Scientists have known about these ridiculously energetic and high-velocity particles for nearly a hundred years. In daily life, cosmic rays may be familiar as the source of extra radiation airline passengers are exposed to. However scientists have been uncertain about where cosmic rays come from. The extreme conditions of temperature and speed that accompany supernovae and their remains made them a natural starting point for guesses. Now two separate Science papers finally provide evidence that cosmic rays do indeed come from supernovae remnants.