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Stephen Hawking Presents Theory On Getting Information Out of a Black Hole

An anonymous reader writes: Physicist Stephen Hawking claims to have figured out a way for information to leave a black hole. He presented his theory today at the KTH Royal Institute of Technology in Stockholm. Scientists have struggled with the black hole information paradox for years, and Hawking thinks this new theory could be a solution. He said, "I propose that the information is stored not in the interior of the black hole as one might expect, but in its boundary, the event horizon." Put in layman's terms, "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." Information can leave the black hole via Hawking radiation, though it will be functionally useless. Hawking worked with Cambridge's Malcolm Perry and Harvard's Andrew Stromberg on this theory.

17 of 172 comments (clear)

  1. Leonard Susskind. by Anonymous Coward · · Score: 5, Insightful

    "Hawking's new idea is that the information doesn't make it inside the black hole at all. Instead, it's permanently encoded in a 2D hologram at the surface of the black hole's event horizon".

    Uh, isn't that basically Susskind's idea? The holographic principal and all.

    1. Re:Leonard Susskind. by MouseTheLuckyDog · · Score: 3, Informative

      I don't know if that is Suskind's view. Some physicists certainly hold the view that you do not see inside the black hole and what an external observer thinks of as the interior is really the surface.

      That however is not the holographic principle. The holographic principle stats that there is an equivalence of certain 3 dimension gauges theories with four dimensional quantum gravity.

  2. Much rejoicing by MouseR · · Score: 5, Funny

    He doesn't look all too terribly excited about it.

    1. Re:Much rejoicing by Oligonicella · · Score: 3, Insightful

      I missed the bulletin were you were appointed laughter arbiter.

    2. Re:Much rejoicing by meta-monkey · · Score: 3, Funny

      How do I apply for a laughter license? Is it like the DMV, or do they just come from you personally? I'd love to get one from you, but I'll need a step ladder given the height of your horse.

      --
      We don't have a state-run media we have a media-run state.
  3. So now we have a new paradox... by bobbied · · Score: 4, Interesting

    Hawking in all his brilliance has produced a new paradox trying to solve another? How's that help anything? This is re-arranging the deck chairs on the Titanic.

    So now we have information that's "useless" because we won't be able to unscramble it, but no information is lost? It's like saying that the information on my degaussed and melted down backup disk drive is *still* there, if I just knew how to reassemble it properly. That backup disk is just a pile of slag, the information it contained is gone. I'm sorry, that sure looks like we lost information to me... The net effect is the same as the information being lost, so I don't see how this stroke of genius helps the problem beyond moving the paradox to having the information preserved but unrecoverable by any possible means.

    Try again sir... You didn't solve anything here.

    --
    "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
    1. Re:So now we have a new paradox... by Anonymous Coward · · Score: 4, Interesting

      I think the point is that the information is there, but it would require a tremendous amount of energy to reassemble it, much more than, say, putting humpty-dumpty back together again. That's not a paradox.

      I'm not a physicist, but the holographic principle has been around for a long time; it's conjectures that a black hole is a 2-dimensional object--there's no space on the other side of the event horizon, the event horizon _is_ the blackhole. And others have suggested that information can leak via fluctuations at the boundary. Any physicists care to distinguish what's truly novel with this new theory?

    2. Re:So now we have a new paradox... by Anonymous Coward · · Score: 4, Informative

      You're getting hung up on the word information. It's a term of art in this context. The physics is relying on an an equivalency between information content and energy. In many cases it's easier to model blackholes from an information-theoretic context. That is, bits go in, bits come out. It's like the word entropy--the same word is used to describe seemingly different phenomena regarding both information and energy, but really it's the same phenomenon.

      Just replace "information" with "energy" and it will make more sense. By information coming out, they mean energy is coming out. And energy, of course, is that thing which allows us to perform useful work.

      Why does this matter? Well remember that the laws of thermodynamics say that entropy is always increasing in a closed system. If blackholes sucked entropy out of the universe, the implications are problematic, for reasons I don't really understand, and that aren't resolved by simply stating the obvious--blackholes are part of the universe.

      Rather than calling this the "entropy" paradox, though, it's called the "information paradox". It's just easier to reason about it when you think in terms of bits.

      Also, your original assertion is incorrect. Imagine that we burn a tiny piece of paper with some secret information on it. Theoretically with enough cameras, recorders, and other equipment we could reconstitute the secret by tracking every scrap of carbon and every other molecule. But it requires tremendous resources. The resources needed scale as a high-order geometric function of the size (or complexity) of the thing we burned. If we thoroughly burnt a book, there wouldn't be enough resources on earth, perhaps the solar system, to build the machines needed to track and reconstitute the information.

      Because the universe is finite, and the information released by a blackhole so "scrambled", there's not enough energy in the entire universe to unscramble it. As large as the universe is, it's no match for math. But we _know_ the information is there because the energy emitted can be used to perform work.

    3. Re:So now we have a new paradox... by Bengie · · Score: 3, Informative

      Being able to reassemble it is not the point, it's that you can re-wind time and get the information back out. With the normal idea of a blackhole, even if you could rewind time, you couldn't get the information back out.

    4. Re:So now we have a new paradox... by Xyrus · · Score: 3, Insightful

      You don't understand the concept and made ASSumptions based on a generalized analogy that isn't even wholly correct, then proclaim that he's an idiot.

      Are you running for office?

      Regardless, how about a different analogy that might might make this more clear.

      You have an egg. You drop it. The egg hits the floor. It vanishes. Do you still have an egg? Nope.

      You have an egg. You drop it. The egg splatters on the floor. Do you still have an egg? Yep.

      The former is how black holes were thought to work. The problem is that if black holes really worked that way it would cause some rather odd things to occur. We haven't observed these really odd things, which implies that black holes don't operate that way.

      The latter is how they operate according to the new work. The egg may not be in the same form, but it didn't "vanish". You didn't "lose" anything. It's just in a different form. Sure, it may not be anything more than a mess on your floor. It may not be useful for anything other than a Fido snack. But it doesn't change the fact that the egg is still there.

      --
      ~X~
  4. Of course it never gets past the event horizon. by Rei · · Score: 5, Informative

    A particle falling into a black hole never perceives itself as having moved past an event horizon, as an apparent event horizon recedes before it. The horizon keeps receding in the direction of the "singularity" until it's torn apart on the way in.

    An external observer never perceives a particle falling past the so-called "true" horizon; it perceives the falling object's time as slowing down to a virtual stop at the event horizon.

    Both of these views are logically consistent under a simple constraint: nothing ever passes an event horizon, and there's no such thing as a "true" horizon, only apparent horizons. The outside observer's view of "truth" should be given no more precedence as being reality than the infalling observer's perception.

    The same nothing-moves-past-the-event-horizon rule must apply to particles falling into the black hole as it's forming: they never get to reach a "singularity" either. Meaning nothing is ever in a singularity state, even that which formed the black hole itself.

    As a black hole evaporates, its mass drops and its event horizon moves inward. Hence, an outside observer will perceive more of an infalling particle's progress inward, as if time is slowly being released. The infalling particle perceives no wait, just a continuous fall. Since the outside observer is seeing the infalling particle's time as moving many, many orders of magnitude slower, then for the two reference frames to be logically consistent, the amount of black hole power output perceived by the outside observer must be perceived by the infalling particle to be many, many orders of magnitude more intense. Hence it's far from black to the infalling particle, rather an intense source of radiation, growing ever more violent as the particle falls further in.

    In short, all of this implies that black holes, to an outside observer, are basically a spot where time slows to a near stop, slowly leaking it out as they radiate away. To an infalling observer, he's just falling into a collapsing star that grows ever more radiatively intense as it collapses. The infalling particle, like everything else that falls into the black hole in the collapse, is blown apart by the intense radiation. But no special rules occur, no loss of information - and no singularity.

    Or whatever, what do I know ;)

    --
    Stale pastry is hollow succor to one who is bereft of ostrich.
    1. Re:Of course it never gets past the event horizon. by AthanasiusKircher · · Score: 3, Informative

      A particle falling into a black hole never perceives itself as having moved past an event horizon, as an apparent event horizon recedes before it. The horizon keeps receding in the direction of the "singularity" until it's torn apart on the way in.

      This isn't true. Particles do in fact pass the event horizon in finite time (as judged in their own time frame). In fact, for very large black holes (tens of thousands of solar masses), it would easily be possible to pass the event horizon without experiencing tidal forces strong enough to rip you apart... in finite time.

      An external observer never perceives a particle falling past the so-called "true" horizon; it perceives the falling object's time as slowing down to a virtual stop at the event horizon.

      While this is sort of true, the idea of an external observing viewing an astronaut "frozen in time" just above the event horizon is just not true in any practical sense.

      What you'd actually observe if you watched someone fall into a black hole is the light from that person exponentially getting dimmer and fading out basically completely in finite time (i.e., probably within a fraction of a second for reasonable sized black holes). Yes, theoretically you can get a photon emitted and taking years or centuries to reach an external observer, but the amount of emitted light decays exponentially fairly quickly -- so as an external observer you'd actually see someone basically "disappear" at the event horizon in finite time (and fairly quickly actually). (For some details and a sample calculation with explanation, see here.)

      Both of these views are logically consistent under a simple constraint: nothing ever passes an event horizon, and there's no such thing as a "true" horizon, only apparent horizons. The outside observer's view of "truth" should be given no more precedence as being reality than the infalling observer's perception.

      Well, since both of your "views" are sort of wrong (or, well, at least misleading), I'm not sure the rest of your explanation should be taken as true.

      Also, the problem is notions of simultaneity and where time and space is in black holes is quite complex when you try to compare observers in general relativity -- basically, you really can't come up with objective metrics that will satisfy notions of simultaneity for observers except in a local sense. So talking about whether a black hole "has formed" or where the event horizon "is" at a particular moment of time becomes quite complicated when you start to involve "external" observers. (For some details, see here for a bit of an explanation.)

      Anyhow, there's lots of debate going on with Hawking about what exactly goes on with black holes (and information), but my point is that trying to apply simple intuition to general relativistic effects around black holes is pretty much destined to fail, or at least lead to a lot of misunderstandings.

  5. Also known as ... by PPH · · Score: 5, Funny

    ... optimizing queries for Oracle.

    --
    Have gnu, will travel.
  6. In related news... by fahrbot-bot · · Score: 4, Funny

    Put in layman's terms, "this jumbled return of information was like burning an encyclopedia ...

    Millennials ask, "how would you burn Wikipedia?"

    --
    It must have been something you assimilated. . . .
    1. Re:In related news... by bsolar · · Score: 4, Funny

      In a flamewar.

  7. Re:so? by meglon · · Score: 3, Insightful

    You know why there isn't a Bruce Lee meme like the Chuck Norris meme? Bruce Lee wasn't a joke.

    --
    Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
  8. It's easy by wonkey_monkey · · Score: 4, Funny

    Stephen Hawking Presents Theory On Getting Information Out of a Black Hole

    You rough it up a little, shine a bright light in its face and ask it where it stashed the loot. You could also play good astrophysicist/bad astrophysicist.

    --
    systemd is Roko's Basilisk.