From Laurel Kornfeld:

Re: Solar system’s distant ice-rocks come into focus (Sept. 14, 2010): I am a writer, amateur astronomer, and astronomy graduate student writing in response to your article “Solar System’s Distant Ice Rocks Come Into Focus.” Specifically, I am writing to object to your listing of Neptune as the solar system’s most distant planet and description of Pluto as a former planet. This represents only one point of view in an ongoing debate. Only four percent of the IAU voted on the controversial demotion, and most are not planetary scientists. Their decision was immediately opposed in a formal petition by hundreds of professional astronomers led by Dr. Alan Stern, Principal Investigator of NASA’s New Horizons mission to Pluto. One reason the IAU definition makes no sense is it says dwarf planets are not planets at all! That is like saying a grizzly bear is not a bear, and it is inconsistent with the use of the term “dwarf” in astronomy, where dwarf stars are still stars, and dwarf galaxies are still galaxies. Also, the IAU definition classifies objects solely by where they are while ignoring what they are. If Earth were in Pluto’s orbit, according to the IAU definition, it would not be a planet either. A definition that takes the same object and makes it a planet in one location and not a planet in another is essentially useless. Pluto is a planet because it is spherical, meaning it is large enough to be pulled into a round shape by its own gravity--a state known as hydrostatic equilibrium and characteristic of planets, not of shapeless asteroids held together by chemical bonds. These reasons are why many astronomers, lay people, and educators are either ignoring the demotion entirely

In writing about the outer solar system, I urge you to, rather than portray one view of the debate as gospel truth, note that the status of Pluto and of all dwarf planets remains a matter of contention on which there is no consensus among astronomers.

The following links should be of assistance in demonstrating this:

Petition of professional astronomers who opposed IAU decision:
http://www.ipetitions.com/petition/planetprotest/

The Great Planet Debate, held at the Johns Hopkins University Applied Physics Lab in August 2008 in response to the IAU decision:
http://gpd. jhuapl. edu/

My four-year-old blog advocating the planetary status of Pluto and all dwarf planets and chronicling worldwide efforts toward that end:
http://laurele. livejournal.com

-Laurel Kornfeld

Highland Park, NJ

Graduate student in astronomy, Swinburne University Astronomy Online program