Paul M. Sutter is an astrophysicist at SUNY Stony Brook and the Flatiron Institute, host of Ask a Spaceman and Space Radio, and author of How to Die in Space. He contributed this article to’s Expert Voices: Opinions and Insights.

It’s easy enough to say what a star is. It’s one of those bright pointy things that twinkle in the night sky. But beyond that, the actual definition of a star is as rich and colorful as, well, the stars themselves.