Project Ozma, attempt undertaken in 1960 to detect radio signals generated by hypothetical intelligent beings living near stars other than the Sun. Some 150 hours of intermittent observation during a four-month period detected no recognizable signals. Frank D. Drake, director of the search, named the project for the princess of Oz, an imaginary and marvelous distant place described in tales by the American writer L. Frank Baum.
The search was carried out with the aid of a special receiver attached to a radio telescope 26 m (85 feet) in diameter at the U.S. National Radio Astronomy Observatory at Green Bank, W.Va. The receiver was tuned to wavelengths near 21 cm, which is the wavelength of radiation emitted naturally by interstellar hydrogen; it was thought that this would be familiar, as a kind of universal standard, to anyone attempting interstellar radio communication. The telescope was aimed at two nearby stars (Epsilon Eridani and Tau Ceti, both about 11 light-years from the Earth) that resemble the Sun and seem reasonably likely to have inhabited planets.
A second experiment, called Ozma II, was conducted at the same observatory by Benjamin Zuckerman and Patrick Palmer, who intermittently monitored more than 650 nearby stars for about four years (1973–76).