Astronomers detect mysterious radio signals from deep space repeating in a cycle of every 157 days

Some scientists believe the signal could be a message from an alien civilization, while others think it could be emerging from neutron stars: which forms after a giant star explodes in a supernova


                            Astronomers detect mysterious radio signals from deep space repeating in a cycle of every 157 days
(Getty Images)

Astronomers have detected a pattern in Fast Radio Bursts (FRB) -- flashes of light that last milliseconds -- repeating every 157 days. And this is only the second such observation so far. The origin of these deep-space signals is still a mystery. Experts detected the first such pattern of radio bursts in January this year. Dr Kaustubh Rajwade of The University of Manchester, who led the new research, said that this is "an exciting result as it is only the second system where we believe we have seen this." 

Pinning down its source of these radio signals is proving to be challenging. However, these observations have given rise to speculations: some believe the signal could be a message from an alien civilization, while others think it could be emerging from neutron stars, which are born when giant stars explode in a supernova. “This exciting discovery highlights how little we know about the origin of FRBs,” says Duncan Lorimer, who serves as Associate Dean for Research at West Virginia University and was involved in the research said. “Further observations of a larger number of FRBs will be needed to obtain a clearer picture of these periodic sources and elucidate their origin,” he added.

A pattern in bursts

Astronomers detected the first First radio Bursts in 2007, and since then, they have identified more than 100 such events. It was in 2016 that scientists realized these signals repeat --albeit sporadically. But, early this year, experts were caught by surprise when they saw a pattern in FRB. It spread it over 16.35 days, with bursts occurring once or twice an hour, for four straight days after which, it went quiet for the next 12 days. Experts used the CHIME telescope in Canada to make this discovery.

Now, they have detected a second such pattern: radio bursts occur for approximately 90 days, followed by a silent period of 67 days, totaling 157 days. The whole pattern then repeats in cycles. "Until now, only one other repeating FRB was known to show such a pattern in its bursting activity," Rajwade told CNN. 

An artist's impression of repeating fast radio bursts (in blue) which is orbiting an object (pink) (Kristi Mickaliger)

Such patterns could help scientists uncover the mysterious origins of FRB. The cyclic behavior could suggest that the object producing these bursts is orbiting another body in the cosmos, Rajwade explained. Given the pattern, the team does not think neutron stars are the likely source of FRB. "Detecting a periodicity provides an important constraint on the origin of the bursts," Rajwade said in a statement. It could argue against a precessing neutron star or the wobble motion of the star's axis. However, this needs more studies.

The team detected the pattern using the Lovell Telescope at the Jodrell Bank Observatory in the United Kingdom for four years.  The telescope, which is 76 meters wide, is specialized to detect sensitive to faint radio signals. In the coming months, the team plans to look for more such patterns to pin down the origins. "Answering these questions will take us closer to the true source of FRBs," he added.

The study was published in the journal Monthly Notices of the Royal Astronomical Society.

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