Eris is the most massive and second-largest dwarf planet in the known Solar System. Eris was discovered in January 2005 by a Palomar Observatory-based team led by Mike Brown, and its identity was verified later that year.
In September 2006 it was named after Eris, the Greek goddess of strife and discord. Eris is the ninth most massive object directly orbiting the Sun, and the 16th most massive overall, because seven moons are more massive than all known dwarf planets.
Eris is a trans-Neptunian object (TNO) and a member of a high-eccentricity population known as the scattered disk. It has one known moon, Dysnomia. (Eris and Dysnomia are seen in the first image).