Cosmic rays: 50 year-old mystery has been solved


Ever since the existence of cosmic rays with individual energies of several Joules was established in the 1960s, speculation has raged as to whether cosmic particles of mean energy of 2 Joules are created in our Milky Way or in distant extragalactic objects.

In a paper that was published in Science on 22 September 2017, the Pierre Auger Collaboration reports observational evidence demonstrating that cosmic rays with energies a million times greater than that of the protons accelerated in the Large Hadron Collider come from much further away than from our own Galaxy.


Related paper:
Observation of a Large-scale Anisotropy in the Arrival Directions of Cosmic Rays above 8×1018eV

The Pierre Auger Collaboration, Science 357 (2017)
[doi: 10.1126/science.aan4338] [arXiv: 1709.07321]


The long Journey of Cosmic Rays

Video by Aurelio Grillo, Pierre Auger Collaboration, and Vincenzo Napolano, INFN Communication Office. 
Courtesy of Italian Institute for Nuclear Physics – INFN



The Pierre Auger Observatory



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