For the first time, astrophysicists have confirmed that cosmic rays with ultra-high energies come from outside our Milky Way Galaxy. At the Pierre Auger Observatory in Argentina, cosmic rays have been detected from far off galaxies. Image credit: A. Chantelauze / S. Staffi / L. Bret / Pierre Auger Observatory. Cosmic rays are atomic nuclei arriving from outer space that can reach the highest energies (exa-electronvolt) observed in nature. Low-energy...
