cosmic rays Hear it!

cosmic rays definition

☆ cosmic rays

streams of high-energy charged particles from outer space, composed of protons, alpha particles, and a few heavier nuclei, which bombard the atoms in the upper atmosphere and produce various secondary nuclear particles which shower the earth

Webster's New World College Dictionary Copyright © 2009 by Wiley Publishing, Inc., Cleveland, Ohio.
Used by arrangement with John Wiley & Sons, Inc.

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