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

Comment on This Article

Science news

From The World's Science podcast to Nova, we'll deliver updates from these cutting edge programs. See a sample »


Support for WGBH is provided by:
Become a WGBH sponsor