More Than Meets the Eye, Part I

1/14/07 – 1/20/07
by C. Zaitz

One of the more interesting facts about the night sky is that most of the stars you can see are not alone. Though they look like single points of light, there’s more than meets the naked eye. Some stars have companions that are too dim and small to see, and some have planets which are too dim and small to see. Either way, there is much more going on than we realize with those distant stars.

Our sun is one star that happens to sport planets. Planets are the result of a process that is not completely understood, so I will give you the short version, leaving out details in favor of getting the bigger picture.

A long, long time ago there was a cloud of gas and dust, the remnants of a star that once used to shine, but had long ago blown itself to bits and had created heavy elements in the process. This cloud was unimaginably huge, and all the little bits of it were moving in some direction. Eventually, the muddled bits tended to go in one direction in particular, flattened out, colliding and growing together under the force of gravity. Most of the bits came together in a great ball, which eventually became so massive that the inner bits were crushed and made to fuse, causing a chain reaction that produced prodigious amounts of energy. The sun was born.

Meanwhile, there was a still a great disk of gas and dust further out. The heavier stuff, like rocks and dirt and gold and silver, tended to be nearer the middle, forming the rocky inner planets. The lighter stuff, like hydrogen and helium and other wispy gases, collected further out in great blobs we call the gas giant planets. The little inner planets were heavy and cleaned up their orbits pretty well. Of the four planets, there are only three moons. Earth’s moon is the only respectable looking satellite, since Mars has two overgrown potatoes orbiting it.

Beyond Mars and the asteroids, things get more complicated. The four gassy planets developed rings and multiple moons. The rings are like millions of tiny, shattered ice moons. Some of the moons, and even some planets, have odd scars and orbits which indicate violent collisions, and possibly intense gravitational wars which have shaped the outer solar system. Recently, we have discovered a host of small bodies beyond Neptune which are now called dwarf planets. Pluto is of this realm, but more Pluto-like bodies are being discovered all the time.

As we look to other stars, we notice that a few hundred seem to have bodies orbiting them. These bodies are huge compared to our planets, but not big enough to be stars. Better telescopes will surely reveal smaller, more earth-like planets around stars. In fact, some astronomers estimate that nearly half the stars in the sky have planets. That’s a lot of planets. I wonder what those planets are like. Some are probably rocky and small like our earth. Will they house aliens? Will we someday meet Klingons? Or maybe the truth will be stranger than fiction. The exciting part is that someday we may be able to answer the question: are there aliens living on other planets. I hope the answer isn’t “no.” How dull!

Next week we will explore the strange multiple star systems that can also form instead of planets.

Until next week, my friends, enjoy the view.