Eris is the most massive and second-largest known dwarf planet in the Solar System. Eris was discovered in January 2005 by a Palomar Observatory-based team led by Mike Brown, and its discovery was verified later that year. In September 2006 it was named after the goddess of strife and discord.
Like almost all of the known dwarf planets (with the exception of Ceres), Eris lies in the Kuiper Belt, which rings the outer solar system. But Eris is even farther-flung than Pluto, circling our star about three times farther away.
The plane of Eris' orbit is well out of the plane of the solar system's planets and extends far beyond the Kuiper Belt, a zone of icy debris beyond the orbit of Neptune. As Eris orbits the Sun, it completes one rotation every 25.9 hours, making its day length similar to ours.
It takes 557 Earth years for Eris to make one orbit around the Sun. It has a highly eccentric orbit around the Sun, which causes its surface temperature to vary from -217 degrees Celsius to -243 degrees Celsius.
Though its gravity is weak compared to earth, Eris has the strongest gravity out of all the dwarf planets: 0.82 m/s².
Its mass is 0.27 percent of the Earth's mass and 27 percent more than dwarf planet Pluto's, though Pluto is slightly larger by volume. 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.