Searches for Technosignatures in Astronomy and Astrophysics

Brief

Submitted to the Astro2020 Decadal Survey with 42 endorsers, this seven-page white paper surveys the full landscape of technosignature search strategies and makes the case for NASA and NSF investment. It draws on Wright, Kanodia & Lubar (2018, AJ 156, 240) to establish that even narrowband radio SETI, the best-funded sub-field, has searched only a tiny fraction of the relevant parameter space. The paper frames technosignatures as a logical extension of biosignature science, notes that technology could in principle manifest at planetary, stellar, or galactic scales, and organizes candidate searches along nine axes of merit ranging from cost and ambiguity to information content and duty cycle. Nine specific search categories are identified as ripe for investment, including radio, pulsed laser, thermal infrared, megastructure transits, and multi-messenger approaches.

Metadata

Category

Search

Venue

Bulletin of the American Astronomical Society

Type

White paper

Year

2019

Authors

Jason T. Wright

arXiv

1907.07831

Access

Open access

Length

293.2 K

Programs

Breakthrough Listen, NASA Technosignatures Workshop, Kepler, JWST, LSST, WFIRST, Astro2020 Decadal Survey

Instruments

Kepler, WISE, IRAS, Spitzer, GALEX, Swift, JWST, LSST, WFIRST, NASA Deep Space Network

Data sources

WISE all-sky catalogs, Kepler photometry, IRAS archival data, Spitzer archival data, GALEX archival data, radial velocity planet search archives

Tags

SETI, technosignature, biosignature, exoplanets, astrobiology, policy

Key points

• Financial support for technosignature searches at NSF and NASA has been 'weak to nonexistent,' but the paper argues recent exoplanet discoveries and instrumentation advances make the 2020–2030 window uniquely compelling.p.2
• The prohibition on NASA SETI funding is cultural, not statutory: no law bars it, and both the 2018 House and Senate NASA authorization bills included language affirming technosignatures are part of NASA's life-search mandate, though neither bill passed.p.3
• In 2019, appropriations language allocating $10M/yr for NASA to partner with private sector and philanthropic organizations on technosignature searches did not survive committee.p.3
• Wright, Kanodia & Lubar (2018) quantified how little SETI searching has actually occurred, consistent with earlier analyses by Tarter (2010) and Gray et al. (2002), even in the relatively well-funded narrowband radio domain.p.4
• Technosignatures may be more detectable than biosignatures because technology can, in principle, scale to planetary, stellar, or galactic scope and tap energy supplies that dwarf any biosphere.p.4
• A nine-axis merit framework governs search strategy selection: technology cost, dollar cost, ancillary benefits, signature duty cycle, ambiguity vs. natural confounders, required civilization technology level, motivation specificity, detection ease, and information content.p.5
• SETI false positives have yielded legitimate astrophysics discoveries; the paper cites pulsars, AGN, and Boyajian's Star (Boyajian et al. 2016, MNRAS 457, 3988) as examples of anomalies surfaced by technosignature searches.p.6
• Nine technosignature search categories are flagged as investment-ready: radio, continuous and pulsed laser, thermal infrared, megastructure transits, data science applications, implications of non-detection, Earth-as-exoplanet observations, multi-messenger SETI, and Solar System SETI.p.6

Verbatim

• “contrary to popular understanding, there is no statutory prohibition against NASA funding SETI work; the reasons for lack of funding are purely cultural”

  p.3

• “despite the high public profile of the field very little actual searching has occurred, even in the better- (but still under-)funded field of narrowband radio SETI work”

  p.4

• “There is also an erroneous perception that searches for technosignatures have been thoroughly pursued, and that technosignatures have been shown not to exist in great numbers.”

  p.4

• “Technosignatures may be more ubiquitous than biosignatures (since technological life can, in principle, spread among the stars on its own volition)”

  p.4

• “technology can, in principle, extend to planetary, stellar, or even galactic scales and exploit far larger energy supplies than a biosphere can”

  p.4

• “Exactly because SETI seeks signals of obviously artificial origin, it must deal with and examine the rare and poorly understood astrophysical phenomena that dominate its false positives (e.g., pulsars, AGN, and even Boyajian's Star, Boyjajian et al. 2016).”

  p.6

Most interesting

• The widely believed 'NASA SETI ban' has no legal basis; both chambers of the 115th Congress actually drafted authorization language affirming technosignatures belong in NASA's science portfolio, the bills simply didn't pass.
• A $10M/yr NASA-philanthropic technosignature partnership was written into 2019 appropriations language but was stripped before final passage, illustrating how close formal federal SETI funding came to revival.
• Wright cites three independent quantitative analyses, Tarter (2010), Gray et al. (2002), and Wright, Kanodia & Lubar (2018), all reaching the same conclusion: the volume of parameter space actually searched by SETI remains negligibly small relative to the full target set.
• Archival NASA mission data have quietly supported SETI for decades: IRAS, WISE, Spitzer, GALEX, Kepler, and Swift have all contributed to waste-heat and artifact searches without dedicated SETI allocations.
• The paper explicitly frames the Dyson-sphere concept (Dyson 1960, Science 131, 1667) as a thermal infrared search target actively pursued with existing all-sky catalogs, not merely a thought experiment.
• The nine-axis merit framework treats 'information content' as a distinct evaluation criterion, noting that thermal waste-heat emission from a Dyson structure carries near-zero information about the civilization producing it, while a narrowband radio signal could be information-rich.