By Ashley Strickland, CNN
(CNN) — Mysterious fast radio bursts, or millisecond-long bright flashes of radio waves from space, have intrigued astronomers since the first detection of the phenomenon in 2007. The enigmatic signals, known as FRBs, release as much energy in less than the blink of an eye as the sun emits in one day.
Researchers are still trying to unravel what the celestial pulses are, as well as how and where they occur. Specialized telescopes have enabled astronomers to track radio bursts within the Milky Way galaxy as well as up to 8 billion light-years away.
Now, four new studies are providing answers about where the fast radio bursts originate, which could shed light on what causes them — but the locations for two recently described radio bursts are wildly different.
One of the fast radio bursts appears to have come from the chaotic, magnetically active environment near a type of dense neutron star called a magnetar. Meanwhile, the other fast radio burst, which scientists observed pulsating over the course of several months, came from the outskirts of a distant dead, star-starved galaxy.
Researchers utilized a fast radio burst-hunting machine called CHIME, or the Canadian Hydrogen Intensity Mapping Experiment radio telescope, to uncover both bursts. The instrument has enabled the detection of thousands of FRBs since 2020.
The disparate origins of the signals suggest the pulses may come in different flavors and originate in various ways.
“This is a step closer to unravelling a profound cosmic mystery,” said Ryan Mckinven, an author on all four studies, in a statement. “FRBs are ubiquitous, yet their true nature remains largely unknown. Every discovery we make about their origins opens a new window into the dynamics of the universe.”
As scientists pin down more details about the varied origins of fast radio bursts, the closer they come to understanding what produces the pulses in the first place.
A ‘twinkling’ origin story
The telltale quick flash of a fast radio burst named FRB 20221022A captured the attention of an international team of researchers in 2022 when CHIME first detected it. The radio telescope, made up of four large half-pipe-shaped receivers, is located near Penticton, British Columbia.
The burst lasted just 2.5 milliseconds and carried the same brightness of other fast radio bursts. But it was notable because the light released by the burst was highly polarized, meaning that the radio waves largely move along a specific trajectory — in this case, traveling in a way that resembled a smooth S-shaped curve.
The emission pattern of the radio waves suggested the site that emitted the burst was rotating and reminded the research team of magnetars, or highly magnetized rotating neutron stars that release radio waves. Scientists have long theorized neutron stars, ultradense core remnants left behind after massive stars explode, as origins of fast radio bursts.
When the team traced the radio waves, it found the burst originated from a galaxy about 200 million light-years away. The team shared the study results in a report published January 1 in the journal Nature.
But the astronomers wanted to take things a step further by determining the precise location of the radio signal within the galaxy. The findings, published in the same issue of Nature, provide additional support that a neutron star created the fast radio burst.
In an attempt to explain how FRBs are formed, scientists have two competing theories.
“Popular neutron star origin models can effectively be split into two camps: one where the signal forms within the star’s magnetic environment, and another where it happens much farther out, driven by a shock launched from the star,” said Mckinven, lead author of the study that traced FRB 20221022A to a galaxy, and coauthor of the companion study. He is a doctoral researcher in the department of physics at McGill University in Montreal.
To determine which scenario applied to FRB 20221022A, the team looked for scintillation, or the glimmering effect created when the light from a small, bright object, such as a star, filters through a galaxy’s interstellar medium, or gas. The smaller or more distant an object, the more it twinkles, said Dr. Kenzie Nimmo, lead author of the companion study and a Kavli Postdoctoral Fellow at the Massachusetts Institute of Technology.
“We discovered that this FRB exhibits ‘twinkling,’ similar to how stars appear to twinkle in the night sky,” Nimmo said. “Observing this scintillation indicates that the region where the FRB originated must be incredibly small.”
The pattern of the burst’s twinkling suggested it originated close to its source, rather than a larger, more distant region that would belong to a shock wave.
Nimmo’s team pinpointed the explosion responsible for the burst to the magnetosphere, a magnetically active area about 6,213 miles (10,000 kilometers) away from a rotating neutron star. That is less than the distance between New York and Singapore, the researchers said.
Zooming in to this small region around a star from 200 million light-years away is “like being able to measure the width of a DNA helix, which is about 2 nanometers wide, on the surface of the moon,” said Kiyoshi Masui, associate professor of physics at MIT, in a statement. Masui was a coauthor of both Nature studies.
“The FRB must have come from the intensely magnetic environment surrounding a neutron star, one of the most extreme environments in the universe,” Nimmo said.
The finding is the first time astronomers have determined FRBs can be generated in the immediate vicinity of a neutron star — a celestial object with the strongest known magnetic field. Researchers are still trying to figure out how the burst exploded away from the star’s magnetic field, which is filled with dense plasma, or highly charged gas.
“Around these highly magnetic neutron stars, also known as magnetars, atoms can’t exist — they would just get torn apart by the magnetic fields,” Masui said. “The exciting thing here is, we find that the energy stored in those magnetic fields, close to the source, is twisting and reconfiguring such that it can be released as radio waves that we can see halfway across the universe.”
Measuring and analyzing the twinkling of FRBs in the future could be a method astronomers use to better understand FRBs, Nimmo said.
Bing Zhang, a distinguished professor in the department of physics and astronomy at the University of Nevada, Las Vegas, has worked on research that models the origin points of fast radio bursts for years and has seen many observational clues suggesting magnetospheres could be a root cause. Zhang was not involved in any of the new studies.
“However, the scintillation results presented by Nimmo et al. gave a direct constraint on the scale of the emission region … presenting very convincing evidence that the FRB emission comes from the magnetosphere of a magnetar,” Zhang said in an email.
Wen-fai Fong, a member of the CHIME collaboration who was not involved in the two Nature studies, said she believes the research provides “the most robust observational evidence to date demonstrating the emission of an FRB originates close to the neutron star’s surface.”
“However we have learned from that the universe likes to surprise us,” said Fong, an associate professor of physics and astronomy at Northwestern University’s Weinberg College of Arts and Sciences, in an email. “We have found a great diversity in the population, and it could be that each one is its own (unique) snowflake.”
And that multiplicity is exactly what Fong and her collaborators discovered while studying another fast radio burst.
Signs of life from an ancient galaxy
A team of astronomers from the CHIME collaboration, including authors of the two Nature studies, was surprised when a new radio burst, designated FRB 20240209A, flared in February 2024 and proceeded to produce 21 additional pulses through July. The burst is the subject of two complementary studies published Tuesday in The Astrophysical Journal Letters.
Six of those pulses were detected by an outrigger telescope 41 miles (66 kilometers) away from CHIME. Outriggers are smaller versions of CHIME that can help astronomers precisely zero in on one specific location where an FRB originates in the night sky.
The team traced the repeating fast radio burst to the edge of an 11.3 billion-year-old galaxy 2 billion light-years from Earth. Then, the researchers used telescopes at the W. M. Keck and Gemini observatories in Hawaii to uncover more details about the ancient, dead galaxy where no new stars are being formed.
“It seems to be the most massive FRB host galaxy to date,” said Tarraneh Eftekhari, lead author of one of the studies, and a NASA Einstein Fellow at Northwestern University’s Center for Interdisciplinary Exploration and Research in Astrophysics, or CIERA.
“It’s among some of the most massive galaxies out there.”
But following FRB 20240209A back to its source showed the burst originated from the outskirts of the galaxy where hardly any stars exist, about 130,000 light-years from the galactic center.
“Among the FRB population, this FRB is located the furthest from the center of its host galaxy,” said Vishwangi Shah, lead author of the complementary study and a doctoral student of physics at McGill University, in a statement. “This is both surprising and exciting, as FRBs are expected to originate inside galaxies, often in star-forming regions. The location of this FRB so far outside its host galaxy raises questions as to how such energetic events can occur in regions where no new stars are forming.”
Before this revelation, scientists have traced only one FRB to the edge of a galaxy. Described in February 2022, the fast radio burst was found within a cluster of stars, called a globular cluster, on the outskirts of galaxy Messier 81, located 12 million light-years from Earth.
Fong, who is also a member of CIERA, said she believes FRB 20240209A could be a twin of that event, compelling astronomers to rethink where and how fast radio bursts form.
Nearly 100 bursts have been traced back to galaxies, and most were likely caused by magnetars, according to the study authors. Magnetars typically form when gigantic stars explode in a “core collapse” supernova, or when gravity triggers a star to collapse on itself.
But FRB 20240209A may have come from a dense cluster of stars, where it’s possible that magnetars could form due to the merger of two neutron stars, or a dead white dwarf star collapsing in on itself, the researchers said.
The team led by Shah has submitted a proposal to use the James Webb Space Telescope for follow-up observations to see whether there is a cluster of stars near where the FRB originated.
“This discovery tells us that perhaps not all FRBs come from young stars, and that maybe there are multiple ways these signals are produced,” Eftekhari said. “Maybe there’s a subpopulation of these events that are coming from older systems.”
Solving one of the universe’s biggest mysteries
Understanding that fast radio bursts may have diverse origins is just the tip of the iceberg that could help astronomers understand more about what they deem to be one of the most mysterious phenomena in the universe.
“It’s clear that there’s still a lot of exciting discovery space when it comes to FRBs, and that their environments could hold the key to unlocking their secrets,” Eftekhari said.
Upgrades to FRB detection technology and the addition of outrigger telescopes will enable the detection and tracing of even more bursts in the future, which could potentially reveal patterns and help determine whether repeating flashes occur in specific types of galaxies, Eftekhari said.
The new research sheds more light on what causes fast radio bursts and where they occur, Zhang said.
“The ‘how’ question is more difficult and needs a lot more work from theorists to tackle it,” he said.
The-CNN-Wire
™ & © 2025 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.
