May 12, 2009
New technology finds Earth-like planets
U.S. scientists say they have created an
astro-comb technology that helps astronomers detect Earth-like planets orbiting distant stars.
Researchers at the Harvard-Smithsonian Center for Astrophysics said many extrasolar planets can't be seen directly because the glare of their nearby star is too great.
But although a planet might weigh millions of times less than its star, the star will be moved a tiny amount by the gravity interaction with the planet, the researchers said. That motion causes the star to slightly move toward or away from Earth, depending on the planet's mass and its nearness to the star. And it's that motion that allows astronomers to detect heavier planets.
Currently standard spectroscopy techniques can determine star movements to within a few meters per second caused by heavier planets.
But the Harvard scientists using their new technology say they are able to calculate star velocity shifts of less than 1 meter per second -- allowing identification of lighter, Earth-like planets.
Smithsonian researcher David Phillips says he and his colleagues expect to reach a velocity resolution of 60 centimeters per second and perhaps eventually 1 centimeter per second.
The technology will be presented June 1 in Baltimore during the 2009 Conference on Lasers and Electro Optics/International Quantum Electronics Conference.