Extra Terrestrial Life

A question has hovered in the minds of people over the eons: Does life exist elsewhere in the universe? I have written before on this subject (“Life Out There,” 11/20/08). It’s an ongoing question that we’ve been unable to answer so far, but now seem to be closing in on. Several exciting initiatives recently have been launched—and some of them are providing tantalizing information.

There are fewer questions whose resolution would have a greater impact on us than: “Are we alone?” Many people have invested lots of energy into a belief system that the Earth is unique in the entire universe, and thus solitary in harboring life—especially intelligent life (whatever that is). Others are convinced that the conditions that fostered life here are common throughout the vast universe and thus life must be common. They argue that, even though Earth’s life-favoring conditions are incredibly rare, there is such an unimaginably large number of stars, that those conditions must have been duplicated many places.

This is similar to the ancient debate over whether the Earth sat at the center of the (then-known) universe. Arguments about our place in the cosmos raged on in those times, until science progressed to the point that the answer was found: we’re far from the center.

Similarly, our understanding is now growing about the possibilities of life elsewhere. In the last few decades we’ve discovered extremely tough species (dubbed “extremophiles”) in places here on Earth where we’d previously doubted any form of life could survive: scalding hot pools in Yellowstone, frigid locations in Antarctica, the sunless depths of the ocean. Simultaneously, NASA’s probes have discovered environmental conditions on other worlds in our solar system—a few moons of Jupiter and Saturn—that are quite similar to those tolerated by Earth’s extremophiles.

The December 2009 issue of National Geographic describes very recent results of astronomical studies that have identified nearly 400 planets orbiting stars other than the sun. Many people have long suspected that there must be planets circling other stars, but the proof has been lacking until now. Now we know: over 300 of the nearest stars have multiple planets! And those that we can detect thus far are just the bigger planets (far larger than Earth). Projects are underway that will soon be able to detect Earth-sized planets in the next few years—and even begin to analyze the contents of their atmospheres (if they have any).

Just as Johannes Kepler finally proved that the sun (not the Earth) is at the center of our local universe 400 years ago, we’re on the threshold of discovering if life on other earths exists—or not. Stay tuned.