universe.

    In the unlikely event that that conception is correct, it would be interesting to think about what happens to the vacuum near the event horizion. Does it get depleted of its vacuum energy, or is it an infinite source? If depleted, does vacuum energy flow in from other nearby vacuum to replenish it?

    Is the vacuum inside a black hole anything like the external vacuum?

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    1. Re:Reservations re Hawking radiation by maugle · · Score: 5, Informative

      Not quite. The virtual pair has a net energy of 0, and therefore isn't really "extracting" anything from the vacuum. If the pair weren't straddling a black hole, they'd recombine and disappear and nothing would happen. However, when one member of the pair is sucked into a black hole while the other particle escapes, the escaping particle must have a greater-than-zero amount of energy. Because of that, and the requirement that the two particles balance each other out, the black hole has necessarily absorbed a negative-energy (not negatively-charged, mind you, actually negative energy) particle, causing the black hole to shrink ever so slightly. Basically, while the particles originally came from vacuum, the energy was taken from the black hole.

      Also, to an external observer this process looks exactly the same as if the black hole itself was slowly emitting particles and shrinking away. And if the black hole is emitting particles, we can use that to determine something about its internal state.