In the Universe, various environments are characterized by shocks capable of converting the kinetic energy of gas and particle flows into heat, turbulence, magnetic energy, and, ultimately, accelerating particles to relativistic energies, producing cosmic rays. The sizes of these systems can vary by many orders of magnitude, ranging from the typical dimensions of the interplanetary environment to the enormous galaxy
SN1987A, the supernova exploded in the Large Magellanic Cloud (at about 170000 light years of distance) on February 23rd 1987, was an iconic event for the study of supernovae and supernova remnants. In fact, it is the only case where it was possible to observe (with telescopes) the explosion and to follow with periodic observations the evolution of the supernova
