Eris

Eris (136199 or UB313) is the most massive known dwarf planet in the Solar System and the ninth most massive body known to orbit the Sun directly. Eris is the most distant object ever seen in orbit around the Sun, the Kuiper Belt object discovered in 2003. The object was discovered on January 5, 2005 by Mike Brown, Chad Trujillo and David Rabinowitz at Palomar observatory in the out reaches of the Kuiper belt.
Category:Dwarf planets