Supernovae

A supernova is an extremely powerful stellar explosion — the violent end of a massive star's life (core collapse supernova, Type II) or the explosion of a white dwarf that accumulates too much mass from a binary companion (Type Ia). Supernovae briefly outshine entire galaxies — a single supernova can emit more light than 10 billion suns for a few weeks. They are the source of all elements heavier than iron (gold, silver, uranium, zinc, iodine) in the universe. Type Ia supernovae have a consistent luminosity (standard candles) — which astronomers use to measure cosmic distances. It was through Type Ia supernovae observations that Saul Perlmutter, Brian Schmidt, and Adam Riess discovered the accelerating expansion of the universe (dark energy) in 1998 — a discovery awarded the 2011 Nobel Prize in Physics. Supernova remnants (the expanding gas shells from explosions) are spectacular nebulae visible in telescopes — including the Crab Nebula (from a 1054 CE supernova recorded by Chinese astronomers).