Astronomers have discovered a radio signal from 8 billion years ago, which means it traveled through more than half the age and width of the observable universe to get here. Due to its extensive experience in the universe, this signal could actually help us track "missing" matter.
This signal is named FRB20220610A and belongs to a fast radio burst (FRB). As the name suggests, it's a burst of sharp radio waves that last only a few milliseconds and appear to come from all corners of the sky. Their exact origin remains unclear, but they are most likely a type of highly magnetized neutron star called a magnetar.
Most FRBs detected so far originate from hundreds of millions or billions of light-years away. The closest one is just a few tens of thousands of light-years away - within our own Milky Way galaxy. However, the new detection on June 10, 2022 is the most distant FRB discovered to date. The research team said that a distance of 8 billion light-years is likely close to the limit of what modern technology can accurately locate.
Dr. Stuart Ryder, lead author of the study, said: "Using ASKAP's antenna array, we were able to pinpoint where the burst came from. We then used the European Southern Observatory's (ESO's) Very Large Telescope (VLT) in Chile to search for the source galaxy and found that it was older and more distant than any other FRB source discovered to date, and was likely within a small group of merging galaxies."
The research also shows that fast radio bursts could help astronomers unravel another cosmic mystery: missing matter, the team said. Our best models of the universe suggest that the universe should contain some amount of matter, but when scientists tally up all the galaxies, stars, planets, black holes and everything else, there seems to be a huge gap -- we're missing about 40 percent of our normal matter budget (as opposed to dark matter, which is an entirely different thing).
The leading hypothesis is that all this matter is floating in intergalactic space as extremely diffuse gas. This gas is so thin that it's nearly impossible to detect, but that's where FRBs come in. Astronomers can study the arrival times of different wavelengths of light in these radio signals to infer the density of material they pass through. The longer the journey, the more data it contains, making the new radio signals a treasure trove. Sure enough, the new observations appear to be consistent with the diffuse intergalactic gas hypothesis, providing some of the strongest evidence to date.
"While we still don't know what causes these huge bursts of energy, this paper confirms that fast radio bursts are common events in the universe and we will be able to use them to detect intergalactic material and better understand the structure of the universe," said Associate Professor Ryan Shannon, co-first author of the study.
The research was published in the journal Science.