Supernova explosions of massive stars are common in spiral galaxies like the Milky Way, where new stars are forming all the
time. They are almost never seen in elliptical galaxies where star formation has nearly ceased. As a result, astronomers
were surprised to find a young-looking supernova in an old galaxy. Supernova PS1-12sk, discovered with the Pan-STARRS
telescope on Haleakala, is rare in more ways than one.