What is a supernova?

A supernova is defined as a massive explosion that occurs at the end of a star's life cycle, making this the correct answer. This dramatic event marks the death throes of a star, typically one that is significantly larger than our Sun. During a supernova, the core of the star collapses under gravity, leading to a violent explosion that ejects the outer layers of the star into space at incredible speeds.

The energy released during a supernova is immense, often outshining entire galaxies for a brief period and contributing to the creation of heavy elements through nucleosynthesis. This process enriches the interstellar medium with elements that can later form new stars and planets, playing a crucial role in cosmic evolution.

Understanding supernovae is vital because they not only signal the end of a star’s life but also the birth of new material that becomes part of future stellar systems. This cycle illustrates the interconnectedness of stellar life and death in the universe.