The techniques and rationale used in six radio-frequency surveys to detect possible signals from extraterrestrial beings (ETs) are reviewed. Reception attempts have been made by pointing antennas at the stars within 80 light years, toward F, G, K, andd M main sequence stars, and binary star systems with component separation less than one-third or more than three times the radius of the habitable zone around the main star. All of the searches explored narrow bandwidths, with attention given to rapid variability. Stars exhibiting variability were re-examined for longer periods, using the 21 cm bandwidth, which is not used for transmissions on earth. The best spectrum analyzer in operation for ET signal search purposes has a capacity of 200,000 channels. Further studies may be carried out at the 10 micron IR wavelength, which could detect planetary-size construction projects by ET civilizations.
Extraterrestrials - Where are they?
- Pub Date:
- Extraterrestrial Intelligence;
- Extraterrestrial Life;
- Interstellar Communication;
- Radio Astronomy;
- Binary Stars;
- Radio Communication;
- Radio Telescopes;
- Space Sciences (General);
- Extraterrestrial Civilizations