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good because the technology will be nine years out of
date by the time it arrives at Pluto.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!