Solar system with six exoplanets, others in habitable zones found by NASA's Kepler
Wednesday, February 2, 2011; 9:51 PM
Scientists with NASA's Kepler mission announced Wednesday that they had identified more than 1,200 likely new planets in the past year - a revolutionary development in the quest to understand what lies beyond our solar system.
This celestial bonanza represents more than a tripling of the number of known distant planets. It also includes a remarkable single system with at least six planets orbiting its sun - the most populated solar system found so far outside our own.
The discovery of a system with so many planets could be a sign that other habitable solar systems may be common, according to an exuberant William Borucki, head of the Kepler mission, the small satellite launched two years ago to survey some far reaches of the Milky Way.
Borucki and others likened the importance of Wednesday's announcement to the discovery of the first planet outside the solar system some 15 years ago.
Among the new and yet-to-be-fully-confirmed planets are 68 near the size of Earth and 54 in what is deemed the temperate, or habitable, zone of their solar systems.
"If Earth-sized planets are common, then it's likely that life is common on the planets around their stars," Borucki said. "This is really our first step in man's exploration of surrounding galaxies in terms of life and the extent of life that might be there."
The scientists made it clear that the planets they were finding were almost certainly not capable of supporting life - even the five Earth-size planets in comfortably habitable zones. It will take another year or more to locate planets orbiting far enough from the kinds of stars believed most likely to support life.
But at NASA headquarters, the Kepler scientists described their results with evident excitement. The announcement coincided with publication of a paper in the journal Nature that reported on the six-planet system, named K-11.
Those planets - called exoplanets because they are outside the Earth's solar system - are believed to be largely gaseous rather than rocky and are too close to their sun to support life as we understand it. But the discovery of a system with so many planets orbiting in a manner similar to those in our own system raised hopes that other habitable solar systems may yet be found.
"This is a remarkable system and a very exciting sign of what else is to come," said Jonathan Fortney, a member of the Kepler science team from the University of California at Santa Cruz.
"Given the information Kepler is sending back, we're not only able to identify the planets, but we can tell a lot about how big they are, how close they are to their suns and to some extent what they're made of," he said.
Of potentially great importance as well, the scientists said that some 170 of the stars found to have an exoplanet turned out to have more than one of them. That also signaled that our solar system, with its eight aligned planets, may be far from unique.