Dwarf Planet
From Slackerpedia Galactica
A much maligned sub-class of objects in the Solar System first defined in 2006. Too small to be planets, too big to be small Solar System bodies, but just right to get the attention of astronomers and the IAU.
A planet is supposed to be a round, lonely object that orbits the Sun. Dwarf planets do not fit this description because, despite being round and going 'round, they are quite social. Usually found in hopping places like the Asteroid Belt and Kuiper Belt, dwarf planets are something like the popular "big men on campus" in their respective orbits- they're never found alone, and while they're popularity may prove fleeting, they somehow seem more important than the riff raff that follows them around.
According to the International Astronomical Union (IAU) - or at least a small part of the body - A Dwarf Planet is a celestial body that:
- Is in orbit around the Sun.
- Has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape.
- Has not cleared the neighbourhood around its orbit.
- Is not a satellite.
Initially, the only official dwarf planets were Ceres, Pluto and Eris but the group likely consists of dozens, if not hundreds, of individuals... we just haven't found them all yet.
In mythology, dwarves are a legendary race of short humanoids. They too are occasionally found in groups (most notably in a group of seven). Dwarfism is also a genetic condition that can be expressed in all living creatures. While biology's dwarfs are grouped together with larger members of the same species (or genus or family or something... this isn't a biology encyclopedia), astronomers would like you to believe that dwarf planets are not planets at all. Perhaps this is supposed to be ironic, but it all just seems very confusing.
Contrary to popular belief, there are not seven of these objects, and they are not named Doc, Grumpy, Happy, Sneezy, Bashful, Sleepy & Dopey.
