Record-breaking radio burst traces back to universe's early star-forming era

A radio signal that lasted roughly one-thousandth of a second has become the most distant fast radio burst (FRB) ever measured, according to a study published in the journal Science in October 2026. Designated FRB 20240304B, the burst traveled for more than 10 billion years before reaching Earth, originating when the universe was approximately 3 billion years old.

What was detected, and how

The burst was first picked up on March 4, 2024, by the MeerTRAP instrument on the MeerKAT radio telescope array in South Africa. Fast radio bursts are brief, intense flashes of radio waves whose physical origin is still debated; thousands have been catalogued, but only a small fraction have had their home galaxies confirmed.

To pin down how far the signal had traveled, researchers led by Manisha Caleb of the University of Sydney turned to NASA's James Webb Space Telescope. Webb's NIRCam instrument located the faint host galaxy, and its NIRSpec instrument measured the galaxy's redshift at 2.148 — the figure astronomers use to calculate cosmic distance and the age of the universe at the time light was emitted. That redshift places the burst's origin about 3 billion years after the Big Bang, during a period often called "cosmic noon," when star formation across the universe was at its peak.

The result more than doubles the distance of the previous FRB distance record, according to phys.org's report on the study.

A galaxy far smaller than expected

The host galaxy itself was the biggest surprise. Caleb and colleagues anticipated a large, well-developed galaxy, similar to many previously identified FRB hosts. Instead, Webb's images and spectra revealed a dwarf galaxy roughly 1,000 times less massive than typical FRB hosts, low in heavy elements, and in the midst of an intense burst of star formation: an estimated 90 percent of its stellar mass had formed within just the preceding 30 million years, per NASA's summary of the findings.

In a separate statement reported by phys.org, Caleb said the burst had been captured from a time when the universe was only about 3 billion years old, adding that researchers used that brief flash of radio light to study the matter it had traveled through over billions of years — underscoring how FRBs can be used as probes of the distant, early universe.

Why the host galaxy matters for FRB theories

Fast radio bursts have no single confirmed source. Leading explanations include magnetars — young neutron stars with extremely strong magnetic fields, typically produced by recent supernovae — and, separately, the eventual merger of two older neutron stars, a process that takes much longer to occur after a galaxy's stars form.

Because the host galaxy of FRB 20240304B is so young and still rapidly forming stars, the research team favors the magnetar explanation for this burst. NASA's account of the study notes that a young, highly magnetized neutron star could form quickly after a nearby supernova in a star-forming galaxy like this one, whereas a neutron-star merger scenario would typically require a longer delay after star formation begins.

What remains uncertain

The study identifies FRB 20240304B as the most distant FRB with a confirmed host-galaxy redshift to date, but researchers caution that a single case cannot settle the broader debate over what causes fast radio bursts. The authors note that the discovery shows little delay is required between a galaxy's star formation and its capacity to produce an FRB, but they stop short of ruling out other progenitor models for different bursts observed elsewhere in the universe.

The research team included Themiya Nanayakkara and Laura Driessen of the University of Sydney and Ben Stappers of the University of Manchester, alongside Caleb, according to NASA and phys.org accounts of the paper.