The Dwarf Planet Pluto
The Illinois 96th General Assembly (2009-2010) fresh from demoting Governor Rod Blagojevich to non-governor status is out to balance things out by promoting Pluto back to planetary status. Clyde Tombaugh (1906-1997), the man who discovered Pluto on January 23, 1930, was born in Illinois. Up until the time that the International Astronomical Union demoted Pluto to a dwarf planet (2006), not only could the United States boast of having a native born planet discoverer but so could Illinois. Being a native Illinoian myself I rather liked that. I even had the honor of meeting Clyde Tombaugh quite a few years ago and have an autographed copy of his book Out of Darkness: The Planet Pluto, co-authored with Patrick Moore.
Up until the International Astronomical Union’s 2006 meeting there had never been a formal definition of just what constituted a planet - it was one of those intuitively obvious things. The discovery of 2003 UB313 was the straw that broke the camel’s back. 2003 UB313 was larger than Pluto! What to do? To declare 2003 UB313 a planet would have opened the door to defining Ceres and other like sized objects as planets. It was felt that there was a need for a new category of objects, with size being just one of the factors. The result was a new class known as dwarf planets, of which there are now five members:
- Ceres
- Eris (aka 2003 UB313)
- Haumea
- Makemake
- Pluto
In order to reclaim one of Illinois’ claims to fame there is a resolution in the Illinois Senate calling for Pluto to be considered a planet and that March 13, 2009 be declared “Pluto Day” here in Illinois. Following is the resolution that is currently before the Illinois Senate.
SENATE RESOLUTION SR0046 LRB096 04130 KXB 14171 r
WHEREAS, Clyde Tombaugh, discoverer of the planet Pluto, was born on a farm near the Illinois community of Streator; and
WHEREAS, Dr. Tombaugh served as a researcher at the prestigious Lowell Observatory in Flagstaff, Arizona; and
WHEREAS, Dr. Tombaugh first detected the presence of Pluto in 1930; and
WHEREAS, Dr. Tombaugh is so far the only Illinoisan and only American to ever discover a planet; and
WHEREAS, For more than 75 years, Pluto was considered the ninth planet of the Solar System; and
WHEREAS, A spacecraft called New Horizons was launched in January 2006 to explore Pluto in the year 2015; and
WHEREAS, Pluto has three moons: Charon, Nix and Hydra; and
WHEREAS, Pluto’s average orbit is more than three billion miles from the sun; and
WHEREAS, Pluto was unfairly downgraded to a “dwarf” planet in a vote in which only 4 percent of the International Astronomical Union’s 10,000 scientists participated; and
WHEREAS, Many respected astronomers believe Pluto’s full planetary status should be restored; therefore, be it
RESOLVED, BY THE SENATE OF THE NINETY-SIXTH GENERAL ASSEMBLY OF THE STATE OF ILLINOIS, that as Pluto passes overhead through Illinois’ night skies, that it be reestablished with full planetary status, and that March 13, 2009 be declared “Pluto Day” in the State of Illinois in honor of the date its discovery was announced in 1930.
One bit of misleading information is the point that only 4 percent of the IAU’s 10,000 scientists voted. One thing that must be noted is that IAU membership is for life so included in the total membership number are those individuals who are no longer active in either astronomy or the IAU.
Due to the diverse nature of its mission and the different fields of science involved, the IAU is organized into 12 Divisions, 40 Commissions, and 71 Working Groups and Program Groups. The division that deals with planetary science is the Division III Planetary Systems Sciences which has approximately 1,000 members (active and retired).
So while the vote was open to all attending members, only a fraction would have had a direct interest in the outcome of the vote. It is also interesting to note that the outcome of the official vote was similar in proportion to that of a straw poll of Division III Planetary Systems Sciences members that was conducted earlier that day.
I am all in favor of having a “Pluto Day” and acknowledging the accomplishments of Clyde Tombaugh. This is especially appropriate as 2009 is the International Year of Astronomy. However when it comes to deciding whether an object is a planet or not, I put my faith in the International Astronomical Union and not Illinois politicians.
About the Pluto Illustration
To create the illustration of Pluto for this post I began with an albedo map taken from a Hubble Space Telescope image. I then created a grayscale texture for the planet’s, oops make that dwarf planet’s surface. I then used hue/saturation and levels adjustment layers to further manipulate the texture and layer styles to fuzz up the dwarf planet’s limb. All work was done using Adobe Photoshop.
If you live in Illinois, I encourage you to contact your state Senator and let them know that you are in favor of honoring Clyde Tombaugh and Pluto but I leave it for you to decide whether to support or oppose the attempt to have Pluto classified as a planet.
Ad Astra, Jim
