What defines a planet: The Star Trek Test

Feb. 14, 2012


"Eight Planets and New Solar System Designations" from NASA Images

Alan Stern is a Planetary Scientist at NASA and has led many planetary and lunar missions, including the New Horizons Pluto-Kuiper Belt mission, a robotic spacecraft on its way to explore the dwarf planet Pluto. He talks about what qualifies an object in space as a planet.

NOVA: The Pluto Files
NOVA: 10th Planet
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