‘Earthshine’ Technique May Find Alien Life
March 1, 2012 by UPI - United Press International, Inc.
GARCHING, Germany (UPI) — Signs of life on Earth revealed by sunlight reflected onto the moon by our planet could be a way to spot alien life in the universe, European scientists say.
Astronomers have analyzed this reflected light to look for signs of life, or biosignatures, including specific combinations of gases in Earth’s atmosphere that could only exist in tandem with some form of organic life, SPACE.com reported Wednesday.
“With earthshine observations, what we do is use the moon as a giant mirror,” Michael Sterzik at the European Southern Observatory’s La Silla Paranal Observatory in Chile said. “The sun illuminates the Earth, and that light is reflected onto the moon — but the side of the moon that we usually see as the dark portion.”
Astronomers can study the properties of this reflected “earthshine” to study the Earth as if it were an exoplanet and look for signs of life, a release from ESO headquarters in Germany said Wednesday.
And the technique could be a valuable tool in the search for life on worlds outside our solar system, the researchers said.
“It’s currently being applied to giant exoplanets, not because we expect to find life, but just to inspect the atmospheres,” Sterzik said.
“With giant telescopes and more dedicated instrumentation, the technique may be a pathway toward finding primitive biosignatures on other planets in the future.”