Marc Buie of the Lowell Observatory describes observations of Pluto in 1996 and their comparison with the 1994 observations that were reported in a 1996 press release. They showed structure on Pluto's surface. He has also compiled a list of "good Pluto WWW Pages," assigning grades of A+ to C for them.
JPL continues to plan a Pluto Express mission to arrive at Pluto approximately AD 2010 to make close-up observations and to measure Pluto's atmosphere before it freezes out and settles onto the surface.
The discovery of over a dozen objects orbiting the Sun beyond Neptune's orbit makes Pluto less special. The observational status of Pluto is discussed in the text, as well as the question "Is Pluto a Planet?" Over a dozen published sources refer to Pluto as something less than a planet, but Clyde Tombaugh is quoted in a summary article in USA Today (March 4, 1996, pp. 1-2) as saying "Pluto is far bigger than any asteroid.... The kids want Pluto to be a planet. I get hundreds of letters. [Talk of demoting Pluto] makes them mad."
My own position? I have an interest in history and historical astronomy, and that sways me to the side of still saying that we have nine planets, with Pluto as one of them.
Kaare Aksnes, president of the International Astronomical Union's panel on nomenclature, is quoted in the same USA Today article as saying, "I'm pretty sure all the members would be against demoting Pluto in this way." Even though the latest data minimize the importance of Pluto on a planetary scale, Aksnes continues, "we would do Pluto and Tombaugh an injustice and create confusion if we were to reclassify Pluto now. I believe that most people, be they astronomers or not," would agree." Though the Aksnes committee does not actually have authority to decide the issue, it is perhaps the nearest to the topic of IAU committees.
The Hubble Space Telescope has imaged Pluto for the first time at sufficiently high resolution that we can see surface features. The resolution on Pluto is about 100 km, so there are two dozen pixels across the image. The two views show opposite hemispheres. We cannot know exactly what the dark and light areas are. They may be basins or impact craters. Probably, most of the light regions on the surface are regions of frost. These regions would change with Pluto's seasons.
A movie is also available showing Pluto's rotation.
Credit: Alan Stern (Southwest Research Institute), Marc Buie (Lowell Observatory), NASA and ESA
Fran Bagenal at the University of Colorado has assembled a World Wide Web homepage for Pluto, giving both history and current science. Links are also provided to other Pluto homepages, including the Jet Propulsion Laboratory's Pluto Express, the Pluto subsection of the Los Alamos National Laboratory's set of planet homepages, and maps of Pluto and Charon computed by Marc Buie of the Lowell Observatory.
