A star that died 340,000 years ago has provided fresh evidence that the energetic particles known as cosmic rays are being fired out by supernovae.
It is seems likely that a supernova’s shock wave can boost protons to the sort of huge energies found in cosmic rays. Direct evidence for this is hard to find, however, as cosmic rays are deflected by magnetic fields and so cannot be easily traced back to their source.
Now Italian researchers Marco Salvati of Arcetri Astrophysical Observatory in Florence and Bruno Sacco of the National Institute for Astrophysics in Palermo suggest that an…
