Astronomers have discovered a ‘radio burst’ coming from a galaxy far, far away

It took eight billion years to reach us: astronomers have detected an incredibly powerful burst of radio waves in a galaxy far, far away. This is a discovery that would help uncover the mystery of this cosmic phenomenon, according to a study published Thursday.

This “fast radio burst” called FRB (fast radio burst), a flash of electromagnetic waves lasting less than a millisecond, finally reached Earth on June 10, 2022, when an Australian telescope was able to pick up its signal.

It came from a galaxy much further away than those recorded by previously recorded fast radio bursts, traveling eight billion light-years, a time when the universe was less than half its current age, astronomers revealed in the journal Science.

Since such signals were first discovered in 2007, scientists have wondered about the exact origin of this cosmic phenomenon, which is difficult to determine because it is subtle.

Because these signals sometimes repeat themselves, some initially assumed that we were dealing with radio communications transmitted through space by an extraterrestrial being.

Even more seriously, scientists believe the prime suspect is an incredibly dense dead star called a magnetar, which has an extremely strong magnetic field.

“It’s amazing” that the ASKAP telescope, located in Western Australia, can detect these fast radio bursts, Ryan Shannon of Australia’s Swinburne University (in Melbourne), co-author of the study, told AFP.

“We were lucky to be able to observe this tiny dot in the sky for a millisecond, eight billion years after the pulse traveled in order to capture it,” the astrophysicist adds.

The radio burst easily beat the previous record, which traveled about five billion light-years. Incredibly powerful, because in less than a millisecond, the pulse released as much energy as the Sun emits in 30 years.

“cosmic web”

According to the scientist, hundreds of thousands of fast radio bursts may occur in the sky every day. But only a thousand have been discovered so far, and researchers have only been able to determine their home galaxy for about fifty of them. However, this is an essential element for understanding this phenomenon.

To determine the source of this distant radio burst, called FRB 20220610A, researchers turned to the Very Large Telescope (VLT) in Chile.

The latter revealed that the signal came from a particularly dense galaxy, which could have merged with one or two other galaxies, giving rise to the strange magnetar.

But this is only scientists’ “best hunch,” asserts Ryan Shannon.

Because the radio bursts have been detected in unexpected places, including within the Milky Way, “the jury is still out” on what causes them, he notes.

Meanwhile, these radio bursts could help clarify another mystery: the amount of solid matter in the universe. It is supposed to represent about 5% of this universe, with the rest consisting of dark matter and dark energy.

the problem ? More than half of this 5% of solid matter is missing. Scientists believe it lies in the cosmic web, thin threads of gas that connect galaxies together, but they are so widespread that they are invisible to telescopes.

Unless you use fast radio bursts, which “carry the imprint of all the gas they passed through,” as the astrophysicist explains. This gas actually changes the wavelength of fast radio bursts, thus making it possible to measure the intensity of the latter.

The fast radio bursts recorded by the Australian telescope bear the signature of “excess matter,” according to the researcher. A large number of radio waves still need to be recorded to improve calculations of missing matter.

In fact, new telescopes dedicated to radio astronomy are expected soon.