New Signs of Life in Space?

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ody has yet found life on a planet beyond Earth, but astronomers at NASA's Jet Propulsion Laboratory have come at least a small step closer. Using the Spitzer Space Telescope, an orbiting observatory that sees in infrared rather than visible light, they've detected the telltale signature of two organic chemicals, acetylene and hydrogen cyanide, in a cloud of gas and dust surrounding a baby star. And in the lab, at least, these chemicals are among the building blocks of amino acids (which are themselves the building blocks of proteins)—and also of at least one of the chemical “letters” that make up DNA.

This isn't the first time organic molecules have been detected in deep space: Astronomers have spotted them in giant clouds of gas that swirl between the stars, in the atmospheres of Jupiter and Saturn, and on the surfaces of comets at the frigid edge of our own solar system. But this is the first time they've been found in the disk-shaped cloud of material whirling around a young star—the sort of cloud that scientists believe had surrounded our own Sun in its infancy, and which later coalesced into planets.

What's especially intriguing in this case is that astronomers have taken the temperature of the gases. They're very warm, at or maybe a bit above the boiling point of water—which means they're relatively close to the parent star that's heating them (it's known as IRS 46, and lies about 375 light-years away, in the constellation Ophiuchus). In fact, they're in or near the so-called habitable zone, the region around any star that's neither too hot nor too cold for the existence of life as we know it.

In IRS 46's case, any life that may arise will emerge far in the future, but at least some of the ingredients seem to be in just the right place. The discovery also means that when astronomers finally find an Earthlike planet—right now, still a daydream, but which may become possible within a decade or so—the chances of finding actual life could be even better than we thought.