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Star Search 1999

As Donald Brownlee watched from Kennedy Space Center in Florida last month, Stardust blasted into the heavens. It's not likely many observers considered the wistfully named mission's implications for the hunt for life away from Earth, but Brownlee certainly did.

The astronomy professor is among scores of faculty taking part in the Ãå±±½ûµØ's fledgling but groundbreaking doctoral program in astrobiology, the search for life on other celestial bodies, which begins this fall. He also is the principal investigator for Stardust, a seven-year mission designed to travel to comet Wild 2, capture samples of comet dust and bring them back for analysis.

This is a mission Brownlee has dreamed of since 1980. Technological advances and fortuitous events in space made it possible. In 1974, Wild 2 came close enough to Jupiter that the giant planet's gravity altered the comet's orbit around the Sun. Now instead of continuing to circle only among the outer planets of the solar system, it actually passes relatively close to Earth. Yet it hasn't been among the inner planets long enough for heat from the sun to have destroyed or altered telltale properties, characteristics Brownlee believes will provide new clues on the origins of the solar system and possibly the universe itself.

An artist's rendition of the Stardust spacecraft approaching comet Wild 2.

Last fall, as the Leonid meteor shower was concluding its annual display, an excited television reporter was in Brownlee's office. NASA had flown two planes high in the atmosphere to study Leonid particles and agency scientists noted the probable existence of organic properties. Brownlee reached into a file cabinet and withdrew a small rock, about the size of a charcoal briquette. This chunk, he announced, was about 2 percent carbon, was rich in organic material and was the first meteorite found to contain amino acids. It has been known for some time, he explained, that comets carry organic molecules.

They also carry water, a key component of life. It is thought that comets might well have deposited the first water on Earth, and perhaps the amino acids that evolved into life. If that is truly the case, then comets are a bit like Johnny Appleseed, wandering the universe and sowing the seeds of life as they go. Whether those seeds grow depends on the conditions they encounter after they are planted.

"The building materials are there, and then the question is, 'Does life occur?'" Brownlee said. "And who knows? I think most people believe that it's probably very common that if you have the right environment and you have the material, then life will evolve."-Vince Stricherz

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