Search for extraterrestrial intelligence

The search for extraterrestrial intelligence (usually shortened as SETI) is the diverse efforts and scientific projects intended to detect extraterrestrial signals, or any evidence of intelligent life beyond Earth. Researchers use methods such as monitoring electromagnetic radiation, searching for optical signals, and investigating potential extraterrestrial artifacts for any signs of transmission from civilizations present on other planets.

Source: Wikipedia — Search for extraterrestrial intelligence (CC BY-SA 4.0)