A program called SETI (the Search for Extraterrestrial Intelligence) began in 1960, when American astronomer Frank Drake (1930–) spent three months at the National Radio Astronomy Observatory in Green Bank, West Virginia, searching for radio signals coming from the nearby stars Tau Ceti and Epsilon Eridani. Although no signals were detected and scientists interested in SETI have often been ridiculed, support for the idea of seeking out intelligent life in the universe has grown.

Project Sentinel, which used a radio dish at Harvard University’s Oak Ridge Observatory in Massachusetts, could monitor 128,000 channels at a time. This project was upgraded in 1985 to META (Megachannel Extraterrestrial Assay), thanks in part to a donation by filmmaker Steven Spielberg. Project META is capable of receiving 8.4 million channels. NASA began a ten-year search in 1992 using radio telescopes in Arecibo, Puerto Rico, and Barstow, California.

Scientists are searching for radio signals that stand out from the random noises caused by natural objects. Such signals might repeat at regular intervals or contain mathematical sequences. There are millions of radio channels and a lot of sky to be examined. As of October 1995, Project BETA (Billion-channel Extraterrestrial Assay) has been scanning a quarter of a billion channels. This new design improves upon Project META 300-fold, making the challenge of scanning millions of radio channels seem less daunting. SETI has since developed other projects, some “piggybacking” on radio telescopes while engaged in regular uses. A program launched in 1999, SETI@HOME, uses the power of home computers while they are at rest.