Space.com:

Astronomers have discovered a potential "rogue" alien planet wandering alone just 100 light-years from Earth, suggesting that such starless worlds may be extremely common across the galaxy.

The free-floating object, called CFBDSIR2149, is likely a gas giant planet four to seven times more massive than Jupiter, scientists say in a new study unveiled today (Nov. 14). The planet cruises unbound through space relatively close to Earth (in astronomical terms; the Milky Way galaxy is 100,000 light-years wide), perhaps after being booted from its own solar system.

In the movie Melancolia, earth is destroyed by a rogue planet.