LARRY KLAES
Sun, 13 Feb 2005 07:51:33 -0800
The research has proved invaluable. Many of the planets that had been found were "hot Jupiters" - huge, gassy planets so close to their central stars that life seems unlikely. But in recent months, astronomers have improved their instruments to detect smaller worlds. They're finding planets that orbit far enough from their parent stars to make water - thought to be necessary for life - possible. Within a few decades, the researchers say, they may be able to detect the chemical signature of life in the atmosphere of an Earthlike planet Science-fiction writers predicted it decades ago, and now scientists are realizing it's probably true, said Bruce Jakosky, a planetary scientist at CU. "We're recognizing that life on Earth does not appear to be anything special," he said. Here, life took root as soon as it could, almost immediately after meteorites stopped their fiery bombardment of the young planet, Jakosky said. The main message from a decade of planet discoveries is that solar systems dot the Milky Way, circling at least 3 percent of stars. About 200 billion stars are in the galaxy. Researchers could never have predicted the discoveries of the past decade. In early 1995, two teams reported dismal failures in planetary searches. Many scientists began to conclude that our own solar system was alone, a lucky quirk, said Michel Mayor of Switzerland's Geneva Observatory. But then, his team calculated that the faint wobble of a sunlike star had to come from a giant planet spinning quickly around it. Marcy's group confirmed it: The gravitational tug was from a planet half the mass of Jupiter, orbiting its star about every four days. The techniques used to detect such wobbles have been honed since then. Researchers are experimenting with other telescopic techniques. But the next big leap in planet detection - the discovery of other Earthlike planets - probably won't happen until at least 2007, scientists say, when NASA plans to launch the Kepler space telescope. Engineers with Ball are building that instrument now, said Ball's Harold Reitsema. "We're encouraged by all of these discoveries ... to believe that many stars have planets," Reitsema said. NASA and the European Space Agency are also beginning to plan other missions, to launch sometime after Kepler: the Space Interferometry Mission, the Terrestrial Planet Finder and Darwin. But what will happen next isn't clear, although one thing is: There won't be any manned visits to these planets anytime soon, as they probably are tens or thousands of light-years away. Berkley's Marcy ran through a series of calculations suggesting there could easily be thousands of advanced civilizations in the Milky Way. "There's only one problem: Where are they? Why haven't we seen them?" Marcy said. Researchers have found no writing on the moon, no crashed spaceships on Mars, no messages floating through space. Maybe civilizations just don't last long enough to communicate with one another, he suggested. And perhaps Darwinian evolution, generally believed to be an inevitable consequence of life, doesn't inevitably produce intelligence. "Maybe there are other ways to survive and be the fittest," Marcy said. Staff writer Katy Human can be reached at 303-820-1910 or [EMAIL PROTECTED] .
|