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date: 30 November 2022

Technosignatures and Astrobiologylocked

Technosignatures and Astrobiologylocked

  • Jacob Haqq-MisraJacob Haqq-MisraBlue Marble Space Institute of Science


This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Planetary Science. Please check back later for the full article.

Astrobiologists are engaged in the search for signs of extraterrestrial life in all forms, known as biosignatures, as well as specific signs of extraterrestrial technology, known as technosignatures. The search for technosignatures and biosignatures attempts to identify characteristic evidence of life on other planets that could be detected using astronomical methods. The first scientific searches for technosignatures took place in the 1960s and used radio telescopes to examine nearby star systems for evidence of narrow-band transmissions used for communication. The search for extraterrestrial intelligence and for anomalous radio and optical signals that would indicate intentional or unintentional extraterrestrial communication continues. Advances in ground- and space-based spectroscopy have enabled searches for technosignatures in exoplanetary systems, such as atmospheric pollution, city lights, large-scale surface structures, and orbiting satellites. Some technosignature searches also attempt to search for nonterrestrial artifacts within the solar system on planetary bodies or in stable orbits. Researchers use known technology on Earth as a starting point for thinking about what might be plausible and detectable in extraterrestrial systems.

Technology is a relatively recent phenomenon in the history of life on Earth, so the search for technosignatures also employs methods of future projection to explore numerous trajectories for extensions of known technology. The range of possibilities considered by technosignature science can include any known or plausible technology that could be remotely detected and would not violate any known physical laws. Megastructures are examples of theoretical large-scale planetary engineering or astroengineering projects that could be detectable in exoplanetary systems through infrared excesses or gravitational effects. Many other technosignatures are possible, even if they do not draw upon Earth projections, but most astrobiological studies of technosignatures focus on predictions that could be tested with current or near-future missions. The discovery of extraterrestrial technology could be of great significance to humanity, but technosignature searches that yield negative results still provide value by placing qualitative upper limits on the prevalence of certain types of extraterrestrial technology.


  • Astrobiology