Friday, June 13, 2008

Plutoids - by Brad

It was almost two years ago that I blogged about the demotion of Pluto to a new category of "dwarf planets". When this term was coined, there were three official dwarf planets; Pluto, Eris (another Pluto-like object way out there), and Ceres (a round asteroid between Mars and Jupiter).

A couple days ago, the International Astronomical Union issued a press release that they are dropping the title of "dwarf planet" and adding a new definition of "plutoid". These plutoids will consist of the larger objects orbiting way out there like Pluto and Eris. Therefore, poor Ceres is now unclassified. I guess since Ceres is the only one of its kind they don't care to classify it.

This step makes sense to me. I like that we can now say we just have 8 planets in our solar system. We shouldn't have to mess around with explaining dwarf planets. If we want to address Pluto, it can be lumped in with the other plutoids that are in a large asteroid belt on the outside of the solar system.

Image from IAU press release

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