SETI, the Search for Extraterrestrial Intelligence, is an exploratory science that seeks evidence of life in the universe by looking for some signature of its technology. See SETI (the SETI Institute) for more details.
Are there any technical civilizations out there? Do we have the technology to detect their signals? What would be the most efficient way to decipher their messages? The answers to these questions make the foundation of SETI.
Modern attempts to detect extraterrestrial signals date back half a century, to project Ozma in 1960. Early searches focused on the microwave region of the radio spectrum, where there is minimum interference from natural sources in the Galaxy. From those early beginnings, enormous improvements were achieved in the coverage of radio frequencies and area on the sky, but vast regions of search space remained unexplored. With time, new developments in our own technological capabilities...