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Space Science

How Would an Astronaut Falling Into a Black Hole Die? 412

Posted by Soulskill
from the probably-heart-attack dept.
ananyo writes "According to the accepted account, an astronaut falling into a black hole would be ripped apart, and his remnants crushed as they plunged into the black hole's infinitely dense core. Calculations by Joseph Polchinski, a string theorist at the Kavli Institute for Theoretical Physics in Santa Barbara, California, though, point to a different end: quantum effects turn the event horizon into a seething maelstrom of particles and anyone who fell in would hit a wall of fire and be burned to a crisp in an instant. There's one problem with the firewall theory. If Polchinski is right, then either general relativity or quantum mechanics is wrong and his work has triggered a mini-crisis in theoretical physics."
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How Would an Astronaut Falling Into a Black Hole Die?

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  • by Kenja (541830) on Friday April 05, 2013 @02:31PM (#43370869)
    Locate a black hole and start shooting monkeys at it! "Science can not progress without heaps [of monkeys]"
    • by Hentes (2461350) on Friday April 05, 2013 @02:38PM (#43370965)

      The problem is that we won't be able to observe what happens to them inside the event horizon. If you want to be sure, you have to go yourself.

    • by roc97007 (608802)

      That sounds like a youtube moment.

    • Locate a black hole and start shooting monkeys at it! "Science can not progress without heaps [of monkeys]"

      Isn't this how Planet of the Apes got started.... just saying... I, for one, welcome our new black hole traveling monkey overlords...

    • by TheLink (130905) on Friday April 05, 2013 @03:14PM (#43371471) Journal

      Blackholes might not be that uncommon.
      http://physicsworld.com/cws/article/news/2013/mar/15/micro-black-holes-could-form-at-lower-than-expected-energies [physicsworld.com]
      There are even some theories that some ball lightning could be due to blackholes:
      http://en.wikipedia.org/wiki/Ball_lightning#Black_hole_hypothesis [wikipedia.org]

      Imagine a tiny blackhole with literally tons of charged particles beyond the event horizon (which is not far away for a tiny blackhole) in close very high speed orbit around it. Those particles might still be affected by magnetic fields, and how about their gravitational effect on the blackhole itself?

      Perhaps some real physicists can explain what would happen in such a scenario.

  • We already know that QM and relativity can't both be true. Each theory is very good at predicting things in its realm, but they are mutually exclusive.

    • by Entropius (188861) on Friday April 05, 2013 @03:04PM (#43371329)

      This isn't true.

      QM and *special* relativity get along just fine. When you combine them in a simple way you get predictions like antimatter, the fine structure of the hydrogen atom, and so on. If you do this in a more detailed way, using quantum field theory, you get the fantastically accurate predictions of quantum electrodynamics, the theory of quantum chromodynamics that can't be solved with pen and paper but which still gives accurate predictions when done on supercomputers, and so forth.

      And there's nothing forbidding QM from playing nice with general relativity, either; we just don't know how it works yet. There are some models, like lattice quantum gravity, that seem quite promising.

      • And there's nothing forbidding QM from playing nice with general relativity, either; we just don't know how it works yet. There are some models, like lattice quantum gravity, that seem quite promising.

        Whatever happened to M theory (the successor to string theory)?

      • by Livius (318358) on Friday April 05, 2013 @04:31PM (#43372397)

        And there's nothing forbidding QM from playing nice with general relativity, either; we just don't know how it works yet.

        Translation: As currently formulated, at least one of quantum mechanics and general relativity is wrong, although like Newtonian mechanics or pre-relativistic optics, they will undoubtedly continue to be practical and very accurate approximations.

        We knew this as soon as quantum mechanics was developed.

    • We know no such thing. In fact both appear to be true, the problem being that we don't have an overarching theory that explains how that is so.

  • The astronaut dies of old age?

    • by Motard (1553251)

      Yes, because getting to a black hole will take a long time.

    • by Culture20 (968837) on Friday April 05, 2013 @02:51PM (#43371183)
      The other way around: The universe dies of old age around the astronaut and black hole.
      • by RoccamOccam (953524) on Friday April 05, 2013 @03:07PM (#43371373)
        There was an SF short story in which an interstellar alien being was psychically-linked with a human and was helping her team study a black hole. The alien is unable to escape the gravity well and is quickly destroyed. Unfortunately, for the human, the alien's time frame is different, so the human will experience its psychic scream for her entire life.
    • by jhol13 (1087781) on Friday April 05, 2013 @03:35PM (#43371719)

      This reminds me of the two unknowns: how can a black hole be created if the matter falling to it can never get there? The another one is of course: how can gravitons escape event horizon and attract anything?

      I think good theorists can answer both - I cannot either.

  • The smart money is no-firewall and complimentarity is bunkum.

    But I'm not smart, Polchinski is.

  • by The Grim Reefer (1162755) on Friday April 05, 2013 @02:38PM (#43370959)
    Hell is in the black hole. And pray you don't go there with a psychotic red robot.
  • Bad headline (Score:5, Insightful)

    by SirGarlon (845873) on Friday April 05, 2013 @02:41PM (#43371015)

    TFA is an interesting article about a physicist apparently discovering an inherent contradiction between general relativity and quantum mechanics. The "black hole" stuff is really just the context that led to the apparent contradiction: the real issue is much deeper than that. It's depressing that the real underlying hypothesis isn't considered newsworthy, and the editor feels the need to lead with the "black hole" stuff.

    • Re:Bad headline (Score:5, Interesting)

      by bluefoxlucid (723572) on Friday April 05, 2013 @02:44PM (#43371077) Journal
      Polchinski is actually correct, sort of. Everything approaching a black hole is being compressed; you'd be exposed to the burning energy of a hundred thousand million thermonuclear explosions before reaching the event horizon.
      • Misleading (Score:2, Insightful)

        by phorm (591458)

        The whole "what would happen to an astronaut" is the misleading sensationalist that's been pollution this site lately. It seems they're really going from "News for Nerds" to "Fox News for people who may buy computer and sciency stuff from places like Thinkgeek" (though thinkgeek is awesome BTW) in order to gain bigger audience.

        End result is it drives away the core audience that used to make this site awesome, as it dumbs down the really interesting science parts beyond recognition.

    • That contradictions exist between Newtonian physics, relativity, and quantum mechanics is pretty much old news.

  • by roc97007 (608802)

    That would certainly change the end of the movie [imdb.com].

  • by pezpunk (205653) on Friday April 05, 2013 @02:43PM (#43371063) Homepage

    i agree the reversed lower playfield can be a bit disorienting at first, but let's not get melodramatic -- since there are no outlanes in the gravity well, a quick SDTM drain is really the only way to die down there, and completing either bank of drop targets opens the re-entry gate anyway.

  • Shouldn't we use a convicted murderer or something?
    • by pezpunk (205653) on Friday April 05, 2013 @02:50PM (#43371157) Homepage

      well, technically, wouldn't the convicted murder BECOME an astronaut by definition the moment we shot him into space?

      slashdot is really provoking the deep questions today.

    • by Culture20 (968837)

      Shouldn't we use a convicted murderer or something?

      They behave differently in a vacuum.

    • "Just settle down out there, you'll get your $20"
      ~Cave Johnson

    • by hawguy (1600213)

      Shouldn't we use a convicted murderer or something?

      I think there would be plenty of volunteers for a one-way trip to a black hole -- volunteers more willing to make scientific observations than a death-row inmate forced to go.

      Besides, what if the inmate banished from earth finds himself released by an atomic shockwave from a planet that his prison-ship flies near and he goes to that planet and finds that he has superpowers granted by the planet's sun, and he wreaks havoc on that planet as a super-villan until someone on the planet with super-powers to mat

  • At this point all we have in conjecture as actually studying what would happen is for all intents and purposes impossible. Are you crushed, burned alive by everything else, toasted by radiation, spaghettified, or some other horrible fate?

    The only thing that we /really/ know is that any possible fate you would have from falling into a black hole would be painful. Unless you are killed so quickly your body never has a chance to transmit the signals for excruciating pain. The bottom line is that we really don'

  • My theory (Score:5, Funny)

    by Algae_94 (2017070) on Friday April 05, 2013 @02:46PM (#43371101) Journal
    Unicorns would stampede the astronaut as he enters the event horizon. There's one problem with the unicorn theory. If I'm right, then either general relativity or quantum mechanics is wrong.
    • by alphatel (1450715) *

      Unicorns would stampede the astronaut as he enters the event horizon.

      I think we can all agree the astronaut would die.

  • by HermDog (24570) on Friday April 05, 2013 @02:50PM (#43371153)
    try to avoid falling into a black hole
  • I once read that if the black hole is big enough tidal forces will be minimal and you can actually cross the event horizon alive.

    This theory has some merit as the universe itself is a black hole from a certain point of view.

  • He'd be dead before got close to the thing.

  • Due to the tidal grdient across your length. A large BH would have a midel tidal gradient. I dont know the size, but I think its over a trillion solar masses.
  • Infinite density = zero size and something with zero size no longer exists. If something has a presence in spacetime it will have some form of dimension. You can't have "something" that isn't actually there.

    • by Sardak (773761)
      This has always bugged me, too. If, for example, you take the black hole at the center of our galaxy, assume all of its mass is located in a singular location and that it is roughly a sphere with a diameter of one Planck length, you get a density of about 3.88 * 10^141 kg/m^3. Very high, but a far cry from infinite.
  • ... He'd just red-shift more and more forever
    • by Jherico (39763)
      This depends on the size of the black hole. The larger the black hole, the smaller the tidal forces at the actual event horizon, in which case you're correct, he just seems to slow down and redshift from an outside observer. However, for a small enough black hole he'll be ripped apart and quite dead long before he reaches the event horizon. If it's small enough to have a hot accretion disk (whether the disk is there or not).
  • by fahrbot-bot (874524) on Friday April 05, 2013 @03:07PM (#43371371)

    Umm... He's a string theorist, so...

    Listen to Zombie Feynman kids: Unscientific [xkcd.com]:

    • "I hunger for Braaaaaiiiinns!"
    • Uh, try the Physics lab next door.
    • "I said brains. All they've got are string theorists."
  • The astronaut would die of starvation or hypoxia long before they got to the Black Hole, given that the farthest we've sent an astronaut is 250,000 miles (a bit more than one light-second), and the nearest black hole is 1600 light years away, or 5E+10 times as far.

  • by Fuzzums (250400) on Friday April 05, 2013 @03:55PM (#43371991) Homepage

    First answer: Alone.

    But I saw this rather interesting video of a lecture by Leonard Susskind : http://www.youtube.com/watch?v=pf0D8A0jRiY [youtube.com]
    It will probably not answer your question, but it's about black holes and they're very cool! Or hot. Depending on the observer ;)

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