Is Pluto a Planet or Is It Not? The Planetary Society Seeks Top 10 Lists

For Immediate Release
January 04, 2006

Mat Kaplan
Email: [email protected]
Phone: +1-626-793-5100

On January 17, 2006 the New Horizons mission will launch for Pluto, the last unexplored planet of the solar system -- or is it?

Some scientists now claim that Pluto does not deserve its planetary ranking, that it is instead a Kuiper belt object, one of many such bodies in the far reaches of the solar system. Many others, as well as much of the public, argue that Pluto is and always will be our ninth planet. While The Planetary Society can't control Pluto's status (that determination is controlled by the International Astronomical Union), we can expand the discussion about it. In honor of the launch of the New Horizons mission, the Society announces a call for the public to speak up and tell us:

The Top 10 Reasons Pluto IS a Planet, or
The Top 10 Reasons Pluto IS NOT a Planet

Even The Planetary Society's own Board of Directors is split, with Chairman Neil deGrasse Tyson wanting to demote Pluto from the planetary ranks and other members of the Board staunchly defending Pluto's status. In the interest of impartiality and public engagement, The Planetary Society is calling for reasons on both sides of the issue. For the next eight days, visitors to the Society's website can share their reasons why Pluto should or should not continue to be ranked as one of the solar system's nine planets. The deadline for submissions is Thursday, January 12, 2006. The final Top 10 Lists will be released prior to the launch of the New Horizons mission.

"Although the debate within the planetary community about Pluto's status is serious, the Top 10 Lists on our website do not have to be," said Bruce Betts, The Planetary Society's Director of Projects. "We will be looking for humorous rather than scientific reasons, although reasons that combine both would be a bonus."

Anyone, other than Planetary Society staff, Board and Advisory Council members, is eligible to submit entries to either or both of the Pluto Top 10 lists. Submissions are limited to five reasons per person per day for each list.

Read more on the Society's website about Pluto's status as a planet in essays by Tyson and the Society's Vice-President Bill Nye.

Whether you consider Pluto the last planet, the first Kuiper belt object, or something else entirely, the New Horizons mission will powerfully expand our scientific knowledge and the exploration of our solar system. Read more about this exciting mission.

About The Planetary Society

With a global community of more than 2 million space enthusiasts, The Planetary Society is the world’s largest and most influential space advocacy organization. Founded in 1980 by Carl Sagan, Bruce Murray, and Louis Friedman and today led by CEO Bill Nye, we empower the public to take a meaningful role in advancing space exploration through advocacy, education outreach, scientific innovation, and global collaboration. Together with our members and supporters, we’re on a mission to explore worlds, find life off Earth, and protect our planet from dangerous asteroids. To learn more, visit