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Seeking the Farthest Planet
Week of August 31-September 6, 2014
Scientists are in the business of classifying things. They classify everything from butterflies to rocks to clouds to stars. And sometimes, when new data or understanding becomes available, they must go back and re-classify things to make them better fit the scheme.
So it should have come as little surprise to anyone who follows science that, a few years ago, astronomers reclassified Pluto — that tiny little ice ball near the edge of our planetary system — as a "dwarf planet." And Pluto's reclassification out of official planet-hood means is that the honor of being the most distant planet from the sun now belongs to Neptune.
Neptune was discovered after astronomers learned that the planet Uranus — which William Herschel had found six and a half decades earlier — exhibited some odd orbital behavior. In other words, Uranus didn't keep to the precise path sky watchers had expected.
A young English astronomer named John Couch Adams calculated that the motion of Uranus was apparently being affected by another world that lay beyond and its gravitation was tugging on it. Adams even figured out where this unknown planet might appear; unfortunately, no one in England ever bothered to look for it.
The same was true in France where Urbain Leverrier independently made the same calculations. Again, no one seemed to care.
But Leverrier didn't give up. He showed his calculations to the German astronomer Johann Galle who aimed his telescope skyward and found the new planet — eventually named Neptune — on his very first night of searching!
That was in 1846 and, since then, few beginning stargazers have ever even looked for this distant world.
Finding Neptune among the faint stars of Aquarius isn't easy, however, and since this distant world is invisible to the unaided eye, you'll need to use "star hopping" techniques, as well as have a very dark rural sky, binoculars and patience in order to spot it.
First find the faint stars Ancha and Tau Aquarii in Aquarius, and then locate the star Sigma Aquarii almost midway between them. If you aim binoculars in its direction, you should find Neptune as a much fainter "star" less than one degree to its left. A small telescope aimed in its direction will show a distinctive bluish-green hue that distinguishes it from neighboring stars.
If you're not sure you've found it, make a sketch of the area, being careful to mark the stars in their exact positions. Then, a week or two later, check out this same region of the sky and see if any of the objects has changed its position. That's Neptune!
If needed, you can find a more detailed finder chart for the planet here: www.nakedeyeplanets.com/neptune.htm.
As tiny and faint as it appears — and as challenging as it might be to find it — there's something really cool about standing under a dark, starry sky and seeing with our own eyes the farthest planet of our solar system!
Visit Dennis Mammana at www.dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.
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