National Geographic : 2000 Jan
"We have discovered"-she means scientists in general-"organisms thriving in environ ments harsh to us but essential to them. It broadens your perspective. We all suffer to some extent from 'expertitis' in science. It's good for your soul, and good for your intellect, and good for your work to have your imagina tion stretched, to be open to the possibilities." The most tantalizing possibility is that the universe hums with life and that in the com ing centuries we will find it. An exobiologist's abiding optimism is fired by the knowledge that living things are primarily constructed of hydrogen, nitrogen, carbon, and oxygen-the four most common chemically active elements in the universe. And life is inextricably inter woven with nonlife; not even the sharpest razor can perfectly slice them apart. We also know that a functioning ecosystem does not require sunlight or photosynthesis. In the early 1990s researchers found that the basaltic rock deep beneath Washington State contains an abundance of microbes totally cut off from the photosynthetic world. Even more complex life can adapt to hostile places. When scientists in the deep-sea submersible Alvin went tooling around the mid-ocean ridges, they found hot vents covered with shrimp and mouthless tube worms. What remains unknown is whether life can survive over time in narrow ecological niches on largely barren worlds. Could life survive in aquifers far below the harsh surface of Mars? What could endure the cold, dark environ ment of Europa's hypothesized ocean? Can an alien world have just a little bit of life, or are biospheres an all-or-nothing proposition? The cave at Villa Luz, as remote as it is, does not exist in isolation. It is a small, connected piece of a world that riots with life. A SCIENTISTS STRUGGLE to find a trace of life somewhere else in the universe, there exists for many people a more dramatic situation, one in which extraterrestrial life isn't microbial and slimy but rather intelligent, technological, and lurking in our midst. The believers in these Though the Viking lander found no signs of life on Mars in 1976, the results were not definitive. "You could land Viking on some spots on Earth and find no life," says Jack Farmer, an exobiologist who tries to identify the best places to find remnants of Martian life-where evaporating water left min eral deposits that might have fossils. In Death Valley (left) he and a colleague use a spectrometer to confirm aerial images of mineral deposits. This will help Mars orbiters identify prime landing sites. Meanwhile, a robotic plane is being designed to take spectrometer readings of Martian canyon walls.