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Light escaping Black Holes

  1. Feb 26, 2010 #1
    So I'm watching this video:

    So it says that nothing, even light, can escape a black hole, "except for certain Quantum Mechanic situations" or something like that.

    What are these Quantum Mechanic situations they are talking about?

    Try to conceptualize this without math if possible, cause i won't remember the math description very well.

    I see this is a Quantum Physics page, i hope you can answer it.
  2. jcsd
  3. Feb 27, 2010 #2


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  4. Feb 27, 2010 #3
  5. Mar 8, 2010 #4
    There are two things if I remember right, one is Hawking Radiation, the other is what's called 'tunneling'. When it comes to Hawking radiation then that takes place at the EV (Event Horizon) which is the last place you can exist on, being said to still belong to this Universe. From passing there all light will 'disappear' never being able to 'climb out' of a BH.

    When it comes to how it does it, it's called 'virtual pair production'. as I understands it. One of the particles at the EV takes a path into our universe, the other get 'annihilated' inside the EV and 'virtual' means that the process normally takes place under Planck time and therefore isn't observable, as I understands it. When people speaks about BH 'communicating' through Hawking radiation they usually mean that the particle inside The EV is a negative one, possibly also creating photons in its annihilation with the still positive matter inside it.

    Another view is that as they 'transform' from virtual to 'real' particles they draw on the energy of the Black Hole as it is in that gravitational 'field' they are created therefore 'stealing' some of the BH 'mass'.

    When it comes to tunneling it's a totally different process. Normally when defining how tunneling works you speak about a' wavepacket' which, as I understands it, is a arbitrary defined 'collection' of sin waves representing a 'photon' with a arbitrarily defined 'cut out'. As the wavepacket reaches further than the gap/obstacle hindering a 'particle photon ' to pass, it is thought that it 'tunnel' that way, mostly due to Heisenberg's uncertainty principle which makes its 'position' undecided. What it 'in reality' seems to do is to take itself in the 'tail' and sort of 'compress' itself past that obstacle, or if you like 'jump/materialize' itself FTL loosely speaking :) Nota bene, some say that it takes a certain 'time' for it to do so too?

    Now, some call those both processes described the same when it comes to Hawking radiation?
    Others see them as different?

    As for myself, I haven't had the opportunity to observe neither one, as yet :)
    And Hawking radiation isn't proved, other than as a mathematical concept.

    So I'll wait and see. All of this is how i understands it though.
    And there might be so much more to it :)
    Last edited: Mar 8, 2010
  6. Mar 8, 2010 #5
    well, thanks.
    and FYI, it is proper English to say "As I understand It", but that is a math forum, not an English one so i'll let it slide.. lol.
  7. Mar 8, 2010 #6
    You're welcome.

    Checking your statement I found both used?
    So? maybe American vocabulary versus English?

    Thanks for the tip anyway:)
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