Project Ozma was the first attempt to detect interstellar radio signals from an intelligent extraterrestrial civilization. The American astronomer Frank Donald Drake (1930- ) conducted this pioneering SETI experiment in 1960 at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia. Drake derived the name for his effort from the queen of the imaginary land of Oz since, in his own words, "Oz was a place very far away, difficult to reach, and populated by exotic beings."
He chose a radio frequency of 1,420 megahertz (MHz) for this initial search—the frequency of the 8.3-inch (21-cm) interstellar hydrogen line. Since this is a radio frequency at which most emerging technical civilizations would first use for narrow-bandwidth, high-sensitivity radio telescopes, Drake and other scientists had reasoned that this would also most likely be the frequency that more advanced alien civilizations would probably use in trying to signal emerging civilizations across the interstellar void. This line of thinking gave rise to the popular SETI term water hole.
In 1960, Drake aimed the approximately 85-foot- (26-m-) diameter Green Bank radio telescope at two sunlike stars, Tau Ceti and Epsilon Eridani, which are each about 11 light-years away. Patiently, he and members of his Project Ozma team listened for artifact radio wave signals that
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