Image List
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On Sept. 18, 2014, audience members who attended the Observatory Night talk "What is a Planet?" voted to choose one of three possible definitions for a planet. The result: a planet is "the smallest spherical lump of matter that formed around stars or stellar remnants," and Pluto IS a planet!
Harvard-Smithsonian CfA -
Pluto (left) and Charon (right) dominate this view of the outer solar system. Charon is about half the size of Pluto. Pluto also hosts four tiny moons - Nix, Hydra, Kerberos, and Styx - two of which are seen as small crescents at top left and right. In the distance, a faint Sun illuminates dust within the asteroid belt.
David A. Aguilar (CfA)
