HAT CREEK, Calif. — On a chilly morning last week, Jill Tarter sat in a makeshift corner office facing the Allen Telescope Array, pondering a set of parallel lines that striped a window in her MacBook.

Dr. Tarter directs the Center for SETI Research — SETI is the search for extraterrestrial intelligence — and the 42 antennas that sit outside her window are once again sampling radio emissions from a patch of sky that offers a window into one of the spiral arms of our galaxy. Shuttered for more than a year by budget problems, the array was turned back on in December to continue its search. Now, the searchers have another reason for optimism.

With new Web-based software called SETILive, an army of independent citizen-scientists are being enlisted to help with the hunt for unusual signals. The software, which can be found at setilive.org, was designed by Zooniverse, a team of programmers and scientists who have created Web-based systems to enable citizen participation in research in fields like astronomy and marine biology. SETILive was switched on late last month.

In two weeks, more than 40,000 volunteers have signed up, and more than one million radio samples have been analyzed. (Another Zooniverse project, Galaxy Zoo, has enabled more than 600,000 amateur astronomers to help with classifying an immense number of deep-sky objects since 2007.)