Pluto Tries To Hold On
The Solar System >
For being a nice little ice rock 2900 million miles away, wee Pluto sure has been making the news lately. Why, it's almost as if it senses it may be losing its status as a planet and is making every attempt to make us believe that it is no different from its neighbors - maybe just smaller.
Discovered by Clyde Tombaugh less than hundred years ago, Pluto has always been an enigma of sorts. Before its discovery there were all these monstrous planets in the outer system; Jupiter and Saturn had been known since time immemorial, then with the coming of telescopes Uranus and Neptune were discovered in the 18th and 19th centuries.
They were huge and gassy and floating around the sun nicely with the rest of us.
Then along comes tiny Pluto. It was no bigger than our country, made mostly of water ice, and had an orbit so tipped over and egg-shaped - not the nearly circular orbit of its neighbors - that you'd think it had been adopted into our system rather than born with the rest of the brood.
But it was categorized as a planet anyway and got its own special name.
But now things have changed. There's a new set of animals in the zoo and Pluto may actually be one of them instead.
It was proposed over in the mid-1900's that there might be a belt of leftover stuff from the creation of the solar system, wannabe planet material, in a vast donutlike cloud of icy debris extending from Neptune out another several billion miles, in an area often called the Edgeworth-Kuiper Belt.
But it wasn't until 1992 that technology caught up with theory and we could actually see one of the debris bits. And then another was found, then another, then another. Now we have seen over 800 of these Kuiper Belt Objects. Now we have a dilemma.
Some of these KPO's are actually bigger than Pluto!!! Are they, too, planets? Or was Pluto perhaps just the first Kuiper Belt Object discovered?
Perhaps fearing it may lose its planet status, Pluto isn't going down without a fight. In just the last year, it has recently revealed previously unknown secrets of itself.
Pluto has a moon, Charon, discovered in 1978, over half the size of Pluto. The two are essentially a double planet. But just last year two more icy little guys, measuring just over 30 miles across, have been seen orbiting Pluto. Pluto has a least 3 moons!
Some believe that these moons, including Charon, were formed when Pluto got clocked real badly some time ago by an impacting object. This collision sheared off what became Charon and the two new moons.
This hypothesized collision may also have put enough fine debris into the vicinity for Pluto to actually have formed a wimpy ring system of its very own!
Multiple moons? A ring system? You can almost hear little Pluto crying out, "I am a real planet! I am a real planet!"
Whether or not the International Astronomical Union changes the status of Pluto in the coming months, maybe it's a win-win situation for the Little One.
If it remains an official "planet" it will still be part of the Elite Nine. Yippee for all traditionalists!
But if it turns out that Pluto is reclassified as a Kuiper Belt Object, that's OK, too. It was the first one discovered, it's the nearest one to the inner solar system, and the first one to have a spacecraft sent to it. It is would be then the premiere Kuiper Belt Object in a field of millions.
Until next time, clear skies!
Mark Ritter teaches astronomy in Temecula, and free podcasts of The Skies Above column can be found online at the iTunes Music Store.
Posted by Mark Ritter at 2006.03.19 11:15 AM | Comments (0)
