Alien signal. Computer artwork depicting an alien signal reaching planet Earth. The signal is shown as a red line moving around space and accidentally striking Earth. The image highlights the work of the SETI (Search for Extraterrestrial Intelligence) project. This was set up by NASA and involves radio telescopes scanning the sky for signals from extraterrestrial civilisations. A lot of SETI's work is trying to distinguish an intelligent signal from the mass of background radio waves coming from space. NASA support was cancelled due to funding difficulties, yet a portion of the project continues through private funding at the SETI institute.