Dwarf Planet

A body in our solar system that is larger than a comet or asteroid but not large enough to qualify as a major planet. This category was created by the International Astronomical Union in 2006. A dwarf planet is large enough that its gravity can pull it into a roughly spherical shape, but not large enough to clear its orbit around the Sun of other objects. As of 2011, there are five dwarf planets in the solar system: Pluto, Ceres, Eris, Makemake, and Haumea (which is not spherical, but is shaped more like an egg or a potato). Ceres is in the asteroid belt, while the others are beyond the orbit of Neptune, the eighth planet from the Sun.

Radio Programs

Quaoar Measuring a distance ice-ball Tuesday, March 11, 2014
Shrinking Iceball A distant iceball gets smaller Friday, October 19, 2012
New Dwarfs New neighbors in the outer solar system Saturday, June 11, 2011
Vulcanoid Zone Searching the "vulcanoid zone" Wednesday, December 15, 2010
Chippy Family Disrupting an icy world Friday, December 10, 2010
Orcus Giving birth to a distant moon Thursday, December 9, 2010


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