Ultrahigh energy cosmic rays are the highest-energy particles in the Universe, whose energies are more than a million times what can be achieved by humans. Professor Farrar proposes that binary neutron star mergers are the source of all or most ultrahigh energy cosmic rays; this scenario can account for the heretofore inexplicable narrow rigidity range of ultrahigh energy cosmic rays because the jets of binary neutron star mergers are generated by...
