Answer: Eris is a dwarf planet like Pluto. It has it's own moon, Dysnomia. Eris and Pluto are sometimes referred to as Kuiper Belt Objects. They are made of ice and rock. read more
Neptune orbits the Sun precisely three times for every two of Pluto's orbits, which means Pluto is a safe distance from Neptune. Charon formed by a giant impact similar to how our moon is thought to be formed. read more