Ongoing effort to seek intelligent extraterrestrial life. SETI focuses on receiving and analyzing signals from space, particularly in the radio and visible-light regions of the electromagnetic spectrum, looking for nonrandom patterns likely to have been sent either deliberately or inadvertently by technologically advanced beings. The first modern SETI search was Project Ozma (1960), which made use of a radio telescope in Green Bank, W.Va. SETI approaches include targeted searches, which typically concentrate on groups of nearby sunlike stars, and systematic surveys covering all directions. The value of SETI efforts has been controversial; programs initiated by NASA in the 1970s were terminated by congressional action in 1993. Subsequently, SETI researchers organized privately funded programs—e.g., the targeted-search Project Phoenix in the U.S. and the survey-type SERENDIP projects in the U.S. and Australia. See also Drake equation.

Variants of SETI

SETI in full search for extraterrestrial intelligence

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