Astronomers Search for Signs of Life in the Skies of Distant Exoplanets (preview)

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The galaxy is teeming with planets. Scientists are straining to peer into their atmospheres to seek signs of extraterrestrial life

By Michael D. Lemonick

Image: COURTESY OF EUROPEAN SOUTHERN OBSERVATORY

In Brief

• Common wisdom once held that it would be nearly impossible to investigate the atmospheres of distant exoplanets?the glare from their parent star would be too bright.
• Yet once scientists began to study exoplanets as they passed behind their star, they realized that the resulting change in stellar brightness could provide clues to what the atmospheres are made of.
• Astronomers are now using these advanced techniques to detect atoms and molecules of exoplanetary atmospheres. They hope to soon extend their search to molecules that will provide evidence of distant life.

Nobody who was there at the time, from the most seasoned astrophysicist to the most inexperienced science reporter, is likely to forget a press co n ference at the American Astronomical Society's winter meeting in San Antonio, Texas, in January 1996. It was there that Geoffrey W. Marcy, an observer then at San Francisco State University, announced that he and his observing partner, R. Paul Butler, then at the University of California, Berkeley, had discovered the second and third planets ever found orbiting a sunlike star. The first such planet, 51 Pegasi b, had been announced by Michel Mayor and Didier Queloz of the University of Geneva a few months earlier?but a single detection could have been a fluke or even a mistake. Now Marcy was able to say confidently that it had been neither. ?Planets,? he told the crowd, ?aren't rare after all.?

The announcement shook the world of astronomy. Almost nobody had been looking for planets because scientists were convinced they would be too hard to find. Now, after searching a mere handful of stars, astronomers had discovered three worlds, suggesting billions more waiting to be found.

This article was originally published with the title The Dawn of Distant Skies.

Source: http://www.scientificamerican.com/article.cfm?id=astronomers-search-for-signs-life-in-skies-distant-exoplanets

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