New Horizons: Is Pluto a Planet? -- Brief discussion of the controversy, & suggested classification of 'Ice Dwarf' for Pluto, Charon, Sedna, & similar objects. Visit

IAU: Trans-Neptunian Object 2003 UB313 -- Re-announces formation of a working group to produce a formal definition of a planet, in conjunction with the announcement of this Trans-Neptunian object larger than Pluto, which will not actually be named pending a formal definition. (August 4, 2005) Visit

Astronomer Upset at New Planet Proposal -- Washington Post article describes Michael Brown's disagreement with a proposal to expand the definition of a planet to include, among others, his own discovery. (August 19, 2006) Visit

PBS NewsHour: Pluto Debate -- Reports regarding the controversy over Pluto's classification, focusing on pop culture influences & newsworthiness. (January 31, 2007) Visit

What is a Planet -- Reviews newly-discovered objects that stretch the definition of the term, including massive superjupiters, free-floating planets, and other exoplanets. So... Suggests a definition based on the way an object is formed. From astronomer Gibor Basri. Visit

Is Pluto a Giant Comet? -- Discusses related discoveries & excerpts. Visit

Gravity Rules: The Nature of Planethood -- Article discussing possible definitions that qualify objects, such as Pluto & Sedna in the Kuiper Belt, as being planets or not. Visit

Much ado about Pluto -- News release from NASA affirming Pluto's planetary status. (February 17, 1999) Visit

Pluto -- Argues that Pluto is the most important Kuiper Belt object, not the least important planet, based on its orbit & other properties. From astronomer Dave Jewitt, who studies comets & other primitive solar system bodies. Visit

SPACE.com: Pluto's Planet Status Could be Jeopardized by Sedna Discovery -- Discusses the ongoing debate over the definition of the term 'planet', & suggests that if Pluto should be actually considered a planet, so should Sedna & similar bodies. (March 17, 2004) Visit

National Geographic News: Pluto: Planet or Comet? -- Discusses Pluto's similarity to other Kuiper Belt objects, and introduces a 5-way classification scheme for solar system objects to break down the lumping together of dissimilar planets. (February 23, 2001) Visit

SciZone - Ontario Science Centre: Pluto: Planet or Not? -- Brief nontechnical introduction to Pluto & similar objects such as Sedna & Quaoar, & a summary of the features that make Pluto different than the other planets. Clear? Includes a capsule summary of the arguments for & against calling Pluto a planet. (April, 2004) Visit

Yes, Pluto Really is a Planet -- Argues that no commonly-accepted category fits it better… Includes a proposed definition of planet, and a list of known objects meeting it… From Lowell Observatory astronomer Marc W. Buie. Visit

IAU Resolutions 5&6 -- The International Astronomical Union's definition of a planet in the Solar System & ruling on the classification of Pluto.[pdf format] (August 24, 2006) Visit

CBS News: Pluto: Planet Or Junk Snowball? -- Outlines the history of the debate. (February 14, 2005) Visit