The search for alien civilizations is returning to its roots. In the latest chapter of the search for extraterrestrial intelligence, or SETI, researchers are using the Green Bank Telescope in West Virginia to check out some of the distant worlds being discovered in droves by NASA's Kepler spacecraft. Green Bank is where SETI began in earnest more than 50 years ago with a campaign called Project Ozma, led by astronomer Frank Drake.

Some of the Kepler planets appear to orbit at a nice, temperate, potentially life-enabling distance from their host stars, making them especially attractive targets for SETI searches. Most of the Kepler worlds have yet to be confirmed at other observatories, but that has not stopped SETI searchers from scanning them for signs of intelligent life, specifically radio waves.

The most recent West Virginia–based search began May 7 when the 100-meter Green Bank Telescope, the largest steerable radio dish in the world, spent an hour eavesdropping on the field of stars Kepler is observing. According to a University of California, Berkeley, press release, the campaign has been allotted 24 hours of observing time to target 86 of the more than 1,200 planetary candidates Kepler has located.

The researchers, led by U.C. Berkeley graduate student Andrew Siemion, selected the planets in Kepler's catalogue that seem most likely to be hospitable to life as we know it. "We've picked out the planets with nice temperatures—between zero and 100 degrees Celsius—because they are a lot more likely to harbor life," U.C. Berkeley physicist Dan Werthimer said in a prepared statement. Werthimer is chief scientist for the distributed computing project SETI@home, which uses volunteers' idle computing time to sift through data from radio telescopes such as Arecibo in Puerto Rico for possible SETI signals, and which will be enlisted to help process the Green Bank data.

SETI researchers are trying to raise funds for a similar but more sustained Kepler follow-up using the Allen Telescope Array, an interconnected network of smaller radio dishes in northern California. That telescope array went dormant in April when the nonprofit SETI Institute and U.C. Berkeley ran out of money to operate it.

Green Bank Telescope photo courtesy of NRAO/AUI