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Cosmic rays and the EM Spectrum

  1. Sep 7, 2004 #1
    In the 1969 edition of the World Book Encylopedia it shows that cosmic rays are considered part of the electromagnetic spectrum. In later editions the diagram doesn't show cosmic rays is part of the electromagnetic spectrum. In Capras famous book "The Tao of Physics, he also shows that cosmic rays are part of the EM-S. In other articles it states that cosmic rays were found to be atomic nuclei (in 1928) traveling close to the speed of light. I looked in a highly technical astronomy books and from what little I could decipher from the techno garble that cosmic rays fall into a gray area as far as whether they are radiation or particles. Richard Feynman once included cosmic rays as part of the EM-S in a video tape I saw of him. What gives? Are cosmic rays particles or radiation or possible both?
    Thanks, RAD
  2. jcsd
  3. Sep 7, 2004 #2


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    Both. Cosmic rays - particles - are protons and nuclei (e.g. He4); also electrons and positrons ... the term is usually shorthand for 'galactic cosmic rays', not 'solar cosmic rays'. Despite the former's name, some CRs clearly come from well beyond the Milky Way.

    High energy gammas are also 'cosmic rays', though they can be distinguished from particles by various techniques, hence VHE cosmic ray (gamma) 'telescopes' such as CANGAROO, HESSI, VERITAS. This site gives a brief overview of the particle CRs; http://www.physics.adelaide.edu.au/astrophysics/cr_new.html [Broken] is a brief summary of UHEs; CANGAROO
    Last edited by a moderator: May 1, 2017
  4. Sep 7, 2004 #3
    To: Nereid

    Thank you for taking the time and care in answering my question. Now I know why I was confused about this. RAD:)
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