Evidence of cosmic-ray acceleration from a nearby supernova remnant

Cosmic rays seen at Earth show a wide range of particle energies, from 107 electron-volts (eV) to more than 1020 eV, the latter being about the same as the kinetic energy of a 450 gram football (soccer ball) being kicked across the pitch at about 8 meters per second. A plot of cosmic ray energies from the Milky Way galaxy often shows a fair amount of what scientists might call "structure"-interesting deviations from the underlying trend called "knees" and "ankles" that in...