Update: September 20, 2006 
VISITING PLUTO ANYWAY
By Pam Eastlick for THE DEEP on line

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond. I suspect most of you read my column on 28 August when I talked about poor little Pluto being booted out of the planetary society and made to go play in the Little Leagues again. (If you missed the column, you can find it HERE or the UOG Planetarium website).

This decision by the IAU has generated a lot of controversy, especially among astronomy educators. The discussion on my Planetarium listsers got so acrimonious that I winced every time I opened the messages. Of course, as I tell the children, we humans have a very exaggerated view of our importance in the overall scheme of things. Pluto doesn’t care if we call it a planet, a small solar system body, an asteroid or late to dinner. All of these designations are solely for the benefit of humans and have absolutely nothing to do with the bodies in question.

What is important is learning new things and even though Pluto has been ‘demoted’, the New Horizons spacecraft is still traveling there at the fastest speed possible. It will still take nine years to get there because Pluto is over 4 billion miles away.

I said in an earlier column that “Pluto is very small (less than half the size of our Moon) and there’s a strong possibility that it isn’t a planet at all.” I can pat myself on the back because the IAU agreed with me, but the main reason Pluto was reclassified (NOT demoted) is that astronomers have begun to discover many more Pluto-sized objects in the empty regions beyond Neptune and Pluto is probably only one of a host of asteroids in the Kuiper (Ky-per) Belt. The New Horizons spacecraft has state-of-the-art instruments, which is good because the technology will be nine years out of date by the time it arrives at Pluto. The people who will guide the robot at the end of its mission are probably still in high school and college right now. One of the things I love about the New Horizons mission is that its instruments have been given very whimsical names. They are Ralph, Alice, Rex, Lorri, Pepssi, Swap and SDC.

Ralph is the visible and infrared spectrometer and Alice is the ultraviolet spectrometer. These instruments will tell us what chemicals make up Pluto and its moon Charon. Rex will measure the atmospheric composition of Pluto (assuming Pluto has an atmosphere) and will also take Pluto’s temperature. As near as we can tell from Earth, a balmy summer day on Pluto is around minus 365 degrees.

Lorri is the telescopic camera that will return the visual images that are the most important part for us non-scientists. Pluto is so far away our best resolution photos show only blurs of light and dark. SWAP will measure the solar wind around Pluto and the little world’s interaction with it. And since the solar wind is made of particles of the Sun, even at 4 BILLION miles away, Pluto, like the rest of the solar system, is technically inside our star.

Pepssi (Pluto Energetic Particle Spectrometer Science Investigation) will measure the composition and density of ions escaping from Pluto's atmosphere and SDC is a real triumph of human endeavor. It’s the Student Dust Counter and it was built and operated by students at the University of Colorado. The instruments job is to measure the space dust peppering New Horizons during its voyage across the solar system.

So why would we spend $750 million to visit something that small and that far away? And why are we still doing it when Pluto isn’t a planet anymore? Well, even in the midst of conflict and natural disaster, the scientific quest to understand the universe and humanity's place in it goes forward. Our commitment to exploration and the gathering of new knowledge is a worthy investment. It says much not only about us, but also about the human condition. Animals don’t reach for the stars.

I suspect that once New Horizons reaches Pluto, assuming it’s still in good shape, they may send it out to look at some of the other Kuiper Belt objects. Our great-grandchildren may learn things from this amazing robot. Science is all about change. We may not think Pluto is a planet anymore, but that doesn’t mean that it’s not worth exploring. Cruise well, New Horizons. We expect great things!