Astronomers have discovered the brightest and closest fast radio burst ever observed, shedding new light on one of the Universe’s greatest enigmas.
For over a decade, fast radio bursts (FRBs) have baffled astronomers. These fleeting but immensely powerful flashes of radio energy last just milliseconds yet can briefly outshine entire galaxies.
Now, scientists have captured an FRB unlike any seen before – an ultrabright signal from a nearby galaxy 130 million light-years away.
Nicknamed “RBFLOAT” (Radio Brightest Flash of All Time), this extraordinary event is not only the brightest FRB on record but also one of the closest ever detected.
Its intensity and proximity are giving researchers the clearest view yet into the origins and environments of these mysterious cosmic phenomena.
What are fast radio bursts?
Fast radio bursts are intense radio pulses that appear randomly across the sky, each lasting no more than a blink of an eye.
In that instant, they unleash as much energy as our Sun produces in an entire year. First identified in 2007, FRBs quickly became one of astrophysics’ most puzzling discoveries.
Because they can be seen billions of light-years away, FRBs offer a unique tool for probing the structure of the Universe. Yet, their origins remain uncertain.
Leading theories suggest that magnetars — neutron stars with extreme magnetic fields — may be behind at least some of these bursts.
The brightest burst ever seen
On March 16, 2025, astronomers monitoring the sky with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) witnessed a radio flash so strong it initially seemed too bright to be real.
At first, researchers suspected interference from Earth-based signals. But within hours, confirmation arrived from CHIME’s newly expanded Outrigger system: this was no mistake, but the brightest fast radio burst ever detected.
The source was traced to NGC 4141, a spiral galaxy in the constellation Ursa Major. At just 130 million light-years away, this FRB is a rare cosmic neighbour. Its remarkable clarity offers scientists a once-in-a-generation chance to probe the phenomenon in detail.
How CHIME found it
CHIME, located in British Columbia, is made up of four giant halfpipe-shaped antennas. Originally designed to map cosmic hydrogen, it has become one of the most prolific FRB detectors, logging over 4,000 bursts since 2018.
Until recently, though, CHIME lacked the precision to pinpoint exactly where these bursts originated. That changed with the deployment of CHIME Outriggers – smaller companion telescopes stationed across North America. Acting as a continent-wide observatory, they allow astronomers to triangulate FRB signals with extraordinary accuracy.
This event marks the first major discovery using the fully operational CHIME-Outrigger system, proving its power to not only detect bursts but also map them to their host galaxies and specific regions within.
Where the burst came from
Analysis revealed that the fast radio burst originated at the outer edge of NGC 4141, just beyond a zone of active star formation.
This location is particularly intriguing. Magnetars are thought to form in the hearts of such regions, where massive young stars collapse.
The position of this burst suggests it may have come from a slightly older magnetar that has since migrated outward.
This finding adds weight to the idea that FRBs can occur in a variety of galactic environments, reflecting the diversity of their possible sources.
One-off or part of a pattern?
Another major question about fast radio bursts is whether all of them behave the same way. Most appear only once, while a few are repeaters, flashing sporadically or even rhythmically like a heartbeat.
To test whether RBFLOAT might belong to this rarer category, astronomers combed through six years of CHIME data. No other signals were found from the same location, suggesting that this burst is a one-off – at least for now.
Whether repeaters and non-repeaters represent the same underlying phenomenon or entirely different astrophysical events remains an open question. The discovery of RBFLOAT provides an important new data point in this ongoing debate.
A window into the Universe
Because it is both bright and nearby, RBFLOAT is a goldmine for astronomers. By studying how its radio waves travelled through space, scientists can learn about the intergalactic medium, magnetic fields, and even test models of fundamental physics.
The upgraded CHIME-Outrigger system is expected to localise hundreds of bursts every year. As the catalogue of precisely mapped FRBs grows, researchers hope to untangle whether these spectacular events come from a single type of source or represent a family of distinct cosmic explosions.
The discovery of the brightest fast radio burst to date marks a milestone in our quest to understand these mysterious flashes.
For now, the true source of fast radio bursts remains hidden. But with detections like RBFLOAT, astronomers are closer than ever to unlocking the secrets behind these cosmic fireworks.