In brief: In what is only the second time in history, astronomers have discovered ultra-brief repeating energy bursts from deep space. While these fast radio bursts (FRBs) are likely the result of black holes or strongly magnetized neutron stars, some say they could be evidence of far-flung alien life.
While there have been more than 60 FRBs identified since they were first discovered by accident in 2007 (in data archived since 2001), only one signal had been observed to be repeating itself. But between July and August last year, scientists at the Canadian Hydrogen Intensity Mapping Experiment (CHIME) detected 13 different FRBs, including six repeating bursts from the same location in a galaxy 1.5 billion light-years away—all while CHIME was still in a "pre-commissioning phase."
"Until now, there was only one known repeating FRB. Knowing that there is another suggests that there could be more out there. And with more repeaters and more sources available for study, we may be able to understand these cosmic puzzles -- where they're from and what causes them," said Ingrid Stairs, from the University of British Columbia.
While most previous FRBs had been recorded at frequencies around 1400MHz, these new bursts were collected at between 800MHz and 400MHz—the lowest frequency CHIME can detect.
It’s theorized these FRBs could be created by strongly magnetized, rapidly spinning neutron stars called magnetars. They also show signs of “scattering,” which suggests the sources could be powerful astrophysical objects in locations with special characteristics, the scientists said.
“That could mean in some sort of dense clump like a supernova remnant or near the central black hole in a galaxy,” said Dr. Cherry Ng, an astronomer at the University of Toronto. “But it has to be in some special place to give us all the scattering that we see.”
Interestingly, astrophysicist Emily Petroff, the first person to identify a FRB in real time, pointed out the similarities between the new “repeater” and the only other one to have been discovered.
But possibly most exciting of all... The repeater found by CHIME shows similar frequency and time structure to the only other repeater. The emission cascades down in frequency over time. Figures from CHIME paper 2 (left) and Hessels et al. 2019 (right) https://t.co/hfWhDl2FyB pic.twitter.com/ecL817SHKH— Emily Petroff (@ebpetroff) January 9, 2019
Some have suggested that these radio waves might not be natural, and could come from advanced alien races. Harvard University Professor Abraham Loeb last year said FRBs could originate from planet-sized transmitters that are used to propel giant spaceships by bouncing radio waves off their huge reflective sheets.
“Fast radio bursts are exceedingly bright given their short duration and origin at great distances, and we haven’t identified a possible natural source with any confidence,” said Loeb. “An artificial origin is worth contemplating and checking.
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