To date the only life we know about is here on Earth. Since the beginning of civilization, people have wondered whether there is life elsewhere in the universe. In 1984 American astronomer Jill Tarter and Thomas Pierson launched a project called Search for Extra-Terrestrial Intelligence (SETI), dedicated to that interstellar hunt.
The nonprofit institute was designed to pick up radio signals from space. Radio signals can travel long distances because they are less scattered or absorbed compared to other sorts of radiation, making them more likely to be detected by the 42 radio telescopes that make up the one-of-a-kind Allen Telescope Array in the Cascade Mountains of California. But for 30 years, no verified alien signal has been received.
