SETI – Page 2 – My WordPress Site

Constraint on the lifetime 𝐿 = 10𝑛 of intelligent technological civilizations derived from the Fermi paradox. The expected number of coexisting civilizations 𝑁 is shown as a function of the civilization lifetime for different assumptions about the probability 𝑓 that a habitable planet produces a technological civilization. The shaded region corresponds to values for which 𝑁 ≫ 1, which are observationally excluded by the absence of detected extraterrestrial civilizations. The dashed line indicates the boundary 𝑁 = 1 and is shown for reference. -- astro-ph.GA

Biosignatures & Paleobiology, Intelligence & Language, SETI & Technosignatures

Constraining the Lifespan of Intelligent Technological Civilization in the Galaxy

by Keith CowingFebruary 27, 2026February 27, 2026

An 80 foot coal seam at the North Antelope Rochelle opencut coal mine.-- Peabody Energy, Inc. -- Provided by Peabody Energy CC BY 3.

Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Intelligence & Language, SETI & Technosignatures

How Common Are Oxygenic Photosynthesis And Large Coal Deposits On Exoplanets?

by Keith CowingFebruary 27, 2026February 27, 2026

Results assuming undetected contacts with technoemissions over the past 65 years. a: Number n of undetected past contacts required to achieve a present-day detectability of at least 95 %, as a function of the search radius R. The thin black line shows the number of habitable planets Np as a function of R calculated from Np = 1010 R dxrρdisk(r)θ(R − d), where d is the distance from Earth. The grey region marks where n > Np. b: Average emitter longevity versus R for selected n/Np values. c: Upper and lower bounds on the expected number of present-day detections, ⟨k⟩, computed from Equation (15) for detectabilities P = 95%, 99%, and 99.9% . For each P, all possible ⟨k⟩ values lie within the corresponding colored areas. -- astro-ph.EP

Astronomy & Telescopes, Biosignatures & Paleobiology, Intelligence & Language, Interstellar, SETI & Technosignatures

Undetected Past Contacts With Technological Species: Implications For Technosignature Science

by Keith CowingFebruary 23, 2026February 23, 2026

Results assuming undetected contacts with technoemissions over the past 65 yr. (a) Minimum number nmin of undetected past contacts required to achieve a present-day detectability of at least 95%, as a function of the search radius R. The thin black line shows the number of habitable planets Np as a function of R calculated from Np = 1010∫ drρdisk(r)θ(R − d), where d is the distance from Earth. The gray region marks where n > Np. (b) Average emitter longevity vs. R for selected n/Np values. (c) Upper and lower bounds on the expected number of present-day detections, 〈k〉, computed from Equation (15) for detectabilities P = 95 %, 99%, and 99.9%. For each P, all possible 〈k〉 values lie within the corresponding colored areas. -- The Astronomical Journal

Astronomy & Telescopes, Biosignatures & Paleobiology, Intelligence & Language, Interstellar, SETI & Technosignatures, Societal Issues

If Alien Signals Reached Earth, Why Haven’t We Seen Them?

by Keith CowingFebruary 17, 2026February 17, 2026

The observed sources and data collected during the K2-18b observing campaign. (Left) The dates of the observations and the frequencies in which signals were detected. (Right) The location of the 64 coherent beams (gray circles), the position of K2-18 (red star), and the FWHM PB for the MeerKAT telescope at L-band. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Intelligence & Language, SETI & Technosignatures, Water/Hycean Worlds & Oceanography

A Narrowband Technosignature Search Toward The Hycean Candidate K2-18b Using The VLA And MeerKAT

by Keith CowingFebruary 11, 2026February 11, 2026

A notional Dyson sphere - Grok via Astrobiology.com

Astronomy & Telescopes, Biosignatures & Paleobiology, Imaging & Spectroscopy, Intelligence & Language, Interstellar, SETI & Technosignatures

WISE/CatWISE Constraints On Dysonian Waste-Heat Technosignatures In Nearby Galaxies

by Keith CowingJanuary 17, 2026

Tarter Award -- SETI Institute

Astrobiology (general), Astronomy & Telescopes, Biosignatures & Paleobiology, People Of Astrobiology, SETI & Technosignatures

SETI Institute Opens Call For Nominations For The 2026 Tarter Award

by Keith CowingJanuary 15, 2026January 15, 2026

A screenshot of the SETI@home user interface on a desktop computer in 2009. The software ran on millions of home computers worldwide, analyzing radio data from space in search of signals from extraterrestrial civilizations. Robert Sanders/UC Berkeley

Astronomy & Telescopes, Biosignatures & Paleobiology, Citizen Science / Open Science, Intelligence & Language, People Of Astrobiology, SETI & Technosignatures

SETI@Home Enthusiasts Used Home Computers To Search For ET. Scientists Focus On 100 signals They Found

by Keith CowingJanuary 13, 2026January 13, 2026

Dr. Jill Tarter -- Green Sands Prize

Astrobiology (general), Astronomy & Telescopes, Biosignatures & Paleobiology, People Of Astrobiology, SETI & Technosignatures

Jill Tarter Awarded the Prestigious Green Sands Prize for Her Pioneering Work in the Search for Extraterrestrial Intelligence

by Keith CowingJanuary 9, 2026January 9, 2026

Echoes In The Void - Grok via Astrobiology.com

Astrobiology (general), SETI & Technosignatures, Video, Audio, Webcasts, Podcasts

So … I asked A.I. to write a song about searching for life in the universe

by Keith CowingJanuary 6, 2026January 6, 2026