A blast of radio waves hit Earth after travelling for 8 billion years

Astronomers have spotted the oldest fast radio burst (FRB) ever seen, dating back 8 billion years. Hundreds of these strange blasts of radio waves from space have now been detected on Earth since their discovery in 2007, but this one is also the most energetic ever seen.

“The burst has the energy that the sun produces in 30 years,” says Ryan Shannon at the Swinburne University of Technology in Australia. “That is enough power to microwave a bowl of popcorn about two times the size of the sun.”

Shannon and his colleagues spotted the blast of radiation, named FRB 20220610A, using the Australian Square Kilometre Array Pathfinder radio telescope and found that the FRB was three-and-a-half times as energetic as other detected FRBs.

FRBs are thought to come from highly magnetised neutron stars from distant galaxies and usually last just a fraction of a second. “Most of them are never seen again after they have been first found,” says Shannon.

Looking closer at the point in the sky where the emission came from using the Very Large Telescope in Chile, the researchers found a cluster of galaxies that they think contains the source of the blast.

“That means that the burst has been travelling through space for almost 8 billion years,” says team member Stuart Ryder at Macquarie University, Australia.

The previous record holder travelled for just 5 billion years, so this latest discovery suggests that FRBs have been happening for at least half the age of the universe, which is about 13.7 billion years old.

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Astronomers study FRBs to try to build a better picture of the early universe. When these blasts reach Earth, some waves arrive with slightly longer wavelengths than others, because on the journey from the source galaxy to us, the FRB interacts with the stuff in between – mostly freely floating ionised particles like electrons – slowing some of the waves down and stretching their wavelengths.

Observing this allows astronomers to work out how uniform the matter between galaxies is, says Shannon.