The Search For Extraterrestrial Intelligence Many searches have taken place since the OZMA project. In one, carried out by the Ohio State University "Big Ear" antenna, a signal was detected that had all the right characteristics for a signal from ET but, despite many follow up observations, was never observed again. During this time major advances in receiver technology have been made so that now many millions of narrow band frequency channels can be observed simultaneously, widening and greatly improving the efficiency of modern searches. A really large radio telescope is of course a prime requirement; at present the world's largest is the 305-metre Arecibo Telescope in Puerto Rico so it is not surprising that it is being used in the two most sensitive searches being carried out at present, SERENDIP and PHOENIX. More recently, optical searches have also been started. The Search for Extra-Terrestrial Intelligence (SETI) Institute Until 1993, a SETI project was carried out by NASA effort; it was known as the High Resolution Microwave Survey (HRMS). However, after (mostly) political pressure the funding for this programme was terminated. However, a group of scientists and private citizens in the USA decided to set up the SETI Institute, a non-profit corporation that now serves as an institutional home for research and educational projects relating to the study of life in the universe. The SETI Institute conducts research in a number of fields including astronomy and planetary sciences, chemical evolution, the origin of life, biological evolution, and cultural evolution. Its website (http://www.seti-inst.edu/) is a prime source for information about current progress in this wide field.

The Arecibo Telescope, Puerto Rico. Courtesy of the NAIC - Arecibo Observatory, a facility of the NSF, David Parker / Science Photo Library.