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I How do things pass through event horizons?

  1. Jul 23, 2017 #1
    So, as a proton crosses the event horizon, wouldn't one of the quarks go in first before the others, which means the gluon connection between that quark and the others are severed( the quark on the inside is not casually connected with the in falling quark on the outside as gluons cannot be sent out of the event horizon to establish a connection)? If this is the case, then wouldn't all baryonic matter get dismantled on the way through, maybe in the form of quark gluon plasma? Or would they reconnect?
     
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  3. Jul 24, 2017 #2

    Nugatory

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    Before you start thinking about quarks and protons.... consider dropping two beads connected by a string into a black hole. Must the string break?
     
  4. Jul 24, 2017 #3

    PAllen

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    The event horizon, classically, is locally completely undetectable. For a supermassive BH, a body falling through the horizon would detect no difference whatsoever between outside the horizon, half in, and all in. This is actually built in to the fundamental structure of GR - locally everywhere and every when in spacetime is indistinguishable from SR in Minkowski spacetime.

    There are arguments that treated quantum mechanically, the horizon becomes a firewall, but this has nothing to do with your description. This argument is based on entanglement of states outside and inside.
     
  5. Jul 24, 2017 #4
    Depends on the tidal forces. But for large enough blackhole, there is no reason why it would break, as least classically. But quarks need to communicate via exchange gluons with other quarks to maintain the structure of the proton. If a quark falls in before the gluon and other quarks do, then how would that exchange gulon know where to go to? The event horizon prevents the inner quark from communicating with the outer quark. Thus they are no longer bound.
     
    Last edited: Jul 24, 2017
  6. Jul 24, 2017 #5

    Orodruin

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    How do you think a string works?

    As has already been said, there is nothing special about the event horizon. If you want to keep one quark outside after the others have fallen in you will need to give it a humongous acceleration, enough that the other quarks would be outside its Rindler horizon in the local description. This is what will break it. Not the fact that it is passing the event horizon.
     
  7. Jul 24, 2017 #6
    So the exchange gluon is like a string? I take that you are not discussing string theory. So the quark on the inside doesn't need to send a signal via an exchange gluon from the inside to the outside? Because the connection is like a string?
     
  8. Jul 24, 2017 #7
    Yea, I am excited to know that we can enter into event horizon of a supermassive black hole whose mass is million times of the sun's without lethal damage. we could bite not crushed FallenApples in our bags after passing through the event horizon. In the system of falling man there is no event horizon so atomic nucleus of our bodies or our apples undertakes no real torsion in any system, I assume.
     
    Last edited: Jul 24, 2017
  9. Jul 24, 2017 #8
    I don't know about that. A person that passes though the event horizon of a supermassive blackhole will have part of their brain go in first, well that part of the brain cannot communicate with the other part on the outside via electrical signals fired between neurons, which could lead to total brain shutdown. Theres also problems regarding bloodflow. Blood cannot flow from inside the event horizon to outside, meaning possible complete organ disruption once the person makes makes it through. Maybe if the person keeps moving forward, the bloodflow issue can be bypassed, assuming enough momentum. But I just can't see how they would prevent severe damage to the brain caused by sudden complete disconnection of the neuronal signals. Of course, this is all assuming the person doesn't turn into quark soup.
     
  10. Jul 24, 2017 #9
    Locally indistinguishable? What if I put the left side of my head into the event horizon first, while keeping the right side out? The two brain hemispheres cannot communicate with each other and I probably wouldn't be concious anymore by the time I have fallen in.
     
  11. Jul 24, 2017 #10
    Can you substantiate this assertion with explicit calculations? Or you just intuitively "don't see"?

    Probably? You understand that the part of the brain outside the horizon would quickly get sucked inside? You think, I suppose, that it may not be fast enough for it to catch up with the signal from the other part of the brain, before it starts to feel weird.
    Of course, if you keep (by grabbing it with something very strong and pulling it away from the horizon) the right side of the brain out, it would definitely be detectable. Locally, it would look like the right side of the brain would be forcefully torn away from the left.
     
  12. Jul 24, 2017 #11

    Orodruin

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    You do the same fallacy over and over again. If part of the brain goes in, the other part will follow unless there is extreme acceleration of the other part. It is the acceleration (or rather, difference in acceleration) that will destroy the brain. Not the fact that the brain passes the event horizon. Locally this is no different from a brain in Minkowski space.
     
  13. Jul 24, 2017 #12

    Orodruin

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    You seem to think of the event horizon as a two-dimensional surface in space. It is not. It is a light-like surface in space-time.
     
  14. Jul 24, 2017 #13
    Hi. Nothing can go into event horizon in finite time due to gravitational time dilation in the coordinate whose faraway region is inertial. Every thing stops in front of event horizon.
    Free fall person goes into event horizon of supermassive blackhole in his/her own coordinate with no damage or disconnection of brain.
     
  15. Jul 24, 2017 #14
    Yes, I think this is the source of the confusion. So the event horizon is not clear cut off in space then?
     
  16. Jul 24, 2017 #15

    Orodruin

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    Locally it is a surface moving at the speed of light for all observers. It has no rest frame.
     
  17. Jul 24, 2017 #16

    PAllen

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    This was already explained before. To keep part of you out you would need enormous accelearation of the part remaining out relative to the part falling in. This is what would break you, nothing to do with the horizon. If the body is in free fall, the local physics crossing this horizon is indistinguishable from inertial motion anywhere else. This feature is built into the structure of a pseudoriemannian manifold, and an exception cannot even be represented mathematically.
     
  18. Jul 24, 2017 #17

    Vanadium 50

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    Once.
     
  19. Jul 24, 2017 #18

    Ibix

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    An event horizon is a null surface. That means that - in the local inertial frame of an infalling observer - it passes through you at the speed of light. So if the left half of your brain is inside there are only two options. Either the right side of your brain ends up inside the event horizon before it could even theoretically be aware that the left side is trying to communicate with it. Or something messy happens and the two lobes of your brain part company permanently. The first case is locally undetectable. In the second case you are killed by whatever ripped your skull in half, not by the event horizon.
     
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