When looking up at the night sky, you might wonder how there are so many stars.

Astronomy is one of the earliest recorded sciences practiced. Prehistoric ancestors painted star constellations on cave walls, and early Greek astronomers were among the first to determine that Earth revolves around the sun. Today, scientists have learned much more about stars and their life cycles.

So, how do stars evolve? There are six stages of a star’s life, with two (technically three) possible paths that the star can live through. Stars begin as clouds of gas and debris called a stellar nebula, also known as a giant cloud of gas. The second stage occurs when this cloud of gas collapses under gravity, forming a protostar.

The third stage is T-Tauri, named after a star, found in the Tauras constellation. During this stage, the protostar undergoes gravitational collapse, causing matter to collapse in on itself. Next comes the main sequence, the stage in which a star spends most of its life in.

Eventually, the star expands into a red giant.  Smaller stars then become white dwarfs, while larger stars explode into a supernova, potentially forming a black hole or neutron star.