Describe the phenomenon of supernovae.
A supernova is a powerful and luminous explosion that occurs when a star reaches the end of its life cycle. There are two main types of supernovae: Type Ia, which occurs in binary systems when a white dwarf star accumulates too much matter from its companion star, and Type II, which results from the collapse of a massive star's core. Supernovae are important for the distribution of elements throughout the universe and can briefly outshine entire galaxies.