A flash of radio waves lasting only milliseconds reached Earth after traveling for more than 10 billion years. The MeerKAT telescope in South Africa caught it on March 4, 2024. Astronomers knew roughly where to look, but even powerful ground-based telescopes could not find the galaxy that had sent it.
Now the James Webb Space Telescope has identified that hidden galaxy. A study published in Science on October 8, 2026, establishes FRB 20240304B as the farthest fast radio burst yet traced to its host—and finds an environment that complicates one proposed explanation for these mysterious flashes.
How Webb found the farthest fast radio burst’s home
The MeerTRAP survey, operating with MeerKAT, recorded the burst in 2024 and localized its position. Its radio signal suggested an extraordinary distance, but confirming that required identifying a galaxy and measuring how much its light had been stretched by cosmic expansion.
Webb’s infrared camera, NIRCam, detected a faint object at the right location. Its NIRSpec spectrograph measured a redshift of 2.148, placing the event at a time when the universe was about 3 billion years old. The result more than doubled the previous distance record for a localized fast radio burst, according to Live Science’s report.
The surprise was not just the distance
Researchers expected a substantial, mature star-forming galaxy. Instead, they found a small dwarf galaxy actively making stars, with a mass roughly 1,000 times below their expectation. The team estimates that much of its stellar population may have formed within just 30 million years.
That matters because the engines behind fast radio bursts remain unsettled. Some models invoke mergers of neutron stars, which can take a very long time to occur. Others involve young, intensely magnetic neutron stars called magnetars, which can form soon after a massive star explodes. The young host makes a long-delayed merger less likely for this particular burst and strengthens the magnetar interpretation, but it does not prove what produced the flash. The Max Planck Institute for Radio Astronomy, whose researchers contributed to the study, emphasizes that distinction.
A brief signal that mapped invisible space
The burst also carried information about the ionized material it passed through. Researchers identified imprints associated with a previously unknown galaxy cluster and the nearby Virgo Cluster. As the European Webb team explains, these short flashes can act as probes of otherwise hard-to-see matter between galaxies.
The burst itself is not a newly detected 2026 event: MeerKAT recorded it in 2024, and earlier research circulated before this week’s peer-reviewed publication. What changed is the strength of the evidence about its distant, unexpectedly small home. Future discoveries could test whether young galaxies commonly host such flashes—or whether this record-holder is an exception.
