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Ultra high energy cosmic particles?

  1. Dec 21, 2004 #1
    ultra high energy cosmic particles??

    I know there have been serveral instances where protons have been detected travelling through our atmosphere with energies in excess of [tex]3*10^{20}[/tex] eV. This means that they might cause macroscopic effects as the proton would be travelling at speeds close to [tex]C[/tex]. Im just wondering if anyone can come up with a theory as to why and how this can happen??

    I dont think its been solved so feel free to include random new strange theories, i enjoy reading them! :rolleyes:

    Last edited: Dec 21, 2004
  2. jcsd
  3. Dec 21, 2004 #2
    One of the theories for the high velocities of cosmic rays is called Fermi acceleration. It postulates that cosmic rays are accelerated by magnetic fields
  4. Dec 22, 2004 #3


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    tozhan, do you have any references or sources which identify the method for detecting or discovering 3E20 ev (3E8 TeV) protons?

    Those energies are more than 3E11 times the rest energy (938.3 MeV), so the velocities would certainly approaching the speed of light.
  5. Dec 23, 2004 #4


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    While not a direct answer to your question Astronuc, this paper ("Cosmic Physics: The High Energy Frontier", F.W. Stecker) is one of my favourites as an overview of the field. It contains plenty of references ... I think you'll find that the most energetic CR was detected by the Japanese AGASA experiment, and that 'Fly Eye' detectors have also been used. Basically, the method(s) involve detection and analysis of air showers.
  6. Dec 23, 2004 #5


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  7. Dec 23, 2004 #6
    Cosmic Rays in general are believed to be created from supernova explosions in our galaxy and possibly from other galaxies. Protons are ejected from the explosion at extremely high velocities, although this doesnt completely explain where the extremely high energy comsmic rays (10^20 eV) come from. There is only speculation about where these extreme high energy CR come from, if i recall correctly, one possibily is because of a special type of supernova, one so violent that it causes the creation of a black hole. Another possibility is from the acceleration of protons because the the enourmus magnetic fields caused by spinning black holes and very fast spiraling ionized gas falling into the black hole.
    This past summer I went to Brookhaven National Laboratory to study cosmic rays and build detectors for them. The design of the detectors were pretty simple, made of mainly dopped lucite and a Photo-Multiplier tube. When a cosmic ray enters our atmosphere traveling at very high speed, it travels a down a great deal until it reaches relativly dense air, and then collides with an air molecule. The collision causes a series of events leading to a shower of particles. The collision between a proton and an air molecule would produce mainly pion, which are composed of a pair of quarks. There would be positive pions (antipions), negative pions, and neutral pions. A positive pion would decay into a positive muon (antimuon), and then into a positron along with certain flavors of neutrinos. A negative pion would decay into a muon, and then into an electron along with other flavors of neutrinos. The neutral pion is a quark/antiquark pair, and therefore decays almost instantly into two xray/gamarays going in opposite directions in order to conserve momentum. The photons will then interact with heavy nucleii in the atmosphere and convert into an electron/positron pair. Once a particle from this shower goes through the lucite in the detector, it will emitt Cherenkov radiation, which will be detected by the PM tube and converted into an electrical signal that can then be analysed.

    ps. sorry for my terrible spelling
    Last edited: Dec 23, 2004
  8. Jun 18, 2010 #7
    Re: ultra high energy cosmic particles??

    I was reading that some of these ultra high energy cosmic rays had the amount of kinetic energy as a small golf ball moving @ 90km/h+?

    Would you feel or get injured if getting hit by one of these cosmic rays at that energy?
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