Every day, Larry Roark logs on to his 2002 Dell desktop computer in Tampa, Fla., and searches the cosmos for aliens.
A retired insurance salesman, Roark spends hours online poring over pictures of radio waves taken from space, scouting for any unusual ripples or blips that could be Earth's first intergalactic "how-do-you-do."
Since the Adler Planetarium's Search for Extraterrestrial Life website, SETI Live (www.setilive.org), launched earlier this year, an eclectic army of about 56,000 amateur astronomy buffs worldwide have also joined in the hunt from their personal computers.
In Toronto, an IT technician volunteers during his lunch break. In Washington, D.C., an art director hops online at night after putting his two children to bed. In Cordoba, Argentina, a 28-year-old self-described "nerd boy" and "Star Trek" enthusiast has been searching around the clock since he discovered the website last week.
"We don't really know each other," Roark, 61, said. "But we have a common passion, which is looking for E.T."
The website, which lets users sift through black-and-white images of radio signals captured by telescopes, is just the latest in a growing array of online citizen projects helping scientists tackle sophisticated inquiries. Although the goals are diverse, most of the efforts rely on the same principle: Human beings are better than computers at recognizing loose patterns and subtle visual oddities, which might ultimately be key to understanding the natural world, or in the case of SETI, the universe.
"It is really hard to write a computer program that looks for generally interesting stuff," said Chris Lintott, an astrophysicist who helps lead Adler's citizen science program. "Asking, 'Does that look weird?' is a very human question, and that is why we decided that people could be useful."
The SETI Institute has been using telescopes in Hat Creek, Calif., to act as one giant ear, listening to the cosmos. Supercomputers then crunch the radio signals that arrive on 9 billion channels, searching for any bleep, burp or chirp that could be a sign of intelligent alien life.
But the computers aren't good at filtering the "noisier" frequencies. So in 2010, armed with $100,000 from the TED Prize (Technology, Entertainment, Design), Jill Tarter, director of the Center for SETI research at the SETI Institute, and her team reached out to Lintott and his collaborators at the Adler for citizen help.
"Finding a signal of extraterrestrial intelligence would be one of the most profound discoveries mankind has ever made," said Arfon Smith, an astrochemist who directs the citizen science program at the Adler Planetarium.
On Feb. 29, SETI Live was launched. The website displays images of radio signals caught by the Hat Creek telescopes and asks users to identify and discuss any interesting lines, waves or specks that they see. Are they continuous, broken or parallel? Narrow, erratic or wide?
The community grew by tens of thousands, drawn to the site for reasons big and small -- a respite from work, a chance do something online besides Facebook, or the possibility of contributing to one of the biggest scientific breakthroughs in the history of mankind.
Kevin Dorner, an IT technician living in Toronto, now spends his lunch breaks identifying signals and considers himself a permanent part of the "SETIzenry."
"It is something that needs to be done," said Dorner, 43. "I am convinced that something has to be out there."
