Cassiopeia A

Cassiopeia A is a supernova remnant is in the constellation Cassiopeia. Scientists have found the remnants of a dead star which they believe was destroyed some 300 years ago in a massive supernova that apparently turned the left over stellar corpse inside out. As of now, Cassiopeia A is the brightest extrasolar radio source in the sky. The supernova occurred approximately 11,000 light-years away in the Milky Way.