22 Mar 2010
It is always about this time of the year that my astronomy class takes on Planet Earth. We've studied the evolution of modern astronomy from the days it was no more than glorified astrology to the high science it is now. We've observed the cosmos out to the "edge," delved into how stars are born, live, and die, and investigated the strange world of dark matter and supermassive black holes.
This week, though, one of my students will inevitably say, "I thought this was astronomy. Why are we now studying Earth?"
On the surface it seems like a legitimate question. "Aren't we supposed to be studying what is above our heads, not what's below our feet? What does our atmosphere or plate tectonics or volcanoes or earthquakes have to do with astronomy?"
An immediate, cold and rational answer would be that Earth is part of the universe. We are studying the universe. Hence, the earth would be included in our studies.
But it goes deeper than that, I believe. We can study our planet for philosophical reasons.
Let me give an analogy. Some of us go to the zoo and are satisfied with merely seeing some animals, spending time with loved ones, then getting home. Some spend time at the zoo actually observing the animals; how they move, how they are put together, how diverse they are in some ways, and how similar in others. These people might even go to the zoo without family or friends, if only to satisfy their great curiosity about the living realm around them.
But there are a few of us who go to the zoo and, after observing the animals, see something deeper. These people see that we ourselves, we humans, are in some ways connected to these other critters, but in other ways we are profoundly different. We don't walk out thinking only about where we are going to eat. We don't walk out thinking only that those peacocks sure were beautiful.
We walk out thinking we sure are special. And I do not mean that in an arrogant way. There is something deeply distinct about us humans in just about every aspect of life on earth. But until we know enough about those other critters - and know ourselves - we won't be able to see the truth: We are unique.
So after months of studying the diverse characters in the universe, the stars and galaxies and the vast empty space between them, its unimaginable violence and extreme danger, we come home to earth to study our planet with all its plates and water and continents and climates.
And when we study our planet in detail, we realize how truly unique and beautiful our home is. We are special. We are blessed. We can look around the universe, then see ourselves and proclaim that this earth is good. No! Make that "very good."
08 Mar 2010
Planet Round Up time! There are at least seven pesky planets moseying around up there. Let's go find them!
First let's track down and check off the planets that we will have the toughest time seeing due to that big bright plasma ball up there, namely, our sun.
You can just plain forget about seeing Neptune and Uranus. Both of those giant planets are on the opposite side of the sun and will not orbit around fast enough to see well anytime this month. Tiny Mercury is hiding behind the sun now, too.
There are two other star players near the sun now, as well. But they are not so close to our star that we cannot find them - if we know where to look.
Jupiter, because of our own speedy orbit, appears to be slipping closer to and behind the sun this month. Catch him now in the west after sunset; the Big Guy won't return until later in March in a new role as a "Morning Star."
Venus, that speedster, is whipping around the sun now at a good clip and is trying to pass Jupiter in the skies, going the other way, from our point of view. You will have a tough time seeing Venus this week since our hellish sister is still so close to the sun, but by next week she will pull away and be easy to spot.
Ready for a challenge? Go out next Sunday, the 14th, just 15 minutes after sunset and look towards where the sun has just set. There you will see two "stars." That would be Jupiter and Venus, a site which is pretty enough all by itself. If you look carefully just to the "right" of the two, you may see the faintest hint of the thinnest crescent moon. A thin crescent moon with a side of planets: what a combo!
So where is our other neighbor, our little buddy Mars? Mars, unlike Venus and Jupiter, is on the opposite side of the sky as the sun. So as the sun sets in the west, Mars is rising over in the east. It is relatively easy to see: It is pinkish, and a couple times brighter than any star near it.
Saturn is the only planet left. Like Mars, Saturn is on the same side of the sun as we. It will be rising in the 9 o'clock hour this week. Over the next weeks and months it will rise earlier and earlier, making it a better and better find as time go by.
However, because of unfortunate combinations of orbits and tilts, we are seeing the rings almost edge-on this year. That kind of takes away from their beauty. But hey, it's still Saturn, a handsome planet even with thinned-out rings.