A supernova is one of the most powerful explosions in the universe: the catastrophic death of a massive star. When certain stars run out of fuel after millions or billions of years, they collapse inward and then explode outward with such tremendous force that for a few weeks, a single dying star can shine brighter than an entire galaxy of billions of stars.

During a supernova, the star blasts its outer layers into space at speeds of millions of miles per hour, creating spectacular clouds of gas and dust that can be seen from Earth even though they're unimaginably far away. The explosion is so energetic that it forges heavy elements like gold and iron, scattering them across space. Every atom of gold in your jewelry and every atom of iron in your blood was created inside a star and flung into space by a supernova billions of years ago.

Astronomers have observed supernovas throughout history. In 1054, Chinese astronomers recorded a “guest star” so bright it was visible during the day for weeks. That supernova created the Crab Nebula, a glowing cloud of debris still expanding today. Though supernovas are rare in any single galaxy (happening maybe once per century), scientists spot them regularly because they're watching millions of galaxies.