Mysterious repeating energy bursts from space that some experts have suggested could be evidence of advanced alien civilisation for the second time. The bursts, which originate from a distant galaxy that's 1.5 billion light years away from Earth, repeated 13 times, a new study reports.
The discovery of the extragalactic signal is among the first, eagerly awaited results from the Canadian Hydrogen Intensity Mapping Experiment (CHIME). The repeating FRB was one of a total of 13 bursts detected over a period of just three weeks during the summer of 2018, while CHIME was in its pre-commissioning phase.
Over 60 single bursts have been detected previously, but this is only the second time scientists have seen repeated ones. "Knowing that there is another suggests that there could be more out there," said Ingrid Stairs, an astrophysicist from the University of British Columbia (UBC).
The uniquely shaped CHIME telescope in British Columbia.
The source of these super distant signals, from some 1.5 billion light years away, is still largely a mystery. What's agreed upon is that for these radio waves to travel millions of light years and arrive at Earth as strong signals, they must have a profoundly potent origin — perhaps a powerful explosion in another galaxy.
According to National Geographic, each radio burst lasts just thousandths of a second, and they all appear to be coming from far outside our home galaxy, the Milky Way. There are a number of theories about what could be causing them.They include exploding stars, stars with strong magnetic fields, stars merging together and - among a minority of observers - some form of alien mega-structure or beacon.
The majority of the 13 FRBs detected showed signs of "scattering," a phenomenon that reveals information about the environment surrounding a source of radio waves. The amount of scattering observed by the CHIME team led them to conclude that the sources of FRBs are powerful astrophysical objects more likely to be in locations with special characteristics.
"That could mean in some sort of dense clump like a supernova remnant," says team member Cherry Ng, an astronomer at the University of Toronto. "Or near the central black hole in a galaxy. But it has to be in some special place to give us all the scattering that we see."
A leading theory for the source of FRB's is that the leftover cores of exploded massive stars, known as neutron stars, may be releasing the short, powerful signals.
When some old, massive stars collapse, they're believed to squish down into a mass the size of a city, forming a neutron star. Consequently, neutron stars are believed to be the densest known objects in the universe. And presumably, they can release a lot of energy.
One type of neutron star, called a magnetar, is suspected to have a magnetic field trillions of times stronger than Earth's. So when that ultra-dense object changes or ruptures, an extraordinary amount of energy might be unleashed into space.
Astronomers and astrophysicists are eager for the new telescope, CHIME, to pick up more signals and gather more evidence. Or as Tendulkar put it, to "paint a broader picture" of what might be happening out there, in the depths of intergalactic space.
Source:
A second source of repeating fast radio bursts. Nature, 2019
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