by Robert Freeman

Created on: January 17, 2010   Last Updated: April 26, 2010

On a cold night in Flagstaff, Arizona at the world famous Lowell Observatory one man made a discovery that hundreds of astronomers before him had try to do every time they looked into their high-powered telescopes. The night was February 18, 1930, the man was Clyde Tombaugh who was only 23 years old, and the discovery was the ninth planet in our solar system; Pluto. For 76 years Pluto circled the Sun with the label of planet, but on September 13, 2006 Pluto fell from the International Astronomical Union’s (IAU) graces and was re-labeled.

Since 2006 the world has been unable to reach a consensus on what Pluto really is and the debate continues to this day. There are many different labels being thrown around for Pluto to include planet, dwarf planet, Trans-Neptunian object, Kuiper Belt Object, minor planet, plutoid, and Disney character. Little yellow dog that is a pet of Mickey Mouse aside (which was actually named after the “planet”), all of the above labels have and continue to be used for the ball of ice that circles the Sun on a highly elliptical orbit but which one is it?

International Astronomical Union's Change of Heart

The truth is the international astronomy community can’t reach a decision so in reality the answer truly depends on which side of the debate you find yourself to be on. For the purposes of this article the author will explain the IAU’s stance and provide the most respected arguments against this stance and let the reader decide what they believe Pluto really is.

For starters it must be made clear that in 1930 it was the IAU that agreed that Pluto be included in the list of planets in our solar system and accepted the name Pluto from a suggestion of an 11 year old girl in the United Kingdom. This same organization supported the decision to remove the “asteroid” Ceres from the list of planets which it was on for around 50 years during the 19th century and is the same group that removed Pluto from the list of planets after it too was on the list of planets for over half a century.

Discovery of Kuiper Belt Started It All

Prior to the controversial 2006 decision Pluto’s standing as a planet had been in question with the discovery of the Kuiper Belt and other large objects in orbit around the sun beyond the orbit of Neptune. As a matter of fact around 2000 many models of the solar system began to change and many academic institutions and planetariums had scale models of the solar system with only

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