What is NASAs new SETI program?
NASA has developed sophisticated new radio receivers and computers to carry out a SETI survey of unprecedented sensitivity. A number of radio telescopes around the world will be employed in the search, including the giant antennas of NASA’s Deep Space Network which normally track distant spacecraft. A key element of the program will be its ability to search more than ten million channels simultaneously over a broad range of frequency and to use computer software that has only become feasible in the last few years to pinpoint a variety of complex signals that would not be readily apparent to the human eye or ear. Among the signals the program will be able to find are those that “drift” in frequency; this is important because we expect that we and the senders are each moving in orbit around a star, and that radio signals would thus tend to shift in frequency due to the Doppler effect (which also causes the familiar drop in pitch of a police siren as it comes toward, passes and then begi
