Although the names appear similar, novae and supernovae actually represent vastly different physical phenomena from result from quite different physical processes. A nova results from the explosion of a white dwarf star. The explosion results from the increased mass of the white dwarf caused by matter falling onto its surface from a binary companion (usually a red giant star). Novae stars greatly increase from tens to hundreds of thousands of times in brightness (luminosity) before slowly fading back to normal luminosity. A supernova is a much more energetic event that in the course of stellar evolution marks the cataclysmic end of star's normal hydrogen fusion burning lifetime. Supernova explosions are among the most energetic events of the universe and a supernova may produce more luminosity that all of the other stars on the supernova's galaxy combined.

Stellar observations have provided ample evidence that some...