The Dwarf Planet Xena

Discovery

• On Oct. 31, 2003, Eris was first sighted by Mike brown, a scientist working at the California Institute of Technology, alongside astrologer Chad Trujillo. The pair used a 48-inch Samuel Oschin Telescope, funded by NASA, to spot the dwarf planet. It wasn't until 2005, however, that the scientists, working with astrologer David Rabinowitz of Yale University, noticed Eris' motion. The official announcement of the planet's existence was made on July 29, 2005.

Naming

• Eris' original name of Xena was given to the dwarf planet by Brown and his team of astrologers. The name was inspired by the fantasy TV series "Xena: The Warrior Princess," which was set in the land of mythical Greece and starred Lucy Lawless. In keeping with the theme, the dwarf planet's moon was named Gabrielle, just like Xena's companion in the series. In 2006, the dwarf planet was renamed Eris, a name inspired by the Greek goddess of discord. Eris was known for causing wars and disputes between men. The dwarf planet's moon was renamed Dysnomia; in the Greek pantheon, Dysmonia is Eris' daughter and represents lawlessness.

Controversy

• The International Astronomical Union (IAU) sets three criteria for an astrological body to be classed as a true planet, but as Eris doesn't clear its orbit, it is classified as only a dwarf planet. Eris is 27 percent bigger than Pluto however, which in 2005 was still a planet, prompting the IAU to reconsider how planets and dwarf planets should be defined. The IAU voted on this definition at a 2006 conference in Prague, and since Pluto cannot also clear its orbit, it was demoted to a dwarf planet. Eris was also held to be a dwarf planet, becoming the largest such body in the Solar System.

Distance

• Eris is the most distant astrological body that orbits the sun that scientists have discovered. It is roughly 97 astronomical units from the sun, with each such unit representing the distance between the Earth and the sun. Eris takes around 560 years to make an orbit around the sun, according to the Science Daily website, and its elliptical orbit means that sometimes Eris is only 38 astronomical units away from Earth, bringing it temporarily closer than Pluto.

Surface

• Eris' surface appears as yellow or reddish to observers. Although unconfirmed as of 2011, scientists think it likely that Eris' surface is made up of frozen methane, with a temperature of between -358.6 degree Fahrenheit and -405.4 degree Fahrenheit.