Millions helped search for aliens, and scientists now list 100 signals

UC Berkeley's SETI@home project ran from 1999 to 2020, using volunteers' home computers to analyze Arecibo radio data and collecting more than 12 billion potential signals; researchers have narrowed the results to 100 radio candidates that merit closer study.

UC Berkeley's SETI@home project has produced a shortlist of 100 radio signals that researchers say merit further investigation. The crowd-sourced effort ran from 1999 to 2020 and asked volunteers to install software that let their home computers analyze data recorded by the Arecibo Observatory. Over the project's run, volunteers and the project software flagged more than 12 billion potential signals. Scientists then spent about ten years analyzing and narrowing that set to the candidates now identified. Known points: - The project ran from 1999 to 2020 and relied on volunteers' home computers to process radio data gathered by the Arecibo dish. - More than 12 billion potential signals were recorded during the project and initially flagged by the distributed network of machines. - The team had expected tens of thousands of volunteers but quickly reached roughly a million participants. - The analysis used discrete Fourier transforms and searches for Doppler drift to identify features in the radio data. - A supercomputer at the Max Planck Institute was used to remove radio-frequency interference and noise, reducing the set to a couple million before further vetting produced 100 candidates. - The results are reported in two papers in The Astronomical Journal, and the project team says a fuller final analysis is still to come. Summary: The 100-signal shortlist is the outcome of a large citizen-science effort combined with years of follow-up analysis. The team emphasizes that the list is a set of candidates for closer study rather than a confirmation of extraterrestrial origin, and notes that the work established a new sensitivity level for such searches. The project published results in two papers in The Astronomical Journal, and the final analysis of the data is still to come.