I’ve always been interested in astronomy, and at a young age I learned all about red giants, white dwarves, and black holes. I spent a lot of nights during the second semester of my freshman year in college at the telescope in the science center while I was taking a course called Astronomy 14.

Yesterday I went with my younger son to the Hayden Planetarium and saw their current show, Journey to the Stars. And I learned about a class of stars I’d never heard of before: the brown dwarf.

Actually, the brown dwarf isn’t really a star. It’s a sub-stellar body that isn’t massive enough to maintain nuclear fusion at its core. Brown dwarfs (yes, that’s the way the plural is spelled) are more massive than giant gas planets like Jupiter but less massive than the smallest stars. They usually have masses between 15 and 75 times the mass of Jupiter. The Planetarium show refers to the first confirmed brown dwarf, which was discovered in 1995 in the Pleiades star cluster.

Some astronomers think that the universe may be full of brown dwarfs and that they may provide the answer to the famous problem of the universe’s “missing mass.”

If you find all of this as fascinating as I do, you may enjoy the trailer for Journey to the Stars below.

And this page from CalTech’s Cool Cosmos website has some cool renditions of brown dwarfs.