Scientists detect 8 billion-year-old radio burst. It’s a mystery

Radio telescopes have revolutionized the cosmos.

Radio wave signals from outer space — first detected in 1932 by engineer Karl Jansky — show that the tranquil night sky is not tranquil at all. “The sky looks serene and calm, but if you look in the radio bands, extremely energetic phenomena are taking place in the universe,” Poonam Chandra, an astronomer at the National Radio Astronomy Observatory in Charlottesville, Virginia, previously told Mashable.

Black holes, exploding stars, forming stars, and beyond, shoot out energy in the form of radio waves into the universe.

Yet one type of radio wave detection remains mysterious, though astronomers have leading theories. These signals are called “fast radio bursts,” or FRBs, which are curious pulses of radio waves that last milliseconds, and then vanish. Researchers have now determined the source of the most distant fast radio burst ever detected. It took a whopping 8 billion years to reach Earth.

“In new research published in Science, we have found the most distant fast radio burst ever detected: an 8-billion-year-old pulse that has been travelling for more than half the lifetime of the universe,” Ryan Shannon, an astronomer at Swinburne University of Technology in Australia and an author of the research, wrote online.

The researchers found this fast radio burst, dubbed “FRB 20220610A,” using the sprawling Australian SKA Pathfinder (ASKAP) radio telescope. Astronomers don’t listen to radio waves, but use large satellite dishes, or arrays of many satellite dishes, to collect these signals, often coming from far-off galaxies.

This recent quick burst seemed to come from a great distance away, but to confirm, the team followed up on the location of the FBR with the Very Large Telescope, located in the high Chilean mountains. This observatory contains optical telescopes that see visible light, and astronomers indeed located “faint smudges of light” — evidence of an extremely distant galaxy. This light wave had stretched over time as the universe expanded, and that amount of stretching showed it was a whopping 8 billion years old.

“This confirmed that FRB 20220610A had broken the record for the most distant fast radio burst,” Shannon said.

Revealing the mystery of fast radio bursts

Astronomers will continue to sleuth out and investigate fast radio bursts.

For one, they want to know where these signals, triggered by powerful or explosive activity, originate. There are two leading possibilities, but many more ideas:

• The signals may come from powerful “magnetars,” which are a type of neutron star (the collapsed core of a star). Magnetars are profoundly dense, spin, and have the strongest-known magnetic fields.

• The merging of massive objects in space, like collapsed stars or black holes, might trigger these radio bursts.

(As always, it should be noted that there’s no evidence these fleeting signals come from aliens. After all, it’s never aliens.)

The Very Large Telescope’s view of the distant galaxy that emitted FRB 20220610A. The black circle shows the location of the fast radio burst.
Credit: Lachlan Marnoch (Macquarie Univesity / ASTRO-3D)

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The astronomer Shannon also notes that detecting fast radio bursts can reveal insights about our expansive universe, such as its structure. Great clouds of hot gases float between galaxies, but these fast radio bursts slow when passing through these gases, helping reveal what’s out there in the great cosmos.