SETI: the argument for artefact searches

Abstract

For six decades, SETI has attempted to prove the existence of technologically advanced intelligence by detecting artificially generated electromagnetic signals. While such signals could certainly exist and – given the right circumstances – might be measurable here on Earth, contemporary searches are all compromised by limited sensitivity and a reliance on persistent transmissions. The energy required for any putative transmitters, the possible wish of the senders to be cryptic, and a likely ignorance about Homo sapiens’ existence all lead to the reasonable conclusion that greater attention to artefact searches could hasten the discovery of alien intelligence. We consider both the motivation, the advantages and the disadvantages of this approach. We also enumerate some of the specific artefact strategies that have been proposed and pursued.

Technosignatures: Frameworks for Their Assessment

“…However, another example of technosignatures merits consideration, to wit, the possibility of discovering physical artifacts of extraterrestrial technology within the solar system Bradbury et al 2011;Haqq-Misra & Kopparapu 2012;Lacki 2019;Shostak 2020). This notion was broached by Bracewell (1960) in a well-known publication, after which a handful of searches for artifacts have been conducted in geosynchronous Earth orbits (Villarroel et al 2022a(Villarroel et al , 2022b, at the Earth-Moon Lagrange points (Freitas & Valdes 1980;Valdes & Freitas 1983;Freitas & Valdes 1985), and on the lunar surface (Arkhipov 1995;Lesnikowski et al 2020).…”

Von Neumann probes: rationale, propulsion, interstellar transfer timing

“…Unless humanity is the first space-faring civilization or we are under some form of quarantine, it is reasonable to wonder where such probes might be found in the solar system. Due to dynamic geophysical and meteorological processes, space might be a better place to search than Earth's surface (Shostak, 2020). Benford (2019Benford ( , 2021aBenford ( , 2021b suggests inner-solar-system lurker sites.…”

SETI in 2020

“…Indeed, within two years of Cocconi & Morrison (1959)'s foundational article arguing for radio communication as an ideal technosignature, Dyson (1960), Bracewell (1960), and Schwartz & Townes (1961) all argued for others on various grounds. For a good example, see the discussion of Shostak (2020), who made the case for artifacts over radio transmissions.…”