Study looks for Earth-like water worlds

GREENBELT, Md., May 28 (UPI) -- U.S. space agency-sponsored scientists say they have developed a technique for determining whether Earth-like extrasolar worlds have oceans.

"A 'pale blue dot' is the best picture we will get of an Earth-like extrasolar world using even the most advanced telescopes planned for the next couple decades," Nicolas Cowan of the University of Washington said. "So how do we find out if it is capable of supporting life? If we can determine that the planet has oceans of liquid water, it greatly increases the likelihood that it supports life.

The researchers used the high resolution telescope on the National Aeronautics and Space Administration's Deep Impact spacecraft to look at Earth from tens of millions of miles away -- to obtain what they called "an alien point of view" -- and developed a method to indicate the presence of oceans by analyzing how Earth's light changes as the planet rotates. That method can be used to identify extrasolar ocean-bearing Earth-like planets.

The scientists, including Drake Deming of the National Aeronautics and Space Administration's Goddard Space Flight Center in Greenbelt, Md., will report their research in the August issue of the Astrophysical Journal.