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B What does a black hole look like from the inside?

  1. Aug 25, 2016 #1
    According to this video, , if a black hole is large enough you could actually travel for some time within the event horizon without dying because the event horizon is so far from the actual singularity. So, assuming that's true, what would you see while you were inside the black hole?

    Here's what i think: if you launch a rocket on earth that can't reach escape velocity, at certain point it'll just come straight back down. Would it be the same for light? Light cannot reach escape velocity so would it just come straight back down at a certain point? If that's the case, wouldn't that make a sort of mirror like surface? The light goes up and comes back down as if reflecting off a mirror?

    And then on top of that, just because light can't escape it doesn't mean light can't enter. So would it be a reflective surface as well as a one way see through window to the rest of the universe?

    And one last thing, is it at all possible that light that enters the black hole could somehow enter an orbit around the singularity?

    I know I probably got a lot of this wrong, so I thank you for your patience and any help would be greatly appreciated!
     
    Last edited: Aug 25, 2016
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  3. Aug 25, 2016 #2

    Orodruin

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    The first thing you need to realise is that the black hole is very different from your classical gravity picture. In a black hole, space and time have very different meanings from those you would find in the weak gravitational field of a planet or even a regular star. The singularity is not a position in space, rather it is in the future of all observers.

    It is really not a question of escape velocity, again the classical view of weak gravitational fields comes back to haunt you. The light would never reach values of the radial coordinate which are larger than where it started. All events in the future light cone for any given event inside the black hole has a smaller radial coordinate. Note that the radial coordinate inside the black hole does not represent a distance, but rather a time. There really is no concept of "towards the centre" inside the black hole.

    No.

    No. The circular orbits of light around a black hole occur at values of r which are 1.5 times the Schwarzschild radius.
     
  4. Aug 25, 2016 #3
    It's possible in the sense that there might be a chocolate teapot orbiting Mars.
    The singularity in a black hole is not a physical object.
    The singularity word means that conditions at the center of a black hole cannot be described by our best theories.
    (Or in other words, nobody knows what is going on there)
    We do know though, that matter made of atoms, the familiar stuff of the world which we live in and can observe, that can't exist.
     
    Last edited: Aug 25, 2016
  5. Aug 25, 2016 #4

    1oldman2

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    Thanks for that perspective, I've never heard it put that way.
     
  6. Aug 25, 2016 #5
    Okay! thank you so much for the info sir. It's greatly appreciated. Looks like I need to firm up my understanding of what a black hole even is :)

    Thanks again!
     
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