Jimmy Westlake: New Horizons spacecraft zooms closer to Pluto
June 29, 2015
This is it — the event that I am most excited about in 2015.
On July 14, NASA's New Horizons spacecraft, after a nine-and-a-half-year journey, finally will fly through the Pluto system and reveal the mysteries of this misfit planet and its five moons to us at long last.
Pluto was discovered by American astronomer Clyde Tombaugh in 1930 and was immediately christened planet No. 9 in our solar system. Thus, it remained for the next 76 years.
Anyone older than 12 today learned in elementary school that our solar system has nine planets, Pluto being the smallest and most distant. In fact, when the New Horizons spacecraft was launched in January 2006, NASA billed it as "the first spacecraft to the last planet."
Then, in August 2006, Pluto was booted from the planet club when astronomers redefined the term "planet." Now, an object must meet three criteria to be labeled a planet.
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■ First, it must orbit a star directly. It can't orbit something else.
■ Second, it must be large enough to pull itself into a spherical shape with its own gravity. That usually requires a diameter of at least several hundred miles.
■ Third, it must be the dominant world in its neighborhood, having swept up all of the little guys around it.
It is this third criterion where Pluto falls short. We now know that Pluto is only one member of a large family of similar objects orbiting beyond Neptune in a region called the Kuiper Belt.
Our favorite little planet was demoted to "dwarf planet" status, along with four other mini-worlds: Ceres, Eris, Makemake and Haumea. As far as I am concerned, it's still the same old Pluto that we grew up with, no matter what we choose to call it today. Pluto remains a planet in my book.
Our best eye in the sky, the Hubble Space Telescope, can detect only vague light and dark markings on this distant, frozen mini-world, so when New Horizons blasts through the Pluto system July 14, we will get to know our favorite little planet's alien surface features for the first time.
What will we discover? I can't wait to find out.
Already, while still millions of miles away from Pluto, New Horizons is sending back tantalizing images of bright and dark areas on Pluto's surface. Soon, we will be receiving images that far surpass what Hubble has revealed.
You can keep track of New Horizons' progress and latest images at the NASA website nasa.gov/mission_pages/new
horizons/main/index.html. You can bet that the major media outlets will be covering the flyby on July 14.
Oh, by the way. Clyde Tombaugh died in 1997, but a small vial of his cremated mortal remains on board New Horizons will ensure that he is the first to visit the new world that he discovered. I'm hoping that the largest crater that New Horizons reveals on Pluto's surface will be named Tombaugh. It should be.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper and his “Cosmic Moment” radio spots can be heard on local radio station KFMU. Check out Jimmy's astrophotography website at http://www.jwestlake.com.