Supernova Shock Wave (image) DOE/SLAC National Accelerator Laboratory Caption When stars explode, the supernovas send off shock waves, which accelerate protons to cosmic-ray energies through a process known as Fermi acceleration. In this mechanism, named for Enrico Fermi who first hypothesized it, the protons gain energy from collisions with turbulent magnetic fields on either side of a shock wave. Though many details of Fermi acceleration remain unknown, new results from the Fermi Gamma-ray Space Telescope provide overwhelming evidence that the mechanism is indeed responsible for producing many of the galaxy's cosmic ray protons. Credit Greg Stewart, SLAC National Accelerator Laboratory Usage Restrictions Please provide credit Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.