Mysterious 8-billion-year-old radio signal reaches Earth

Astronomers have discovered a mysterious burst of radio waves that took 8 billion years to reach Earth. The fast radio burst is one of the most distant and energetic ones ever observed in history.

Fast radio bursts are intense, millisecond-long bursts of radio waves of unknown origin, CNN reports. The first such radio burst was detected in 2007, and since then hundreds of such fast cosmic bursts have been discovered emanating from distant points throughout the universe.

The flare, called FRB 20220610A, lasted less than a millisecond, but in that fraction of an instant it released energy equivalent to 30 years of emissions from our sun, according to a study published Thursday in the journal Science.

Many fast radio bursts emit ultra-bright radio waves that last a few milliseconds at most before fading, making fast radio bursts difficult to observe, CNN notes.

Radio telescopes have helped astronomers track these fast cosmic flares, including the ASKAP radio telescope array located in Western Australia. Astronomers used ASKAP to detect a fast radio burst in June 2022 and determine its location of origin.

“Using the ASKAP radio array, we were able to pinpoint where the burst originated,” study co-author Dr. Stuart Ryder, an astronomer at Macquarie University in Australia, said in a statement. “We then used the European Southern Observatory’s Very Large Telescope in Chile to search for the parent galaxy, finding that it is older and farther away than any other fast radio burst source discovered to date, and is likely located within a small group of merging galaxies.” .

The research team traced the outburst to what appears to be a group of two or three galaxies that are in the process of merging, interacting and forming new stars. The discovery is consistent with current theories that suggest fast radio bursts could come from magnetars, or high-energy objects produced by stellar explosions, CNN notes.

Scientists believe fast radio bursts may be a unique technique that can be used to “weigh” the universe by measuring the amount of material between galaxies that remains unaccounted for.

“If we count the amount of ordinary matter in the universe—the atoms that make us all up—we find that more than half of what should be there today is missing,” study co-author Ryan Shannon, a professor at Swinburne University of Technology in Australia, said in a statement. . “We think the missing matter is hidden in the space between galaxies, but it may simply be so hot and diffuse that it cannot be seen by conventional methods.”

Until now, the results of modern methods used to estimate the mass of the Universe are inconsistent with each other, which suggests that the entire volume of the Universe is not taken into account.

“Fast radio bursts pick up this ionized material,” says Professor Ryan Shannon. “Even in almost completely empty space, they can ‘see’ all the electrons, and this allows us to measure how much matter is between galaxies.”

This method of using fast radio bursts to detect missing matter was demonstrated by the late Australian astronomer Jean-Pierre Macquart in 2020.

“JP showed that the (further away) a fast radio burst is, the more scattered gas it detects between galaxies,” comments Dr. Ryder. “Some recent fast radio bursts appear to have disrupted this connection.”

About 50 fast radio bursts were traced to their origins, and about half of them were detected using ASKAP, CNN notes.

“Although we still don’t know what causes these massive bursts of energy, the paper confirms that fast radio bursts are common events in space and that we will be able to use them to detect matter between galaxies and better understand the structure of the Universe,” Professor Shannon said.

Astronomers said they hope future radio telescopes currently under construction in South Africa and Australia will detect thousands of faster radio bursts at greater distances.

“The fact that fast radio bursts are so common is also surprising,” says Professor Shannon. “It shows how promising the field can be, because you’re not just going to do this for 30 flares, you can do it for 30,000 flares, make a new map of the structure of the Universe and use it to answer important questions in cosmology.”