After more than a decade of sponsoring SETI searches that listen, the Planetary Society will now turn eyes to the skies to scan for possible light signals with three new optical SETI (the search for extraterrestrial intelligence) programs.
The optical SETI projects are divided between the east and west coasts of the U.S. -- two at the University of California, Berkeley, and one at Harvard University and Smithsonian Observatory in Massachusetts. The Harvard project is led by Physics Professor Paul Horowitz; the University of California projects by Geoff Marcy and Dan Werthimer.
"We have been listening for alien signals for decades; it's time we started to watch for signals as well," said Louis Friedman, Executive Director of the Planetary Society. "These three new optical SETI projects bring the total number of SETI projects sponsored by the Planetary Society to seven -- and brings our historic funding total for SETI to more than$1,000,000."
Werthimer's optical SETI system looks for very short pulses of light from nearby stars similar to the Sun, as well as from a few globular clusters and galaxies. Using Berkeley's 30-inch (76-centimeter) automated telescope at Leuschner Observatory, the project searches for light pulses that may last as short as one billionth of a second.
Marcy's project searches for steady, extremely narrowband or single-color light signals. Marcy will use data from his extensive extrasolar planet searches, data from the Lick and Keck observatories, as well as data from an Australian search.
Horowitz, with colleagues Jonathan Wolff, Chip Coldwell and Costas Papaliolios, has built an improved system inspired by Werthimer's design. Their detector is attached to a 61-inch (1.5-meter) optical telescope next to the Planetary Society-sponsored BETA radio telescope in Harvard, Massachusetts. The optical telescope taps into the light being studied by astronomers David Latham and Robert Stefanik, who are currently measuring the speed of 2,500 nearby sun-like stars, and who are co-investigators in the optical search. The experiment's photometer can detect pulses as short as a few billionths of a second.
Searching for narrowband laser pulse SETI signals was first suggested by Nobel prize winner Charles Townes of the University of California, Berkeley. Dr. Townes is a co-investigator with Marcy and Werthimer. Stuart Kingsley of Columbus, Ohio performed early optical SETI observations. The current projects, with their advanced detectors, were recommended in a study conducted by the SETI Institute, which is also helping to sponsor the searches.