Nova vs. Supernova — What's the Difference?

A nova occurs in a binary star system where a white dwarf pulls material from its companion star, leading to a thermonuclear explosion on the white dwarf's surface. This results in a sudden brightening of the star. In contrast, a supernova is a catastrophic explosion marking the end of a massive star's life cycle, either due to the collapse of its core or a runaway nuclear fusion reaction, resulting in an incredibly bright and powerful burst of energy.

While novae are less intense and can recur in the same star system as the white dwarf continues to accrete material, supernovae are vastly more powerful and signify the star's final evolutionary stages, often resulting in the creation of a neutron star, black hole, or dispersing the star's material into space.

The brightness of a nova is significant but pales in comparison to a supernova, which can outshine entire galaxies and be visible from great distances across the universe. Supernovae also play a crucial role in distributing heavy elements throughout the cosmos, contributing to the chemical diversity necessary for planets and life.

Novae primarily involve hydrogen fusion on the surface of a white dwarf, whereas supernovae involve more complex nuclear reactions and can result in the fusion of elements up to iron in the case of massive stars or the synthesis of even heavier elements during the explosion.

The frequency of novae and supernovae also differs, with novae occurring more commonly within our galaxy due to their less catastrophic nature. Supernovae are rarer events, but their impact on the cosmos, including galactic evolution and chemical enrichment, is profound.