A supernova is an astronomical event that occurs during the last evolutionary stages of a massive star’s life, whose dramatic and catastrophic destruction is marked by one final titanic explosion. This explosion is so powerful that it outshines an entire galaxy for weeks or months, before fading from view over the course of several years.
Supernovae are extremely important events in the cosmos. Not only do they signal the death of a star and the recycling of its material back into the interstellar medium, but they also release vast amounts of energy that can help to trigger new star formation. Additionally, supernovae are responsible for creating many of the heavy elements found in nature, such as iron and uranium.
There are two main types of supernovae: Type I and Type II. Type I supernovae occur in binary star systems when a white dwarf accretes matter from its companion star until it reaches a critical mass and ignites in a thermonuclear runaway reaction. Type II supernovae, on the other hand, occur when the core of a massive star collapses under its own weight, triggering an explosive outward blast wave.
It is thought that our own Sun will end its life as a Type Ia supernova sometime within the next few billion years. When this happens, it will likely be visible from Earth as a bright “new” star in the night sky for several weeks or months before slowly fading away over time.