Repeated Radio Signals from Space — A Sign of Alien Life?
Two new studies published yesterday in the Nature journal describe mysterious repeating radio signals from far outside the Milky Way Galaxy. The source of the fast radio bursts (FRB) is still unknown. What’s notable is that one of the recorded events has a repetitive signal.
Astronomers are not ruling out aliens, although they think it’s more likely that the reasons include rapidly spinning neutron stars and burping black holes.
The FRBs were first identified by the Canadian Hydrogen Intensity Mapping Experiment, CHIME, the world’s most powerful radio telescope, which consists of four 100 x 20 metre semi-cylinders populated with radio receivers. As the Earth turns, CHIME observes half of the sky each day.
“At the end of the year, we may have found 1,000 bursts,” said Deborah Good of the University of British Columbia, one of 50 scientists from five institutions involved in the research.
While the FRBs appear only for a micro-instant, they can emit as much energy as the sun does in 10,000 years. More than 60 bursts have been observed, but only one has been a repeat event — observed in 2012 at the Arecibo Observatory in Puerto Rico. The event was strikingly similar to the 2018 event.
“FRBs, it seems, are likely generated in dense, turbulent regions of host galaxies,” said Shriharsh Tendulkar of McGill University and a corresponding author for both studies and an astronomer at McGill University.
The reasons behind FRBs are subject of hot debate among astronomers, but it is generally believed that the high-energy convulsions are created in two possible scenarios: either when turbulent gas clouds give rise to stars, or when stellar explosions such as supernovas take place. However, it is the repetition of the bursts that has the astronomers perplexed.
“The fact that the bursts are repeated rules out any cataclysmic models in which the source is destroyed while generating the burst,” Tendulkar said. “An FRB emitted from a merger of two neutron stars, or a neutron star and a black hole, for example, cannot repeat.”
Another finding is that most FRBs spotted to date the wavelengths of a few centimetres, while the ones observed by CHIME had intervals of almost a metre.
Even with the repetition, Tendulkar says that it’s unlikely that intelligent life outside of the Milky Galaxy is the source — although there is a small possibility. “As a scientist I can’t rule it out 100 per cent. But intelligent life is not on the minds of any astronomer as a source of these FRBs.”
In addition to the University of British Columbia and McGill University, the other key participants in the studies were the University of Toronto, the National Research Council of Canada, and the Perimeter Institute.
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