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How an Astronaut Falling Into a Black Hole Would Die Part 2 263

Posted by samzenpus
from the unlikeliest-of-endings dept.
First time accepted submitter ydrozd writes "Until recently, most physicists believed that an observer falling into a black hole would experience nothing unusual when crossing its event horizon. As has been previously mentioned on Slashdot, there is a strong argument, initially based on observing an entangled pair at the event horizon, that suggests that the unfortunate observer would instead be burned up by a high energy quanta (a.k.a "firewall") just before crossing the black hole's event horizon. A new paper significantly improves the argument by removing reliance on quantum entanglement. The existence of black hole "firewalls" is a rare breakthrough in theoretical physics."
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How an Astronaut Falling Into a Black Hole Would Die Part 2

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  • Pay wall crap. (Score:2, Informative)

    by Anonymous Coward

    The only new information cited is behind a $25 pay wall. Kill it with fire.

  • Non-paywalled link (Score:5, Informative)

    by NeverWorker1 (1686452) on Sunday October 27, 2013 @04:31PM (#45253215)
    From the arxiv: http://arxiv.org/pdf/1307.4706.pdf [arxiv.org]
  • From a surfeit of "would"s, apparently.

    • by 91degrees (207121)
      It's the gravity. You're actually seeing one "would", but the gravity bends light around that you see it again in a different apparent position.
    • by SIR_Taco (467460)

      It would seem that verbs enter a black hole, temporarily escape, and are again swallowed by said black hole.

  • I wonder how you setup a static nat on a Black Hole...

    hmmm

  • by Kahlandad (1999936) on Sunday October 27, 2013 @04:34PM (#45253243)

    It's not the fall that kills you, it's the sudden ...oh wait, it IS the fall that kills you.

  • by PolygamousRanchKid (1290638) on Sunday October 27, 2013 @04:45PM (#45253313)

    The funny thing is . . . if someone announced a space program to toss an astronaut down a black hole . . . there would be plenty of volunteers for the mission.

  • The gravitational force on physical objects would squeeze his body to a spaghetti far before the event horizon.

    Hopefully quickly.

    • by scorp1us (235526)

      I don't agree. If you assume he is 1.5 meters high, then the relative forces at the event horizon would be minimal, remember it is over r^2. The Schwarzschild radius as it is called. If you took our sun's mass and converted to to black hole densities, it would be r of 2,950 m. Now, the force at this even horizon would then be 2950m and 2951.5m Find the tidal forces over that 1.5 meters. It's not a whole lot. However you start to get into time dilation, again over 1.5 meters it isn't that much.

      • Roche limit describes the maximum characteristic length of a gravitationally bound body in orbit of another object based on gravitational gradient. Basically, no larger objects (of similar density) are expected to form at any particular orbit level. It's not a perfect fit for something that is chemically bound, but you can still derive a form of it using other physical constants of the right units. Yield strength, for instance.

      • by amaurea (2900163) on Sunday October 27, 2013 @07:35PM (#45254413) Homepage

        Find the tidal forces over that 1.5 meters. It's not a whole lot. However you start to get into time dilation, again over 1.5 meters it isn't that much.

        Really now. And how did you arrive at it not being "a whole lot"? Let's insert some numbers, shall we? The mass of the sun is about 2e30 kg. Its Schwartzschild radius is, as you say, 2950 km. The acceleration according to Newtonian gravity at that point is 1.5211095e13 m/s^2. 1.5 meters further out (that's a short astronaut, by the way), the acceleration is 1.5195660e13 m/s^2. The difference is 2.057e10 m/s^2. I.e. roughly 2 billion g. Most of us would find it hard to stay together under such tension, but I guess you're made of stronger stuff!

        (Of course, Newtonian gravity doesn't work very well for such strong gravitational fields. But it's enough to tell you that you're in a lot of trouble.)

        • by scorp1us (235526)

          Thanks. I must have messed something up with the exponents. 2 billion g is a lot of G.

        • by sfm (195458)

          With a much more massive black hole, the radius increases so your 2 billion g's goes down to a
          "much more comfortable" several 10's of millions of g's

  • by mTor (18585) on Sunday October 27, 2013 @04:57PM (#45253383)

    Black hole firewalls don't really exist.

    Here's a summary:

    http://arxiv.org/abs/1310.6334 [arxiv.org]

    and the long paper:

    http://arxiv.org/abs/1310.6335 [arxiv.org]

    Resolving the issue.

    In short, the black hole paradox doesn't exist and can be explained.

    Motl has a really nice summary as well:

    http://motls.blogspot.com/2013/10/raju-papadodimas-isolate-reasons-why.html [blogspot.com]

  • I'm sort of lost here. Granted I know very little about this subject, but what I do know is black holes are far away. And entangled pairs are really fucking small. So how the hell can we see entangled pairs at the event horizon of a black hole? Seems to me if we can see stuff that small, that far away, finding planets similar to ours would be easy, since they are very very very much bigger.

    • I don't think we can see anything at all, at present, other than their gravitational effect. For example, the mass of something at the center of our galaxy can be determined by the orbits of some stars zipping around it, and the size of those orbits put an upper bound on that something's diameter.

      If we were nearer we should be able to see something similar to black body radiation, assuming we weren't blinded by the material swarming around it and falling in.

      Interestingly, some physicists think that we migh

    • by mcgrew (92797) *

      This doesn't have anything to do with telescopic observation, this has to do with math.

      • by Nyder (754090)

        This doesn't have anything to do with telescopic observation, this has to do with math.

        Ah, math, the answer to everything.

        So then basically they are just guessing and really have no idea at all if they are right or not. Figures.

        • by gl4ss (559668)

          they're guessing if the information could theoretically pass through.. or rather not guessing but trying to reason it could.

  • But would he chuck wood?
  • We can cloak light. We can cloak magnetism. Both recent developments, both recently far fetched science-fiction. As a thought experiement at least, what if we could cloak an object - perhaps even one containing a human - from gravity and then send that object on a trajectory into a black hole. This assumes that the high levels of radiation and firewall have also been overcome.
  • Sorry guys, it's not romantic at all,

    the astronaut would die or be dead anyway, if the black hole is

    a.) in absolute Vacuum, nerve destruction by hard gamma radiation+particle radiation, even his spacesuit would not protect him

    Why ? -> gamma radiation black body radiation, continuum source -> temperature -> high temperature -> short wave lengths -> hard gamma radiation
    Where comes the radiation from, his own atoms off course !

    Absolute Vacuum + Astronaut = not a vacuum anymore.

    b.) in interstella

    • this is rediculous

      I thought you said it was radiation.

    • The thought experiment is about what peculiarity the black hole death holds, so give him a perfect radiation proof suit and try again.
      Or, try this question instead. After dying of radiation, what happens to the body? The context to this question, fundamentally, is whether a person would be shredded or squished, or just fall forever, or maybe hit a wall of fire and burn up. Dead or alive.

  • And how would Slashdot would look if would editors would edit?
  • Please remember that there is basically no experimental evidence for any of this speculation. No. Experimental. Evidence. There is barely evidence for general relativity type black holes*, no evidence at all for Hawking radiation, and thus of course no evidence for the theoretical infrastructure built on top of Hawking radiation.

    And, plenty of (theoretical) papers have looked [arxiv.org] at this and come to alternate [arxiv.org] conclusions [arxiv.org].

    I suspect that when we actually do start experimenting with black hole event horizons dire

  • If someone falls into a black hole, is their soul stuck there for the 62 zillion years it takes the black hole to evaporate?

    If you pushed someone into a black hole, could you beat the murder rap by pointing out that he still hadn't finished falling in, from the jury's reference frame?

    If you modified Shrõdinger's experiment so that the decay of an atom dropped the cat into a black hole rather than gassing it, then put a cat in the box to create a superposition of "the cat is in the black hole" and "the

  • ... than to be an adventurer who is the first to enter a black hole.

    *Note: Yes, horrible Skyrim joke reference that is completely out of date... but someone had to say it... (grin)

    • by Mishotaki (957104)
      I was an astronaut going right into a black hole once... but then I took an arrow to the knee...
  • There are so many things wrong with this article. First you'd be torn apart by tidal forces. Long before you got anywhere near it. If you somehow survived that, then time would slow as you approached. The wavelength of light would stretch due to time dilation, and the light hitting you from stars in the sky would shorten, so much so that you'd be roasted by high energy radiation. Lastly, it would take a very very very long time to actually reach the event horizon. As time slowed the victim would likely see

  • I always assumed the astronaut would be ripped apart by tidal forces long before reaching the event horizon.

  • The crappy grammar would kill him before he even would got there.

  • The astronauts freeze dried ice-cream would come through intact. Didn't you ever wonder why the stuff in the museum seems like it's been around for trillions of years?

  • The existence of black hole "firewalls"...

    This is the firewall I have been wanting for my home LAN.

    But I'm guessing it may be tricky to implement without sucking everything out of my network, including me...

  • Launch a suitably instrumented satellite into orbit around earth. Crank up the LHC, creating a small black hole. This will rapidly consume the earth. Since the mass of this black hole would be the same as that of the earth, the satellite's orbit would not be affected. The satellite could then make numerous measurements of phenomena occurring at the event horizon.

    OK, repeatability would be a problem.

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