SETI in the new millennium

Abstract

SETI, the Search for Extraterrestrial Intelligence, has now been actively pursued for close to 50 years without success. However, this does not imply that we are alone in the Milky Way galaxy for, although most astronomers now agree that intelligent civilizations are far less common than were once thought, we cannot say that there are none. But it does mean that they are likely to be further away from us and, as yet, we have only seriously searched a tiny region of our galaxy. It will not be until the 2020s that an instrument, now on the drawing board, will give us the capability to detect radio signals of realistic power from the whole galaxy. It is also possible that light, rather than radio, might be the communication carrier chosen by an alien race, but optical-SETI searches seeking out pulsed laser signals have only just begun.