Introduction

Chinese astronomers studying the skies almost 2000 years ago suddenly noticed a brand new star—it shone brightly in the sky for about eight months before disappearing. This was the first recorded appearance of a supernova, and since then there have been fewer than ten that have been bright enough to be seen by eye.

To observers on Earth, supernovae may appear to be bright new stars (“nova” means “new” in Latin), but in fact, they are the explosion that marks the end stages of some stars, releasing tremendous amounts of energy. The light from a supernova is so bright that for a short time (days to months) it can outshine the combined light from all the other stars in a galaxy. The blast of energy from a supernova would destroy all life on any planet within a 50-light-year radius. 

Although supernovae are massively destructive, they are also responsible for the creation of elements heavier than iron, which is critical for life. Supernova explosions enrich the region of space surrounding them with matter like the oxygen you breathe and the calcium in your bones. The shock waves produced by their explosions can even trigger the formation of new stars and planetary systems.

Rubin Observatory will discover about one million supernovae per year. About ten thousand of these discoveries are a special type of supernova that can be used to measure the distances to galaxies in the Universe.