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Homework Help: How exactly does Hawking radiation work?

  1. Feb 16, 2017 #1
    1. The problem statement, all variables and given/known data
    For school I'm doing a project on hawking radiaton but I have very big difficulties trying to understand it.
    I'm trying to understand the matter about: Unruh effect, particle pair (antimatter - matter) and the theory of relativity regarding vaccuum.

    2. Relevant equations

    3. The attempt at a solution
    What I now think about hawking radiaton:
    Energy travels inside the gravitational pull of a black hole. Due to the Unruh effect, a particle pair will be created. I don't know how, but they get seperated and one of the two gets outside the gravitational pull in the form of radiation. The other will go inside the black hole, but because it is antimatter, the energy of the black hole will decrease, so in time the black hole will evaporate.
    What I think I know about the unruh effect:
    In a vaccuum cannot be any particles. But if a observer accelerates, particles will be observed in the stationary vaccuum.
    Because of the theory of relativity, the gravitational pull can be considered as acceleration so the unruh effect takes place at the black hole.

    I'm aware that many of this will probably be not right. I'd appreciate it very much if someone could say what is correct and if not correct, could complement it.
    Thanks in advance!
  2. jcsd
  3. Feb 16, 2017 #2


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    The whole "virtual particle" description of Hawking Radiation is NOT what actually happens. Hawking said that it was the best he could come up with to describe in English something that really can only be described in the math. You'll see it in pop-sci presentations, but not in physics textbooks.

    I have no idea what you might have in mind when you say "In a vaccuum cannot be any particles"
  4. Feb 16, 2017 #3
    Thanks for your answer!
    So is it known what really happens? I don't have access to physics textbooks and have to work with google.
    Further, I read somewhere ( can't find where) that in a vacuum, it is not possible to have any particles. Only energy can exist in a vacuum. So this is not true?
  5. Feb 16, 2017 #4


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    Staff: Mentor

  6. Feb 16, 2017 #5


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    It is known of course, but my understanding is that you have to understand some wicked complex math to understand it
    It is not only not true, it is nonsensical.
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