Exploring the final frontier

NASA's romantically named New Horizons is well on its way to the distant dwarf-planet Pluto. The plutonium-powered spacecraft, traveling at 47,000 mph, will flyby chilly Pluto in July 2015. If successful, it will be the first manmade object ever to reach Pluto which swings between 2.7 and 4.5 billion miles from the Sun.

New Mexico astronomer Clyde Tombaugh discovered Pluto accidentally in 1930. I had the honor of meeting and chatting with Tombaugh at a 1977 meeting of the Lehigh Valley Amateur Astronomical Society of Pennsylvania. 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 one of 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 so-called 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," many 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?

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.

What will we find when we finally visit Pluto?

Varying in its elliptical orbit between 2.7 and 4.5 billion miles 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.

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