Far outside our Milky Way galaxy, something is causing repeating short bursts of radio waves to be released into space. Scientists have recorded the second repeating fast radio burst to be discovered, according to a study published Wednesday in the journal Nature.
The finding was also presented at the 233rd meeting of the American Astronomical Society in Seattle.
These radio bursts are only millisecond-long radio flashes, and such rapid bursts themselves aren’t rare in space.
But this is only the second one that has been found to repeat. The mystery about why these bursts happen and where they come from continues, which always spurs believers to think that advanced extraterrestrial civilizations are creating them.
The first one, deemed FRB 121102, was discovered in 2015 by the Arecibo radio telescope, and it was revealed in 2018 that the bursts release an enormous amount of energy.
This new repeating fast radio burst is called FRB 180814.J0422+73 and was recorded six times coming from the same location, 1.5 billion light-years away.
This is one of the very first detections made by the new Canadian Hydrogen Intensity Mapping Experiment, or CHIME. The radio telescope was still in its pre-commissioning phase and operating with only a small amount of its full capacity in the summer of 2018 when it detected this and 12 singular fast radio bursts.
And although this new detection doesn’t solve the biggest mysteries surrounding the radio bursts, the researchers who recorded it believe that other repeating fast radio bursts will be found—which could allow them to figure out where they originate.
“Knowing that there is another suggests that there could be more out there,” said Ingrid Stairs, a member of the CHIME team and an astrophysicist at the University of British Columbia. “And with more repeaters and more sources available for study, we may be able to understand these cosmic puzzles—where they’re from and what causes them.”
One hypothesis is that powerful astrophysical phenomena are causing them. The first repeating fast radio burst was recorded at a frequency of 700 megahertz, but some of the bursts CHIME recorded were as low as 400 megahertz.
“[We now know] the sources can produce low-frequency radio waves and those low-frequency waves can escape their environment, and are not too scattered to be detected by the time they reach the Earth,” Tom Landecker, a CHIME team member from the National Research Council of Canada, said in a statement. “That tells us something about the environments and the sources. We haven’t solved the problem, but it’s several more pieces in the puzzle.”
The low frequency of this new detection could mean that the source of the bursts differ. “Scattering” was detected in the fast radio bursts, which is a phenomenon that helps determine more about the environment surrounding the origin.
The CHIME team believes this scattering is indicative of powerful astrophysical objects at the source of the bursts.
“That could mean [the source is] in some sort of dense clump like a supernova remnant,” team member Cherry Ng, an astronomer at the University of Toronto, said in a statement. “Or near the central black hole in a galaxy. But it has to be in some special place to give us all the scattering that we see.”
And if CHIME was able to make these detections before it was even fully up and running, the researchers are hopeful that the new radio telescope will help them find answers about these mysterious signals.