Cosmic Identity Crisis Resolved

Pluto, formerly known as the ninth planet in our solar system, has officially been given a new label: plutoid. The International Astronomical Union (IAU) decided on the name yesterday, which distinguishes all dwarf planets located farther from the sun than Neptune.

Dwarf planets are not-quite-planets, massive enough to assume a near spherical shape from self-gravitational force, but not large enough to have their own orbital zone, or become gravitationally dominant like real planets.

The discovery of Eris in 2003 triggered the reclassification craze. Eris, a dwarf planet larger and farther from the sun than pluto, is currently the only other plutoid aside from pluto.

Astronomers examining Eris' characteristics became aware of certain discrepancies in bodies characterized as planets. The demotion of pluto to a nameless dwarf planet by the IAU Committee on Small Body Nomenclature followed shortly in 2006.