Technosignatures (concept).
hypothesisframeworkSETI & Technosignatures
Any measurable property evidencing extraterrestrial technology (radio, optical/laser, megastructures, pollutants, artifacts); NASA's 2018 reframing of SETI.
Technosignature broadened SETI beyond radio to include optical/laser pulses, Dyson-sphere infrared excess, atmospheric industrial pollutants, and physical artifacts. NASA's 2018 Technosignatures Workshop and the resulting report mainstreamed the term; NASA awarded its first SETI-specific grant in three decades in 2020. The concept is the conceptual seam where SETI meets UAP work: Avi Loeb's Galileo Project frames near-Earth artifact hunting as artifact-technosignature science complementary to radio SETI — a bridge many SETI scientists view as unestablished.