SETI@home's 100 Final Signals Under Scrutiny by China's FAST Telescope
After 25 years of sifting through billions of radio signals, the SETI@home project has narrowed its focus to 100 final candidates—each potentially a whisper from an alien civilization or a mundane burst of Earth-origin interference.
These signals, culled from 12 billion initial detections generated between 1999 and 2020, are now under analysis by China’s FAST radio telescope, the 500-meter aperture instrument succeeding the decommissioned Arecibo observatory.
David Anderson, co-founder of SETI@home, noted that the project’s early years lacked a clear methodology for handling accumulated detections. By 2016, the team had refined its approach, prioritizing signal validation and RFI filtering.
Eric Korpela, a project scientist, emphasized limitations in the 1999-era methods, stating, “We have to do a better job of measuring what we’re excluding.” This transition from citizen science data processing to institutional follow-up reflects evolving technical standards in radio astronomy.
FAST’s role as Arecibo’s successor is critical. Its aperture size allows for higher sensitivity to faint signals, a factor Anderson highlighted in 2025 as essential for distinguishing potential extraterrestrial transmissions from terrestrial noise.
The 100 candidates, initially reduced from 1,000 manually reviewed signals, are being analyzed using methods detailed in 2025 papers published in The Astronomical Journal. These studies focus on data acquisition and signal validation protocols, addressing gaps in earlier methodologies.
The project’s reliance on distributed computing—1.5 million global users contributed processing power during its peak—exceeded initial expectations. However, Korpela acknowledged a “a little disappointment” in the lack of confirmed extraterrestrial signals, contextualizing this within the project’s exploratory nature.
The absence of definitive results underscores the need for continued refinement in signal classification and telescope capabilities.
