An artist's rendition of the Kepler space telescope.

NASA’s Kepler Mission to Search for Other “Earths”

March 05, 2009 03:15 PM
by Denis Cummings
NASA’s Kepler satellite will search for evidence of extrasolar Earth-like planets capable of sustaining life.

Kepler Spacecraft Ready for Launch

NASA is set to launch the Kepler probe at 10:48 p.m. EST Friday from Cape Canaveral Air Force Station in Florida. The spacecraft, part of the $600 million Kepler mission, will search the stars in the Milky Way galaxy for signs of Earth-like planets.

The satellite will be propelled into orbit around the sun and spend three and a half years monitoring more than 100,000 stars located in the Cygnus-Lyra region of the Milky Way. A powerful telescope will measure the brightness of the area, searching for drops in brightness—known as transits—that indicate a planet has passed in front of a star.

Since 1995, scientists have discovered more than 300 planets about the size of Jupiter or larger outside our solar system, but such planets are unlikely to contain life. Kepler scientists expect to find hundreds of similar planets, but the true mission is to discover “planets like that of Earth, rocky planets in an orbit where life might be possible,” says William Borucki of NASA’s Ames Research Center.

The Kepler scientists intend to gain an understanding of how many Earth-like planets exist. “Finding that most stars have Earths implies that the conditions that support the development of life could be common throughout our galaxy,” said Borucki. “Finding few or no Earths indicates that we might be alone.”

The search will target planets that take roughly a year to orbit around their sun, indicating that the planet resides in the sun’s “habitable zone,” where “the temperature of the planet was mild enough for liquid water to exist on the surface,” explains’s Andrea Thompson.

It will take several years for scientists to confirm the discovery of an Earth-like planet, as they must detect a planet in its orbit three or four times to be sure that is Earth-like.

You need at least two blips to say, ‘Now I have an orbital period, let's see if there's a third blip at the right time.’ … And if you do that then you're up to a few years of observing time. So my feeling is that by 2013 we'll have some Earths to announce,” Alan Boss, Kepler mission member and author of “The Crowded Universe” told Scientific American.

Qwidget is loading...

Reference: Kepler Web site and astronomy guide


Most Recent Beyond The Headlines