Commentary by Roger Martin Martin writes about research at KU for Kansas media and in a Web zine. Contact Martin at rmartin@kucr.ukans.edu or (785) 864-7239. Martin also can be heard on KANU 91.5 FM public radio Archives More articles by Roger Martin Subscribe now to receive KU News by email

Knowledge of solar system has changed in past 40 years

by Roger Martin

Forty years ago, astronaut John Glenn orbited the Earth, the first American to fly so high. Since then, we've probed the solar system with a bevy of spacecraft: Mariners and Vikings and Pioneers and Rovers.

The practical benefits of our voyages are nothing to sniff at. We've monitored the ozone hole over Antarctica, figured out the shape of ocean basins, predicted the weather. We developed space blankets and wireless technology and new materials. Oh yeah, and an orange-flavored drink called Tang.

Although our feet remain planted on terra firma, we have come to know our planetary neighborhood for the very first time. Tom Armstrong, a University of Kansas professor of physics and astronomy, can list all kinds of changes in our thinking.

Just 25 years ago, for example, we believed Saturn to be the only planet with rings. Today we know that Uranus, Neptune and Jupiter also wear these rocky girdles.

Space probes changed entirely our picture of Venus. For a while Venus was thought to be warm, swampy and dabbed with primitive life; for another while, blanketed by oceans. But space probes showed it was a 900-degree hell, Armstrong says, hotter than the planet Mercury even, with not a drop to drink -- anywhere.

And Jupiter -- now there's a trip. Armstrong says, "It's likely that Jupiter doesn't have a 'surface' in the usual sense. The gases may just get thicker and thicker and thicker."

The enormous atmospheric pressures on Jupiter may turn the hydrogen in its atmosphere into something that would behave like a metal without being a metal. Wrap your mind around that.

Or how about Saturn? It's the least dense of the planets. If you had a bathtub big enough to hold it, Saturn would float.

The surprises go way beyond gee-whiz facts about the planets. One of the most staggering things to Armstrong is how un-empty space has turned out to be. It's brimming with thin, hot gas and cold dense gas -- dust and magnetic fields and fast cosmic rays.

Gusts of high-energy particles ride outward from the sun on the broad back of the solar wind. From the opposite direction -- the depths of interstellar space -- come helium and oxygen and other elements. When these groups of particles collide, the interstellar matter rockets back to the edge of the solar system, hits an invisible wall, then returns, its energy boosted incredibly.

The fact that the solar system leaks and allows material to enter it from interstellar space opens up a fascinating possibility, Armstrong says. "Every now and again," he says, "you hear speculation that life didn't arise spontaneously on Earth, that it floated in from interstellar space. This used to be regarded as the lunatic raving of people who took science fiction too seriously. Now the idea is not quite so disdained."

So thank you, astronaut John Glenn, for your daring 40 years ago, for your high-flying ways. Thank you for putting a face on a space program that has not only put Tang in our lives but also made it respectable to entertain lunatic thoughts. After all, it's surprising how often "lunacy" serves human advancement.