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Thread: Is antimatter massless?

  1. #1

    Is antimatter massless?

    Is antimatter massless? Does it have negative mass?

  2. #2
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    It has mass and I believe it has positive mass (I'm not sure what negative mess could be).
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  3. #3
    OK ... so here is the follow up ...

    Wouldnt Hawking radiation actually increase the mass of a black hole?

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    Quote Originally Posted by tommac View Post
    OK ... so here is the follow up ...

    Wouldnt Hawking radiation actually increase the mass of a black hole?
    No.

    One of the virtual paraticles falls into the black hole whilst the other escapes (becoming a real particle). In order to preserve total energy , the particle that fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process, the black hole loses mass,

  5. #5
    Quote Originally Posted by gzhpcu View Post
    No.

    One of the virtual paraticles falls into the black hole whilst the other escapes (becoming a real particle). In order to preserve total energy , the particle that fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process, the black hole loses mass,
    preserve total energy? wouldnt that happen regardless which particle fell in?

  6. #6
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    Tom,

    You have forgotten how Hawking radiation does its thing. I forgot that
    sometimes after first learning about it, myself, confusing ordinary matter
    versus antimatter with virtual matter versus physical matter. Now that
    I've gone through the explanation a half-dozen times or so, I think it may
    stick in my head.

    Everywhere, pairs of virtual particles pop into a kind of ghostly existence
    and then come back together and pop out of existence again before their
    existence can be directly detected. Near the event horizon of a black
    hole, usually both virtual particles either fall in or escape, but fairly often
    one will fall in while the other will escape. The fact that the two virtual
    particles are then unable to come back together and go out of existence
    promotes both particles to physical particles. The energy required to
    change the virtual particles into physical particles comes from the black
    hole's gravity: it is the steep gravity gradient of the black hole that pulls
    the particles in opposite directions and causes them to be separated.
    The particle that escapes carries away half the energy of the pair. The
    particle that falls in has the other half of the energy of the pair. So when
    a pair of virtual particles becomes physical, half the energy given to those
    two particles by the black hole's gravity escapes. A net loss of energy
    by the black hole.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  7. #7
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    Tommac, do you really want to run a Hawking radiation discussion on three separate threads?

    Grant Hutchison

  8. #8
    Quote Originally Posted by grant hutchison View Post
    Tommac, do you really want to run a Hawking radiation discussion on three separate threads?

    Grant Hutchison

    I appologize ... Lets discuss it over at the other thread. Please close this one. When opening I didnt think taht they would end up in the exact same place.

  9. #9
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    Quote Originally Posted by tommac View Post
    preserve total energy? wouldnt that happen regardless which particle fell in?
    Yes. It can be either the particle or the antiparticle which falls in. Normally, they would annihilate each other. Since the particle which escapes becomes a real particle or antiparticle and has a positive energy, the particle or antiparticle falling in the black hole must have a negative energy (bookkeeping), which means that the black holes loses energy (mass).

  10. #10
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    Closed by request of the OP
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