The question of whether we’re alone in the universe has haunted humankind for thousands of years, and it’s one astronomer Jill Tarter has tried to answer for much of her life. Tarter, chair emeritus of the Center for SETI Research, worked as a project scientist for NASA’s SETI program, which aimed to detect transmissions from alien intelligence. She currently serves on the board for the Allen Telescope Array, a group of more than 350 telescopes north of San Francisco.