Eris : Dwarf Planet

Eris is one of the largest known dwarf planets in our solar system. It's about the same size as Pluto, but is three times farther from the Sun.

Eris first appeared to be larger than Pluto. This triggered a debate in the scientific community that led to the International Astronomical Union's decision in 2006 to clarify the definition of a planet. Pluto, Eris and other similar objects are now classified as dwarf planets.

Originally designated 2003 UB313 (and nicknamed for the television warrior Xena by its discovery team), Eris is named for the ancient Greek goddess of discord and strife. The name fits since Eris remains at the center of a scientific debate about the definition of a planet.

Eris was discovered on Oct. 21, 2003 by M.E. Brown, C.A. Trujillo, and D. Rabinowitz at the Palomar Observatory.

Size and Distance
With a radius of about 722 miles (1,163 kilometers), Eris is about 1/5 the radius of Earth. Eris, like Pluto, is a little smaller than Earth's Moon. If the Earth were the size of a nickel, Eris would be about as big as a popcorn kernel.

From an average distance of 6,289,000,000 miles (10,125,000,000 kilometers), Eris is about 68 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes sunlight more than nine hours to travel from the Sun to the surface of Eris.