Astronomers discover the most distant radio burst ever

Eight billion years ago, something happened in a distant galaxy, sending incredibly powerful radio waves into space.

It finally reached Earth on June 10 last year, and although it lasted less than a thousandth of a second, an Australian radio telescope was able to pick up the signal.

This flash of light from space was a fast radio burst (FRB), a little-understood phenomenon first discovered in 2007.

Astronomers said Thursday that this particular FRB is more powerful and came from much further away than anything previously recorded, traveling 8 billion light years from a time when the universe was less than half its current age. revealed what he had done.

The exact cause of FRBs remains one of astronomy’s great mysteries. There was early speculation that they could be radio transmissions sent by some kind of extraterrestrial being, especially since some of the signals were repeated.

But scientists believe the main suspect is a distant, dead star called a magnetar, the most magnetic object in the universe.

Ryan Shannon, an astrophysicist at Australia’s Swinburne University, told AFP it was “remarkable” that the ASKAP radio telescope in Western Australia discovered the radio burst last year.

‘lucky’

“We were lucky to be able to observe a tiny dot in the sky for just one millisecond after the pulse traveled for 8 billion years,” said Shannon, co-author of a research paper describing the discovery in the same journal. ” he said. science.

The Fed easily beat the previous record holder, who was about 5 billion light years away, he added.

This pulse was so powerful that in less than a millisecond it released as much energy as the sun releases in 30 years.

Shannon said there could be hundreds of thousands of FRBs flashing in the sky every day.

But of the roughly 1,000 detected so far, scientists have only been able to figure out where they came from, which is critical to understanding them.

To find out where the latest radio burst, called FRB 20220610A, came from, researchers turned to the Very Large Telescope in Chile.

It turns out that the signal was coming from a particularly clumpy galaxy that may have merged with one or two other galaxies, potentially giving rise to the strange magnetar.

Shannon stressed that this was just the team’s “best hunch.”

FRBs have been detected coming from unexpected places, such as within our own Milky Way galaxy, and “the jury is still out” on their cause, he said.

In addition to trying to uncover the secrets of FRBs, scientists hope to use them as a tool to solve other mysteries of the universe.

What’s the problem?

It is believed that only 5% of the universe is made up of ordinary matter (the stuff we see), with the rest made up of little understood dark matter and dark energy. Masu.

But when astronomers count all the stars and galaxies in the universe, more than half of the 5 percent of normal matter is “missing,” Shannon said.

Scientists think this lost material is spread out in thin filaments connecting galaxies called the cosmic web, but it’s too diffuse to be seen with modern telescopes.

That’s where high-speed wireless bursts come into play.

They are “imprinted with the signature of all the gases that pass through them,” Shannon said.

Some wavelengths in FRBs slow down slightly as they pass through this material, giving scientists a way to measure it.

This may allow us to calculate how much matter is in the cosmic web, and thus the total weight of the universe.

Regarding the FRB’s record-breaking, Shannon said the team noticed a signal of “extra material” that the burst passed through on its journey through space.

But he added that scientists would likely need to observe several hundred more FRBs to use this information to accurately measure the weight of the universe.

More advanced radio telescopes are expected to be operational soon, and astronomers hope that will happen relatively soon.

Liam Connor, an astrophysicist at the California Institute of Technology who was not involved in the study, told AFP that future radio telescopes will discover tens of thousands of FRBs and that scientists expect to see them all “beyond the space age.” He said that it would be possible to compare and examine different substances.