Eris: The Largest Known Dwarf Planet

Explanation: Is Pluto the largest dwarf planet? No! Currently, the largest known dwarf planet is (136199) Eris , renamed last week from 2003 UB313 . Eris is just slightly larger than Pluto, but orbits as far as twice Pluto 's distance from the Sun. Eris is shown above in an image taken by a 10-meter Keck Telescope from Hawaii , USA . Like Pluto, Eris has a moon, which has been officially named by the International Astronomical Union as (136199) Eris I (Dysnomia). Dysnomia is visible above just to the right of Eris. Dwarf planets Pluto and Eris are trans-Neptunian objects that orbit in the Kuiper belt of objects past Neptune. Eris was discovered in 2003, and is likely composed of frozen water-ice and methane . Since Pluto's recent demotion by the IAU from planet to dwarf planet status, Pluto has recently also been given a new numeric designation: (134340) Pluto. Currently, the only other officially designated “dwarf planet” is (1) Ceres .