GREEN BANK - The first scientific search for intelligent life in the universe began in 1960 at the Green Bank Observatory, in Pocahontas County, with a four-month effort to detect interstellar radio signals from two stars in a relatively nearby constellation.
It continues today, as the observatory's 300-foot Green Bank Telescope serves as a key component of Breakthrough Listen, a 10-year international search targeting the one million stars nearest Earth as well as the centers of the 100 galaxies closest to our Milky Way.
This summer, the Green Bank Observatory is hosting a series of behind-the-scenes tours allowing visitors to explore the Pocahontas County radio astronomy facility's pioneering role in the search for extraterrestrial intelligence (SETI, for short) and learn about the key part it plays in Breakthrough Listen, the world's most comprehensive SETI effort, involving a decade-long, $100 million probe that began in January.
"People have been looking for extraterrestrial intelligence here for a long time," said Sherry McCarty, coordinator of the observatory's public tour program. "We wanted to give the public something to let them celebrate the new search and take notice of our SETI history."
Response to the observatory's new three-hour, $40 SETI Tour, which debuted on May 27 and is offered every-other Friday from June 17 through Oct. 21, has been strong. People have booked tours months in advance, and on some dates, second tours have been added to accommodate overflow demand.
Stops along the tour include the 85-foot radio telescope and control room used by Green Bank astronomer Frank Drake, director of Project Ozma, humanity's first scientific SETI search, 56 years ago.
During Project Ozma, "Dr. Drake started work here at 4 a.m., each day," McCarty said, shortly after unlocking the door to the control room of the 85-foot telescope, one of the stops on the SETI Tour.
"He pumped helium up to the receiver to cool it," she said, and had the telescope operator point the dish at a downward angle so the astronomer could access the instrumentation container on the telescope's focus arm via a self-operated scissor-lift platform. Drake then spent about an hour calibrating the telescope's parametric amplifier before observations could begin.
Drake's four-month scan of the two stars failed to detect a series of uniformly patterned pulses that would indicate an intelligent message, although it did turn up the presence of an experimental military aircraft that produced some short-lived excitement.
"Dr. Drake didn't find anything, but he never gave up looking," McCarty said.
Drake, now 86, spent a career in SETI research and now serves on the leadership board for Breakthrough Listen.
In the control room for the now-decommissioned telescope used in making observations for his Project Ozma, tour participants can open filing cabinets to view operating manuals and observation reports, and equipment drawers to look at spare vacuum tubes, switches and other spare parts. Equipment used to turn the telescope and monitor observational data during Project Ozma and subsequent SETI searches remains in place, much as it was in 1960.
"A lot of people say it's like walking into a movie set," McCarty said.
The year after his trailblazing SETI scan, Drake hosted an informal conference at Green Bank that included three Nobel laureates and Carl Sagan, then a 27-year-old post-doctoral astronomer, to discuss the likelihood of making contact with other intelligent life forms.
A few days before the get-together, Drake sketched an outline in algebraic format as a way of organizing what he thought to be the key pieces of information needed to estimate the number of detectable civilizations that might exist in our galaxy, taking into account things like star and planet formation and the percentage of planets in which life was most likely to be possible.
That outline, which became known as the Drake Equation, has no singular solution, but remains in use by scientists as a tool for examining the factors needed to produce extraterrestrial intelligence.
The lounge at Green Bank in which the 12 conferees met, and where the Drake Equation is displayed on a plaque above a fireplace, is a part of the tour, and the place where participants get the chance to ask questions about SETI research from a participating astronomer.
The tour also includes a visit to the observatory's 140-foot telescope, used by Project Phoenix, a SETI search funded by four Silicon Valley executives, to observe 800 candidate stars over a 240-light-year range, between 1996 and 1998.
The 140-foot scope, which remains operational, was used by the University of California's SERENDIP (Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations) in the 1990s before that search switched to the observatory's 100-meter Green Bank Telescope, where data is generated for SERENDIP's "SETI at Home" program in which amateur analysts process search results using personal computers.
Since 2011, the Green Bank Telescope has been used by UC-Berkeley to observe planets identified by NASA's Kepler space telescope as candidates for possibly supporting life.
The Green Bank Telescope is now one of two massive radio-telescopes used by Breakthrough Listen, the other being the 64-meter Parkes Telescope in Australia. For the next 10 years, 20 percent of the Green Bank Telescope's observation time will be devoted to Breakthrough Listen targets, bringing $2w million a year to the observatory. Those taking part in the SETI tour visit the base of the 485-foot telescope and its 2.3-acre collecting surface.
Breakthrough Listen "should give us a definitive answer about our ability to find extraterrestrial intelligence," McCarty said. "After searching such a large section of the sky for ten years, we will either find something, or we will realize that with the current technology being used, it can't be detected, and we may need a better system.
"It could really bring us to a fork in the road."
"Until now, SETI searches have been ad hoc," said Ron Maddalena, project leader for the Green Bank Telescope's role in the project, who took questions from participants in a recent SETI Tour. "At the end of 10 years we will have some definitive statistics on which to base some intelligent decisions."
Advance reservations and screening are required at least 48 hours prior to tours, which are limited to 20 participants each, for those 12 and older. To protect observations by Green Bank's electronically sensitive radio-telescopes, digital cameras are not allowed on the tours, although film cameras are fine. For reservations, send email to gbt-tours@nrao.edu or call 304-456-2150. For more on the observatory's screening policy, visit public.nrao.edu/screening.
The Green Bank Science Center, which interprets the observatory's role and provides the basics of radio astronomy, is open daily from 8:30 a.m. to 7 p.m., with telescope tours departing hourly from 9 a.m. to 6 p.m.
Reach Rick Steelhammer at rsteelhammer@wvgazettemail.com, 304-348-5169, or follow @rsteelhammer on Twitter.