A supernova is a brilliant cosmic explosion marking the violent death of a star. These explosions are extremely bright, and in its final blaze of glory, the death of a single star can outshine the combined light from the billions of other stars in its home galaxy. One recent supernova, named SN 2006gy, surprised astronomers because it was intrinsically much brighter than any previous explosion, and it lasted much longer as well. The tremendous amount of total energy released in the visual light of the explosion exceeded other supernovae by a factor of 100 or more, and traditional explanations of supernova power sources seem inadequate. (Astronomers use a simple naming scheme for supernovae, with SN and the year of explosion. The year is followed by a letter or two in order of discovery, starting with A through Z, then aa, ab, ac, …, ba, bb, bc, and so on.)