Daily Mail 
September 22, 2017
For half a century, astronomers have been unable to find the source of the most energetic rays in our universe.
But now, after detecting them for more than a decade, South American researchers say cosmic rays come from outside the Milky Way.
The rays, consisting of energetic sub-atomic particles, may be born from violent events millions of light years outside our galaxy, evidence suggests,
The discovery reported in the journal Science follows 12 years of data collection by the Pierre Auger Observatory in Argentina.
The observatory has 1,600 particle detectors spread in a hexagonal grid over 1,160 square miles to detect cosmic rays,
Cosmic rays are tiny fragments of atoms, and they fill space with varying amounts of energies.
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