19 Mar 2006
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!
05 Mar 2006
So you want to know what that bright light is hovering mysteriously in the eastern predawn skies, the light you could swear wasn’t there just months ago.
I thought you’d never ask!
For early risers, those who must send kids off to school or get early onto those maniacal freeways of ours, there has been a shimmering orb that rises before the sun and has been entertaining us since the beginning of January.
Why, it appears to be a star! A wandering star, to wax poetic about it, the way it changes position through the weeks. And it was once believed to be just that – a star that roamed, not one fixed onto the heavens above like all those other pricks of light that trustily return to their same positions night after night, month after month, year after year.
The Greeks gave this heavenly body and a half dozen more the name “wanderer” - in Greek “planetes” - which we formed into “planet.”
Of course, the big bright one now gracing our skies, the brightest of them all, is Venus, our nearest but not so dearest neighbor.
At the moment she is a mere 49 million miles away from us, a stone’s throw in cosmological terms. And right now, unknown to many, there is a spacecraft headed her way.
The European Space Agency is sending the Venus Express there to study that bizarre, twisted sister of ours. Scheduled to enter Venusian orbit just a month from now, it will study the hellish surface of the planet and its bizarre climate.
What is so outlandish about that pretty addition to our morning commute? Hmmm… let’s see. Try everything.
Yes, she is the same size and mass and density as our planet, but that’s it as far as being our twin. This dysfunctional sibling of ours has all the earmarks of being designed for the devil himself.
The surface temperature is about 900 degrees Fahrenheit. Check your stove now and see that it can’t get above about 500 Fahrenheit at full blast. It’s just a little toasty on the Bright One.
And if you could land on its surface you’d be subject to pressures that are nearly 90 times that of our own atmospheric pressure. That’s like being a kilometer under water. I don’t know about you but I get all whiney with the crushing pressure that comes in diving into the deep end of a backyard pool, let alone more than a half mile down into an ocean. And we’re talking only of Venus’ atmosphere, its “air”!
The Soviet spacecraft sent there in the 1980’s could survive only an hour on the surface before Venus claimed it as its latest victim.
The choking, cloud covered atmosphere of Venus is so unbelievably thick that only the biggest rocks can plummet from space through to the surface. That’s why we see no craters there smaller than about two kilometers. Those poor wannabe impactors were burned up in the beefy atmosphere, or broke apart into a million pieces before reaching the face of Venus.
And even if you manage to make it through the thick sulfuric acid clouds, through the sea of baking carbon dioxide gas, and hit the surface – even if you manage to make an impact and leave your mark on that bleeding hot facade, odds are your grave won’t be marked for long.
It appears that the surface of Venus, unable to release its internal pressures from below slowly and regularly like our planet does, lets it all off at once. This amounts to what astronomers believe is a massive global volcanic phenomenon that completely resurfaces the face of the planet, obliterating all signs of previous impacts. Yeah, there’s a fun place.
Ideally the Venus Express will help us understand that beautiful diamond in the sky a lot better. What happened to all her water? What happened there early on to give Venus such a vastly different outcome? When and why did things so horribly bad?
Whatever we learn by delving deeper into Venus one thing is for sure, it will make me appreciate our beautiful Blue Wonder even more.