What Is a Supernova?
Some stars behave as if it's better to burn out than to fade away. These stars end their evolutions in massive cosmic explosions known as supernovae.
When supernovae explode they jettison matter into space at some 9,000 to 25,000 miles (15,000 to 40,000 kilometers) per second. These blasts produce much of the material in the universeï¿½including some elements, like iron, which make up our planet and even ourselves. Heavy elements are only produced in supernovae, so all of us carry the remnants of these distant explosions within our own bodies.
Supernovae add enriching elements to space clouds of dust and gas, further interstellar diversity, and produce a shock wave that compresses clouds of gas to aid new star formation.
But only a select few stars become supernovae. Many stars cool in later life to end their days as white dwarfs and, later, black dwarfs.
A supernova can light the sky up for weeks, and the massive transfer of matter and energy leaves behind a very...