A rogue planet is a planet that’s not in orbit around any star. It’s by itself, in orbit around the galactic center. It may have formed around a star and perhaps some severe gravitational perturbation ejected it into the space between stars. In any case, only a few are known. In this discovery, a very large one was detected via its radio emissions. Fascinating.
Check It Out: Astronomers Have Discovered a Massive Rogue Planet