Technosignature

A detectable effect that could indicate technology produced by an extraterrestrial civilization. Examples include artificial radio signals, atmospheric pollutants, and waste heat.

Radio astronomy: The study of celestial objects using radio waves detected by antennas and receivers. Radio telescopes can search for narrowband signals unlike known natural astrophysical emissions.
Search for extraterrestrial intelligence: Scientific efforts to detect signals or other evidence of extraterrestrial intelligence. Technosignature searches form a major observational branch of these efforts.
Astrophysical maser: Natural microwave amplification by stimulated emission in astronomical environments. Maser emission can be narrowband and intense, resembling some proposed artificial radio signals.
Fermi paradox: The apparent tension between the high likelihood of extraterrestrial civilizations and the absence of observed evidence for them. Technosignature searches test one possible response to the question of why no evidence is apparent.
Astrobiology: The interdisciplinary study of life's origin, evolution, distribution, and future in the universe. Technosignatures extend the search for life to evidence of technologically capable organisms.
Atmospheric spectroscopy: The study of a planet's atmosphere by measuring how it absorbs or emits light at different wavelengths. Spectral measurements could reveal industrial gases or other atmospheric changes associated with technology.
Breakthrough Listen: A research program that uses telescopes to search for signals from extraterrestrial civilizations. It conducts extensive radio and optical searches for candidate artificial emissions.
Fast radio burst: A brief, bright burst of radio waves originating outside the Milky Way. Its initially unexplained nature illustrates how natural sources can mimic signs of technology.
Drake equation: A framework for estimating the number of communicative civilizations in the Milky Way. Its uncertain factors affect how likely detectable technosignatures are thought to be.
Contact protocol: Guidelines for responding to a confirmed extraterrestrial signal or evidence of intelligence. A credible detection would raise questions about verification, disclosure, and communication.

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