University of Edinburgh

BSL Astronomy Glossary - supernova - definition

Definition: A supernova is caused when a supergiant star explodes. Supergiants are massive stars, considerably larger than the sun. As they burn, they eventually run out of fuel and die in a huge explosion. The explosion is so powerful that, for the short duration before it finally fades, a supernova can shine more brightly than all the stars in the galaxy put together.