Canadian telescope hears mystery radio signal repeating every 16 days

Something — or someone — has its deep-space music on repeat.

A mysterious radio signal from space that was first detected in Canada appears to repeat at regular 16-day intervals, according to a draft research paper from the astronomers who are analyzing it.

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The unusual signal, known as a fast radio burst (FRB), has fascinated astronomers since Canada’s CHIME telescope first detected it in 2018. Scientists have discovered hundreds of seemingly random, one-off FRBs over the last decade, but only a handful of them have been found to repeat.

This particular signal is not only repeating, but some “mechanism” appears to be sending it out at regular intervals, according to a pre-print version of the research paper. The findings have not yet been tested by experts.

The signal starts every 16.35 days, lasts for four days and then falls silent for 12 days before starting up again, according to the paper. The number of bursts within each four-day blast varied each time, according to 409 days’ worth of data compiled by CHIME.

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“Our results suggest a mechanism for periodic modulation … and disfavour models invoking purely sporadic processes,” the study authors say in their abstract.

In other words, the signal is not repeating at random. They say the source might be flickering at regular intervals, or some other factor might be interrupting the signal blasts in a consistent pattern.

If confirmed, the discovery would be another first in the early study of FRBs, which have only been known to science for a relatively short period of time.

It would also shed even more light on this particular FRB, which is known by the less-than-memorable name of FRB 180916.J0158+65.

CHIME researchers announced in January that they had traced that same signal back to a spiral galaxy some 500 million light-years from Earth. It was only the second FRB signal ever to be traced back to its source, and the closest known source point to Earth.

Researchers first detected FRBs in 2007. Each burst typically lasts no longer than a few milliseconds, and it’s still unclear what exactly causes them.

Canada’s CHIME telescope near Penticton, B.C., is specifically designed to listen for such radio signals from space.

The CHIME team hopes their latest findings will shed more light on the mysterious origins of the radio signals that echo through our universe.