A supernova is the catastrophic explosion of a star. It can outshine an entire galaxy for weeks and release more energy in that time than the Sun will emit in its entire lifetime. Supernovae forge heavy elements, trigger star formation, and leave behind neutron stars or black holes. They are both destructive and creative.

There are two main types. A Type Ia supernova occurs in a binary system when a white dwarf steals matter from a companion star, grows too massive, and explodes. These supernovae have a consistent peak brightness, which makes them standard candles for measuring cosmic distances. A core-collapse supernova occurs when a massive star exhausts its nuclear fuel and its iron core collapses. The rebound sends a shock wave through the star, blowing it apart.

Supernovae are rare in any given galaxy. The Milky Way has not had a visible one since 1604, when Kepler's Star appeared. But they are common across the universe. Astronomers discover hundreds every year.

The elements in your body were forged in supernovae and red giants. Without them, the universe would be hydrogen and helium. Supernovae are how the cosmos makes the stuff of life.