Eris: Dwarf Planet King - Eris, the heavyweight champ of dwarf planets, holds the title of the most massive one in our solar system, despite being slightly smaller than Pluto. It's a frosty world residing way out past Neptune, in a chaotic region called the scattered disk. Eris travels on a long, oval-shaped path around the Sun, taking over 550 Earth years to complete one orbit. This mysterious world even has its own moon, Dysnomia, keeping it company in the deep freeze. | The Brain Maze