Astronomers discover record-breaking radio signal that took 8 billion years to reach Earth: ‘Mind-blowing’

Eight billion years ago, something happened in a distant galaxy that sent an incredibly powerful blast of radio waves through the universe.

It finally arrived on Earth on June 10 last year and – although it lasted less than a thousandth of a second – a radio telescope in Australia managed to pick up the signal.

This glimpse from the cosmos was a fast radio burst (FRB), a poorly understood phenomenon first discovered in 2007.

Astronomers revealed on Thursday that this particular FRB was more powerful and came from far further away than any previously recorded, having traveled eight billion light-years from when the universe was less than half its current age.

Exactly what causes FRBs has become one of astronomy’s great mysteries. Many theories have been thrown out to explain them – a professor at Harvard University even suggested that they might be signs of alien life.

However, scientists believe that the prime suspects are distant dead stars called magnetars, which are the most magnetic objects in the universe.

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

“The jury is still out” on what causes FRBs

“We were lucky to look at that tiny spot in the sky for the one millisecond after the eight billion years the pulse had traveled to capture it,” said Shannon, co-author of a study describing the finding. in the journal Science.

The FRB easily beat the previous record holder, which was from about five billion light years away, he added.

The pulse was so powerful that – in less than a millisecond – it released as much energy as the sun emits over 30 years.

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

But around a thousand have been discovered so far, and scientists have only been able to figure out where only 50 came from – which is crucial to understanding them.

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

It found that the signal originated from a particularly clumpy galaxy that may have merged with one or two other galaxies, which in turn could have created the bizarre magnetar.

Shannon emphasized that this was just the team’s “best guess.”

FRBs have been detected coming from unexpected places, including from our own Milky Way galaxy, so “the jury is still out” on what causes them, he said.

Aside from trying to unravel the secrets behind FRBs, scientists hope to use them as a tool to shed light on another of the universe’s mysteries.

Last year, scientists detected a “strange and persistent” radio burst from a distant galaxy that sounded like a heartbeat. That signal lasted up to three seconds – about 1,000 times longer than the average, according to a news release.

In 2020, astronomers said they detected an FRB that appeared to send signals that reach Earth in a repeating, 157-day pattern.

Artist’s impression of an orbital modulation model where the FRB progenitor (blue) is in orbit with a companion astrophysical object (pink).

Kristi Mickaliger

Only five percent of the universe is made up of normal matter — what everything you can see is made of — while the rest is thought to be composed of the little-understood dark matter and dark energy.

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

Scientists believe this missing matter is spread out in thin filaments connecting galaxies called the cosmic web, but it’s so diffuse that stream telescopes can’t see it.

This is where fast radio bursts come in.

They are “imprinted with the signature of all the gas they travel through,” Shannon said.

Some FRB wavelengths are slightly slower as they travel through this matter, giving scientists a way to measure it.

This could allow them to work out how much matter is in the cosmic web – and therefore the total weight of the universe.

For the record-breaking FRB, Shannon said the team had noticed signals of “extra materials” that the burst had passed through on its journey through the universe.

But to use this information to get an accurate measurement of the universe’s weight, hundreds more FRBs would likely need to be observed, he added.

With much more advanced radio telescopes expected to go online soon, astronomers hope that will happen relatively quickly.

Liam Connor, an astrophysicist at the California Institute of Technology who is not involved in the research, told AFP that future radio telescopes will find tens of thousands of FRBs, allowing scientists to weigh all the matter “across cosmic epochs.”

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