Almost two years ago, a meeting of the International Astronomical Union (IAU) in Prague changed how scientists define a planet. In doing so, the astronomers present kicked Pluto out of the brotherhood of planets, relegating it to dwarf planet status. The simple change meant that the solar system now consisted of eight planets and four dwarf planets. The demotion of Pluto seems to have been one of the most popular stories that Nobel Intent has covered.

Since "transneptunian dwarf planet" does not roll easily off the tongue, IAU members promised to come up with a more vernacular-friendly word. In keeping their promise, at a recent meeting in Oslo, Norway, members of the IAU have approved a new name for such dwarf planets: plutoids.





Plutoids Pluto (left) and Eris (right)

Officially, a plutoid is a celestial body that orbits the Sun at a distance greater than Neptune, is massive enough for its gravity to have achieved a hydrostatic equilibrium, but not so massive that it has cleared the neighborhood around its orbit. Currently, there are two known plutoids, Pluto and Eris. As it stands, Ceres remains only a dwarf planet; it exists too close to the sun to be a plutoid. It is also believed that Ceres is a unique object, and most likely will not be given its own classification.

* Image Credit: IAU, NASA/ESA Hubble Space Telescope, H. Weaver (JHU/APL), A. Stern (SwRI), the HST Pluto Companion Search Team and M. Brown.