Closeup front view of one antenna of the Allen Telescope Array. (Photo by Colby Gutierrez-Kraybill, through Creative Commons.)
“'Are we alone?' Humans have been asking [this question] forever. The probability of success is difficult to estimate but if we never search the chance of success is zero.” — Jill Tarter
I love the “But if…” part of that quote. It applies to the search for extraterrestrial intelligence (SETI) and it also applies to everything else in life. Dr. Tarter has thrown her heart in the quest for SETI, starting with her work on the SERENDIP project as a graduate student, continuing as a Project Scientist in the NASA SETI program, then on to Director of the SETI Research program for the SETI Institute.
The SETI Institute depends on private funding for its existence. Its primary instrument for looking for alien signals is the Allen Telescope Array (ATA) in Northern California, named for its chief funder, Paul Allen. Instead of using a gigantic dish to scoop up radio waves from space, the ATA uses many smaller dishes and digitally ties them together. This is effectively equivalent to have one extremely large dish. The smaller dishes are inexpensive. It’s also easy to add more dishes as funding permits, thereby increasing the size of the virtual dish. Dr. Tarter’s fundraising focuses on keeping the ATA operational and on track for expansion.
You’re probably wondering what the odds are of finding a signal that originates from a sentient being. There is an equation for that—the Drake Equation. Dr. Tarter does an excellent job explaining in the TEDEd video Calculating the Odds of Intelligent Life.