Despite its name, brown dwarfs aren't exactly brown neither are they that small either. They are celestial objects with features similar to stars and planets but not really belonging to either class. Rather they are an entity of their own.
It sounds like the start of a really bad riddle: "I'm bigger than a planet, but I'm not a star. And I'm smaller than a star, but I'm not a planet. Who am I?"
But instead of a cheesy brain-teaser, this is actually an entry point into exploring just how astronomers classify the exotic objects of our universe. It's also an opportunity to understand some of the weirdest citizens of the Milky Way.
The answer to the riddle, by the way, is "I'm a brown dwarf."
(Image credit: NASA/JPL-Caltech via Space)