This story first appeared on Brookhaven’s website.
They come from the midst of exploding stars beyond our solar system — and possibly, from the nuclei of far distant galaxies. Their name, “galactic cosmic rays,” sounds like something from a science fiction movie. They’re not really rays.
Galactic cosmic rays (GCR) is the term used to describe a wide variety of charged particles traveling through space at high energies and almost the speed of light, from subatomic particles like electrons and positrons to the nuclei of every element on the periodic table. Since they’re created at energies sufficient to propel them on long journeys through space, GCRs are a form of ionizing radiation, or streaming particles and light waves with enough oomph to knock electrons out of their orbits, creating newly charged, unstable atoms in most of the matter they traverse. (more…)