World’s Biggest Alien Search Enters Final Stage With 100 Mystery Signals

Astronomers are closing in on the final phase of one of the world's largest searches for extraterrestrial intelligence, as just 100 mysterious radio signals remain under investigation. These are signals that, years ago, were flagged by the global SETI@home project and now are being re-examined using China's powerful FAST radio telescope. But scientists have warned that most, if not all, are probably human-made interference. Nevertheless, each one is being scrutinised very closely for the simple reason that scientists believe any potential, even chance, of discovering alien technologies is worth it.

From Billions of Blips to 100 Signals: How SETI Scientists Narrowed the Search

According to SETI researchers, SETI@home ran from 1999 to 2020 and used millions of computers worldwide to process Arecibo's observations, identifying nearly 12 billion candidate signals. Over time, advanced algorithms and manual inspection reduced this to 100 signals that now deserve careful follow-up.

Since July 2025, FAST has been capturing these signals. As Arecibo fell down in 2020, FAST is the only facility that can make these kinds of observations. Even if no signals turn out to be extraterrestrial, SETI scientists say that the project sets a new sensitivity standard for future searches.

FAST Telescope Takes Over: Tracking SETI Signals and Setting New Standards in Alien Search

The effort highlights the power of citizen science and careful data analysis. Researchers also note that modern computing and machine learning could allow a future review of all SETI@home data, in case signals were missed.

SETI co-founders say the project exceeded expectations, showing global collaboration can advance the search for life beyond Earth.