Biosignatures & Paleobiology

Observational Constraints on the Great Filter

By Keith Cowing
March 1, 2020
Filed under
Observational Constraints on the Great Filter
The number of habitable planet observations required to constrain the Great Filter (with 95% confidence) depends upon the fraction of planets with life (η<sub>life</SUB>) and the fraction of inhabited planets with observable technospheres (η<sub>tech</SUB>). A mission such as LUVOIR may able to constrain the value of η<sub>life</SUB>, but subsequent searches for technosignatures will be required to determine whether the Great Filter is in our past (η<sub>tech</SUB> ≥ η<sub>life</SUB>) or future (η<sub>tech</SUB> < η<sub>life</SUB>)

The search for spectroscopic biosignatures with the next-generation of space telescopes could provide observational constraints on the abundance of exoplanets with signs of life.

An extension of this spectroscopic characterization of exoplanets is the search for observational evidence of technology, known as technosignatures. Current mission concepts that would observe biosignatures from ultraviolet to near-infrared wavelengths could place upper limits on the fraction of planets in the galaxy that host life, although such missions tend to have relatively limited capabilities of constraining the prevalence of technosignatures at mid-infrared wavelengths. Yet search-ing for technosignatures alongside biosignatures would provide important knowledge about the future of our civilization.

If planets with technosignatures are abundant, then we can increase our confidence that the hardest step in planetary evolution–the Great Filter–is probably in our past. But if we find that life is commonplace while technosignatures are absent, then this would in-crease the likelihood that the Great Filter awaits to challenge us in the future.

Jacob Haqq-Misra, Ravi Kumar Kopparapu, Edward Schwieterman
(Submitted on 18 Feb 2020)

Comments: Accepted for publication in Astrobiology
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Popular Physics (physics.pop-ph)
Cite as: arXiv:2002.08776 [astro-ph.EP](or arXiv:2002.08776v1 [astro-ph.EP] for this version)
Submission history
From: Jacob Haqq-Misra
[v1] Tue, 18 Feb 2020 21:37:31 UTC (920 KB)
Astrobiology, Astrochemistry

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