NASA's New Horizons robot spacecraft is almost mid way on its nine-year deep-space voyage to the planet Pluto-ok, dwarf planet or Kuiper Belt Object or-whatever current buzz word you want to slug this fascinating world.
The plutonium-powered spacecraft, traveling at 47,000 mph, will flyby chilly Pluto in July 2015. If successful, it will be the first humanmade object ever to reach Pluto approximately 3 billion miles from Earth.
New Mexico astronomer Clyde Tombaugh discovered Pluto accidentally in 1930. I had the pleasure of meeting and chatting with Tombaugh in 1977 at a meeting of the Lehigh Valley Amateur Astronomical Society in Allentown, Pa. Tombaugh was a gentle and humble man. I think he would be proud of the New Horizons mission to reach this smallest of planets.
Pluto is the farthest, large planetary body from our Sun. Occasionally, Pluto gives up this position to Neptune due to the unusual, elliptical Plutonian orbit. A year on Pluto lasts 248 terrestrial years.
In 2000, after scrubbing its Pluto Fast Flyby, later renamed Kuiper-Pluto Express mission, space agency officials were forced to reconsider their mistake when many scientists and vocal pro-space groups protested loudly. "We have to get to Pluto quickly," the experts claimed. So, from the ashes of the PFF/KPE mission was born New Horizons. But what's the hurry and why should we visit Pluto now, you may ask?
As it moves away from the Sun, Pluto's atmosphere will re-freeze falling to the surface as a nitrogen-carbon dioxide-methane snow sometime around the year 2020. Hence, scientists are anxious to get to Pluto now, while it still has a gaseous atmosphere. Missing the January-February 2006 launch date would have meant waiting until the year 2200 when Pluto's long-sleeping atmosphere sublimes back from ice to gas.
What will we find when we finally visit Pluto?
Being almost 6 billion km from the Sun, the rock and ice-bound planet's surface must be terribly cold, colder than liquid nitrogen. Estimates place Pluto's surface at a cryogenically chilly minus 396 degrees Fahrenheit. That's cold enough for water ice to act like rock. But the warmer interior protected by miles of thick nitrogen, methane and carbon monoxide ices, and heated by radioactive rocks at the planet's core, may support a deep layer of liquid water-a Plutonian ocean. It's fun to speculate what life forms might have evolved in that Stygian sea.
Any future astronauts landing on Pluto will stand on the frontier of the solar system. They will see the dwarf planet's cratered moon Charon looming large in the sky. Inward, toward the Sun, our feeble home star will appear much like Venus does from Earth. There will be no warmth from its rays. Outward, the explorers will gaze into an immense gulf of interstellar space.
What's in the Sky: Check out Plaskett's Star, the most massive binary sun known. The primary masses at 40 suns, the companion about 60 suns; in the southeast after 7 p.m. The first week of February is a good for the planet Mars. On Jan. 29, Mars was at opposition (opposite the Sun). While not as bright as during other oppositions, Mars doubled in brightness since Dec. 1 Sirius an and Jupiter are brighter. Mars rises in the east after sunset. Star chart courtesy of J. Kirk Edwards.
Lou Varricchio, M.Sc., lives in Vermont. He was a former science writer at the NASA Ames Rseracg Center in California and is a member of theNASA/JPL Solar System Ambassador. He is the recipient of the U.S. Civil Air Patrol's Brig. Gen. Chuck Yeager Aerospace Education Achievement Award. Interested in a presentation about space at your school or organization? Call Varricchio at 388-6397 or e-mail him at: email@example.com