An Australian radio telescope picked up unusual signals back in 2019 and thinks they originated from Proxima Centauri, a scant 4.3 light years from our blue marble. Researchers caution that it almost certainly is a signal of human or natural origin and that more analysis will probably show it didn’t come from Proxima Centauri. But they can’t yet explain it.
The research is from the Breakthrough Listen project, a decade-long SETI project. The 980 MHz BLC-1 signal, as it’s called, meets the tests that identify the signal as interesting. It has a narrow bandwidth, it drifts in frequency consistent with a signal moving away or towards the Earth, and it disappears when the radio telescope points elsewhere.
The project has been running since 2015 and this was the first signal their algorithms flagged as requiring further analysis. However, the researchers admit the algorithm is intentionally optimistic. After all, you’d rather have false positives to filter out than have any false negatives.
Unfortunately, since the initial set of detections, the team hasn’t found any more signals from the same part of the sky. Proxima Centauri is interesting because it is among our closest neighbors and it is known to have at least two planets, one of which we think could support life.
The 210 foot Parkes radio telescope — better known locally as “the dish” — that detected the signal dates back to 1961 and was the point of reception for the Apollo 11 moon landing. Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) operates the facility and the picture above is courtesy of CSIRO, CC-BY-3.0.