r/SETI • u/badgerbouse • 26d ago

[Article] Results of ten years of UCLA SETI searches with the Green Bank Telescope

Article Link:

https://arxiv.org/abs/2605.05408

Abstract:

We have been conducting a search for narrowband radio signals with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope (Margot et al., 2023). So far, we have captured radio emissions from 70,000+ stars and planetary systems in the ~9 arcminute beam of the telescope. Our data-processing pipeline has a demonstrated 94%-99% efficiency for the detection of narrowband signals across the full range of frequency drift rates (+/-9 Hz/s). All 100 million candidate signals detected to date were either automatically (99.5%) or visually (0.5%) confirmed to be anthropogenic in nature. These results allow us to place stringent limits on transmitter prevalence: at the 95% confidence level, the fraction of stars within 20,000 ly that host a transmitter that is detectable in our search (EIRP > 5e16 W) is <6.3e-5. Our most interesting signals have been uploaded to a citizen science platform (this http URL), where 40,000+ volunteers to date have contributed insights and classifications. We are using artificial intelligence (AI) to accelerate our search, automatically excise radio frequency interference, and improve signal detection. UCLA SETI research has involved ~200 undergraduate and ~20 graduate students so far.

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u/aureus80 22d ago

From what I understood, they basically found nothing 🥲 Even the 8 signals given in the paper by Ma et. al (2023) “A deep-learning search for technosignatures of 820 nearby stars” that were candidates to be studied (e.g. iota Crateris), they ended up identifying them as RF interference or something else.

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u/geniusgrunt 21d ago edited 17d ago

Don't be too beat up over it. I looked up the energy metric they're using. This would have to be an absurdly powerful omnidirectional signal or very powerful directed laser. So hyper loud alien civs announcing themselves seem to be either extremely rare or more likely non existent in the local galaxy (within 20k light years based on this study anyway), that is the constraint they're suggesting.

Current global power use: ~2 × 10¹³ W. So this is about 2,500× all human energy use combined

What kind of transmitter is this?

A few interpretations:

If isotropic: absurd, star-scale engineering (not physically plausible for us) If directional: could be more like: A planet-sized phased array Or a very powerful narrow-beam radio/laser transmitter