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Why Doesn't the Universe Explode Because of an Antimatter Reaction?

  1. Apr 14, 2012 #1
    So, semi-simple antimatter physics state that when antimatter comes in contact with regular matter, an explosion occurs. If there is only antimatter and matter in the universe, how can antimatter even exist, since it will come in contact with matter at one point and explode? So how are scientists able to capture it? They store it in a container made out if matter, so why doesn't that explode?

    This really doesn't make sense to me. Maybe there could be such a thing called neutral matter, whose atoms are solely composed of neutrons?
     
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  3. Apr 14, 2012 #2

    DaveC426913

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    And so it does. But space is big. And nearly empty.

    The "explosion" is really annihilation, with release of gamma radiation. We see lots of radiation in the universe.

    They store it in a magnetic bottle. The antimatter is prevented from contacting the container via magnetic fields.
     
  4. Apr 14, 2012 #3
    Hmm... But magnetism is created by charges the matter produces, and you don't need physical contact for the reaction to occur.
     
  5. Apr 14, 2012 #4

    phinds

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    If you mean the reaction that results in annihilation, then yes, you DO need physical contact.
     
  6. Apr 14, 2012 #5

    DaveC426913

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    Magnetism is particle-agnostic, just like photons. Yes, you do need physical collision for particles and anti-articles to annihilate.
     
  7. Apr 14, 2012 #6
    Oh, okay, thank you. I'm not be a physicist, (heck, I'm only a freshman in high school), so sometimes I get my facts screwed up.
     
  8. Apr 17, 2012 #7
    I don't think Anti-matter can be captured. Of course, I strongly contradict myself. But, there is some kind of belief in my self, may be a superstition, that anti-matter can't be captured or held in control with us.

    I support this by saying that energy is produced during collision of particles at particle accelerators. Collision means, we are colliding particles with other particles - not anti-particles. When such thing is done energy is produced. Energy is released when a particle and anti-particle combination takes place. Then how come anti-matter is produced all of a sudden, when matter is collided. We know, matter is formed only when matter and anti-matter combination already occurred and matter is more than anti-matter during those collisions.
     
  9. Apr 17, 2012 #8

    phinds

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    You should read some real science instead of just making things up in your head.

    Antimatter has been created and captured numerous times, although it has never been held for more than about 15 minutes so far.
     
  10. Apr 18, 2012 #9

    Vanadium 50

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    Antiprotons can stay in storage rings for days, no problem.
     
  11. Apr 18, 2012 #10
    i have been wondering this as well . I read somewhere that they have inveted a treatment against alzheimer that implys the use of a radiactive fluorine that emitts positrons and that are send into the brain so that they can attach to the affected areas , or somehting like that , and i wonder how this can be possible ? or have i understand this wrong ?
     
  12. Apr 18, 2012 #11

    Ryan_m_b

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    I think you are thinking of radioactive tracers or perhaps treatments where radioactive particles are targetted to specific locations. Nuclear medicine does deal with antiparticles, a good example is a PET scanner that measures the gamma rays released by a radioactive tracer.
     
  13. Apr 18, 2012 #12
    how come this PET doesnt explode the brain , it says that it emittes positrons , how come this positrons does not annihilate with the brains matter ? i understand how antimatter can be stored in magnetic fields , but how can this aplly in the brain when nuclear medicine uses antiparticle emittion inside the brain ?
     
  14. Apr 18, 2012 #13

    Ryan_m_b

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    Annihilation is what a PET scanner measures. Essentially a radioactive tracer is injected into the patient, this tracer is designed so that after a while it undergoes positive beta decay in which a proton is converted to a neutron realising a neutrino and positron in the process. The positron lasts very small fractions of a second before interacting with an electron in the brain, this causes the release of gamma rays that are then detected by the PET machinery. The reason the brain is not damaged is due to the fantastically small amounts of annihilation. In total a patient is exposed to less than 10 millisieverts of radiation.
     
  15. Apr 18, 2012 #14

    mfb

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    They quickly annihilate with electrons in the brain and emit gamma rays - that is they way these tracers work, the gamma rays get detected and tell the doctors something about the distribution of the tracer in the human. The energy released per volume is extremely low, so you don't get macroscopic effects like heat ("explosion").

    Edit: Too slow
     
  16. Apr 19, 2012 #15
    and they are so "slow " so they dont produce enough energy to create other antiparticle particle pairs , now i get it , thank you
     
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