Date: February 28, 2011
Title: Why Isn’t Pluto a Planet?
Podcaster: The Astronomy Cast Team of Fraser Cain and Dr. Pamela Gay
Organization: Astronomy Cast – www.astronomycast.org
Description: A short explainer on why Pluto is no longer a planet. If you’re friends have cornered and asking you technical questions on why Pluto isn’t a planet, you can point them here and let Fraser and Pamela set them straight. This podcast originally aired on April 18, 2009.
Bio: Fraser Cain is the publisher of Universe Today and Dr. Pamela Gay is a professor at Southern Illinois University-Edwardsville. They team up to do Astronomy Cast, a weekly facts-based journey through the cosmos.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2011, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at signup@365daysofastronomy.org.
Transcript:
***Transcript coming soon.***
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365 Days of Astronomy
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Pluto is very much a planet, and I encourage everyone to hear both sides of this ongoing debate before blindly accepting one interpretation as fact. Hundreds of professional astronomers led by Dr. Alan Stern, Principal Investigator of NASA’s New Horizons mission to Pluto, have formally rejected the demotion of Pluto, which was done by only four percent of the IAU. Stern and like-minded scientists favor a broader planet definition that includes any non-self-luminous spheroidal body orbiting a star. That gives our solar system a potential of 60+ planets. The term dwarf planet was created by Dr. Alan Stern in 1991 to indicate a third class of planets in addition to terrestrials and jovians, small planets large enough to be pulled into a round shape by their own gravity but not large enough to gravitationally dominate their orbits. He never intended for dwarf planets to not be considered planets at all. And interestingly, the premise that led the IAU to feel a need to define planet–that Eris is larger than Pluto–was shown to be false when Eris occulted a star in November 2010.
I encourage readers to learn both sides of the story. Two good books on the pro-Pluto as a planet side are “Is Pluto A Planet?” by Dr. David Weintraub and “The Case for Pluto” by Alan Boyle.