SETI & Technosignatures Archives

The Milky Way appears above Earth’s bright atmospheric glow in this Aug. 23, 2025, photograph from the International Space Station as it soared 261 miles above southern Iran at approximately 12:54 a.m. local time. The camera was configured for low light and long duration settings. -- NASA/ESA larger image

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

Broadband SETI: A New Strategy To Find Nearby Alien Civilizations

by Keith CowingMarch 10, 2026March 10, 2026

One of the most interesting questions that astronomy can hope to answer is: are we alone in our Milky Way galaxy?

Left panel: schematic of an extraterrestrial transmitter on a planet (green) within the Exo-IPM, with Rimp indicating the impact distance of the passing line of sight between Earth and the ETI transmitter from the stellar object (orange). Right panel: simplified thin-screen representation of phase perturbations in a narrowband monochromatic wave propagating through a turbulent medium, showing Doppler-shifted frequencies. Temporal variations in these perturbations lead to spectral broadening of the transmitted signal. -- The Astrophysical Journal

Astronomy & Telescopes, Biosignatures & Paleobiology, Press Release, SETI & Technosignatures, Space Weather & Heliophysics

Why SETI Might Have Been Missing Alien Signals

by Keith CowingMarch 5, 2026March 5, 2026

A new study by researchers at the SETI Institute suggests stellar “space weather” could make radio signals from extraterrestrial intelligence harder to detect. Stellar activity and plasma turbulence near a […]

Reflecting disc of radius R at distance r from a body of mass M and luminosity L. -- astro-ph.SR

Biosignatures & Paleobiology, Intelligence & Language, Interstellar, SETI & Technosignatures, Status Report

Stellar Engines And Dyson Bubbles Can Be Stable

by Keith CowingMarch 4, 2026March 4, 2026

A range of speculative space ventures envisage the use of ultra-large structures for the collection and reflection of light.

Reconstructed distribution of radio sources on Earth with noise (SNR of 5)

Astronomy & Telescopes, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Intelligence & Language, Interstellar, SETI & Technosignatures, Status Report

Rotational Doppler Cartography Of Technosignatures On Unresolved Planets

by Keith CowingMarch 3, 2026March 3, 2026

The discovery of many Earth-like planets has renewed interest in whether life and technological civilizations exist elsewhere.

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, Status Report

Constraining the Lifespan of Intelligent Technological Civilization in the Galaxy

by Keith CowingFebruary 27, 2026February 27, 2026

In this work, we explore constraints on the emergence and longevity of technologically intelligent civilizations in our Galaxy, considering the Fermi paradox.

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, Status Report

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

by Keith CowingFebruary 27, 2026February 27, 2026

In the search for extraterrestrial intelligence (SETI), it is often assumed that intelligent life on an Earth-like exoplanet would inevitably develop the technological means for interstellar communication. This assumption ignores […]

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, Status Report

Undetected Past Contacts With Technological Species: Implications For Technosignature Science

by Keith CowingFebruary 23, 2026February 23, 2026

In the search for extraterrestrial intelligence (SETI), the highly incomplete sampling of the technosignature search space is often considered as a plausible explanation for the persistent lack of detections over […]

Astrobiology (general), Intelligence & Language, Press Release, SETI & Technosignatures, Societal Issues

Astrobiology On Steroids

by Keith CowingFebruary 19, 2026February 19, 2026

Well … it would seem that NASA will be paying more attention to Astrobiology now.

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, Press Release, SETI & Technosignatures, Societal Issues

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

by Keith CowingFebruary 17, 2026February 17, 2026

Since the first SETI experiment in 1960, astronomers have scanned the Milky Way for signs of advanced extraterrestrial civilizations. These searches have covered radio waves, optical flashes, and infrared heat […]

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, Status Report, 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

K2-18b, a sub-Neptune exoplanet located in the habitable zone of its host star, has emerged as an important target for atmospheric characterization and assessments of potential habitability.