UC Berkeley signal find

Astronomers hunting for alien technology do not look for little green men. They look for odd radio blips, unusual heat, or laser-like flashes that stand out from nature. (science.nasa.gov) That is the frame for a new Berkeley result: after reanalyzing 21 years of SETI@home data, University of California, Berkeley researchers cut roughly 12 billion detections down to about 1 million candidates and then to 100 signals they say merit follow-up. (news.berkeley.edu) SETI@home ran from 1999 to 2020 and used millions of volunteers’ home computers to sift radio observations from the Arecibo Observatory in Puerto Rico. Berkeley says the project is now in hibernation, but the back-end analysis continued and two papers were accepted by *The Astronomical Journal* in June 2025. (news.berkeley.edu) (setiathome.ssl.berkeley.edu) A “candidate” here does not mean a message from another civilization. David Anderson of Berkeley described the raw detections as momentary blips at a particular frequency from a particular point in the sky, and Eric Korpela said the hard part is rejecting noise and human-made radio interference without throwing away a real beacon. (news.berkeley.edu) Berkeley started reobserving the 100 targets with China’s Five-hundred-meter Aperture Spherical Telescope, or FAST, in July 2025. Anderson told Berkeley News he does not expect the team to find extraterrestrial intelligence in that sample, but he said the search sets a new sensitivity level and exposes flaws in older survey methods. (news.berkeley.edu) The larger argument is about machine triage. NASA and a 2023 California Institute of Technology report both describe technosignature work as a data problem, where algorithms can scan volumes of radio and telescope data too large for humans to inspect one by one. (science.nasa.gov) (kiss.caltech.edu) That same logic has pushed searches beyond radio. NASA lists infrared waste heat from hypothetical Dyson spheres, atmospheric chemicals, and laser pulses as other technosignatures, while recent infrared papers warn that dusty background galaxies can mimic the kind of excess heat a megastructure search is trying to find. (science.nasa.gov) (arxiv.org) The “mega-laser” example circulating alongside the Berkeley discussion points to a natural false alarm, not an alien one. A megamaser is an extremely bright microwave source in a galaxy’s core, often linked to active galactic nuclei, and NASA says some are about 100 million times brighter than masers in galaxies like the Milky Way. (science.nasa.gov 1) (science.nasa.gov 2) Astronomers have used those megamasers to map gas around black holes and to study energetic galaxies, including merger systems. Reviews from the Max Planck Institute for Radio Astronomy say hydroxyl megamasers are found in ultra-luminous infrared galaxies and water megamasers can trace gas in active galactic nuclei at sub-parsec scales. (www3.mpifr-bonn.mpg.de) (nature.com) So the Berkeley result is not “we found aliens.” It is that a volunteer-computing project that ended in 2020 still produced a short list of 100 radio anomalies worth checking again with a bigger telescope, while the wider technosignature field keeps building filters for the many natural and human-made things that can look strange at first glance. (news.berkeley.edu) (science.nasa.gov)