Communication with extraterrestrial intelligence
(CETI) is a branch of the search for extraterrestrial intelligence
that focuses on composing and deciphering messages that could theoretically be understood by another technological civilization. The best-known CETI experiment was the 1974 Arecibo message
composed by Frank Drake
and Carl Sagan
. There is no single organization involved in CETI, such as the SETI Institute
, and the abbreviations CETI and SETI alone should not be taken as referring to any organization.
CETI research has focused on four broad areas: mathematical
languages, pictorial systems such as the Arecibo message, algorithmic communication systems (ACETI) and computational approaches to detecting and deciphering 'natural' language communication.
In the nineteenth century there were many books and articles about the possible inhabitants of other planets. Many people believed that intelligent beings might live on the Moon
, and Venus
; but since travel to other planets was not yet possible, some people suggested ways to signal the extraterrestrials even before radio was discovered.Carl Friedrich Gauss
suggested that a giant triangle and three squares, the Pythagoras
, could be drawn on the Siberian tundra. The outlines of the shapes would have been ten-mile wide strips of pine forest, the interiors could be rye or wheat.Joseph Johann Littrow
proposed using the Sahara as a blackboard. Giant trenches several hundred yards wide could delineate... Read More