Eris

Eris, is the most massive known in the Solar System and the ninth most massive body known to orbit the Sun directly. It is estimated to be approximately 2300–2400 km in diameter. Eris, was spotted in January 2005 (first seen in 2003, however important factors were confirmed in 2005) by Michael Brown. Eris takes approximately 550 earth years to orbit the sun.  The majority of the time, it is further from the sun than Pluto, but for a short time, it is closer. Eris is actually larger than Pluto (it is the ninth largest object orbitting our sun discovered so far!). Eris is named after the Greek goddess Eris, a personification of strife and discord.