Evidence brief / LATEST
SETI Survey Tests Previously Neglected Millimetre and Submillimetre Frequencies
A survey presented at the Royal Astronomical Society’s National Astronomy Meeting examined whether SETI searches should extend beyond the traditionally targeted 1.42–1.66 GHz “water hole” [1]. PhD researcher Louisa Mason used archived Atacama Large Millimeter/submillimeter Array (ALMA) observations and searched two narrow Band 3 frequency ranges for narrowband signals that could indicate technological rather than natural astrophysical origins [1]. Across four observations, the analysis found no technosignature candidates above its detection threshold, but the result does not exclude transmitters elsewhere in the sky or spectrum [1]. The study also used the Besançon Galactic Model to estimate “stellar bycatch,” reporting that a reanalysis of 1,327 observations increased the estimated number of observed stars from about 288,000 using Gaia to more than 6.1 million [1]. The source describes the work as a proof of concept and reports recommendations to broaden both frequency coverage and stellar accounting; it does not establish that extraterrestrial signals exist or that the expanded search strategy will find them [1].
Why it matters
The work suggests that conventional SETI surveys may cover only a small portion of the relevant search space and may underestimate how many stars their observations include [1]. Its null result is methodologically informative but remains limited to four observations, two narrow frequency bands, and the survey’s detection threshold [1].
Source record
This brief summarizes what the linked record establishes. It does not treat an unresolved observation as proof of extraterrestrial origin.