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Science

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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  • by TrollstonButterbeans (2914995) on Sunday October 27, 2013 @03:45PM (#45253309)
    I love how we treat blackholes specially.

    The escape velocity of a neutron star is about 1/3 the speed of light --- and getting mass to 1/3 the speed of light is absolutely impossible.

    Escape velocity from the Sun is 617 km/per second --- not even New Horizons at 35,000 kph is anywhere close to that!

    Jupiter's escape velocity? About 60 kps --- so if New Horizons was 8 or 9 times faster, would match that.

    But black holes --- are not especially dangerous to humans in any way that any other massive objects (gas giants included) aren't. For some reason, we teach kids and adults that blackholes are "evil" and suck up everything --- but blackholes are very helpful holding galaxies together and binding our galaxies together so that they are warm and stable for extremely long periods of time.

    Without blackholes, the universe may not be able to support life without the stability that blackholes give to galaxies.

    So quit dogging our friends, the blackholes, you insensitive jerks!
  • Re:Spaghetti (Score:4, Interesting)

    by pscottdv (676889) on Sunday October 27, 2013 @03:59PM (#45253401)

    A black hole would eventually stretch a person into spagetti, but not necessarily near the event horizon. For a small black hole the effect might be well outside the event horizon while for a supermassive black hole the effect would be well inside of it.

    This is because the event horizon of a super-massive black hole is so large that while the gravitational pull there is enormous, the variation in the graviational forces in a human-sized volume is quite small. It's the variation in the forces that stretches you.

    Likewise, while the total gravitation pull well outside the event horizon of a small black hole is much less than the total gravitational pull near the event horizon of a super-massive one, the variation is much higher.

  • by globaljustin (574257) <justinglobal.gmail@com> on Sunday October 27, 2013 @04:09PM (#45253487) Homepage Journal

    hey man...good thoughts...

    I think I might have some answers...

    It seems, and this research bolsters the idea, that the Event Horizon obliterates **everything** and scatters the energy across the event horizon. Anything like "Hawking Radiation" then becomes just another result of the Event Horizon obliterating matter. The characteristics (information) of the matter (speed, mass, velocity, spin, charge, etc etc) are truly completely obliterated at the Event Horizon.

    In this way, *nothing* ever actually crosses the Event Horizon. The 'Black Hole' then functions as a perfect 'black body'.

    This view has repurcussions across physics. If what I say is true, then essentially, Black Holes could be viewed as bubbles in the Quantum Foam of the universe. Which means the universe ends in heat death.

  • by maxwell demon (590494) on Sunday October 27, 2013 @06:15PM (#45254343) Journal

    Of course space isn't really black; rather it is completely transparent. It's the cosmic horizon behind it which is black. Actually at the horizon there's the glow of the big bang, but it is so heavily red-shifted that we only see it in the microwave range (the cosmic microwave background). Now in principle, when looking in the microwave range, black holes should be detectable as "microwave shadows". However I don't think we can measure microwaves in sufficient angular resolution for that.

  • by Anonymous Coward on Sunday October 27, 2013 @06:46PM (#45254465)

    No he wouldn't. With an acceleration of 1g you can reach the edge of the visible universe in a mere 40 years due to time dilation. A nearby black hole would take much less time.

    See http://math.ucr.edu/home/baez/physics/Relativity/SR/rocket.html

  • Re:Spaghetti (Score:4, Interesting)

    by WolfWithoutAClause (162946) on Sunday October 27, 2013 @11:34PM (#45256021) Homepage

    My understanding/way I imagine it is that; as you move towards the blackhole, the particles that make up the astronaut cause the event horizon to come out to meet them, and this curves the event horizon and this causes a local burst of Hawking-type radiation that rips apart the astronaut, and this radiation spreads out from the impact point in a wave; that in turn creates more perturbations of the horizon and so on. You end up with a very thin ring of fire all around the black hole. And this never goes away; indeed it forms the moment the black hole does, and so there's actually nothing inside the blackhole, just flat spacetime. In a sense I suppose the collapse never completely happens you end up with just a shell of matter.

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