This fast radio burst, designated FRB 20240304B, is the most distant ever detected, having traveled more than 10 billion years across the cosmos to reach Earth.
This Webb image shows the host galaxy of FRB 20240304B (shown by the white cross). Image credit: NASA / ESA / CSA / STScI / Themiya Nanayakkara, USYD / Joseph DePasquale, STScI.
Fast radio bursts (FRBs) are among the most mysterious objects in astronomy.
Lasting only milliseconds, these events release enormous amounts of energy but their origins remain uncertain.
Theories range from highly magnetized neutron stars, blasted by gas streams near to a supermassive black hole, to suggestions that the burst properties are consistent with signatures of technology developed by an advanced civilization.
“What makes fast radio bursts interesting is that we don’t know what generates them,” said Dr. Manisha Caleb, an astronomer at the University of Sydney.
“We have theories for what objects produce them, but we don’t have conclusive proof.”
FRB 20240304B was detected on March 4, 2024 by the MeerTRAP project using South Africa’s MeerKAT radio telescope.
The event occurred when the Universe was only about 3 billion years old, more than doubling the previous distance record.
To find its source, the team turned to the NIRCam (Near-Infrared Camera) instrument onboard the NASA/ESA/CSA James Webb Space Telescope.
The host galaxy was invisible to the largest ground-based telescopes, but Webb pinpointed it and measured its distance.
The galaxy turned out to be small, metal-poor and actively forming stars.
This fits the idea that at least some FRBs come from young magnetars, highly magnetized neutron stars born in supernova explosions.
“Our work suggests that it’s very unlikely that this FRB was produced by a merger of two neutron stars,” Dr. Caleb said.
“The next step is to push this frontier further and see how close we can get to the first generations of stars,” said University of Manchester’s Professor Ben Stappers, principal investigator of the MeerTRAP project at the MeerKAT telescope.
“Our results further show the amazing capability of the Webb space telescope where we can push boundaries beyond what was previously possible,” said Dr. Themiya Nanayakkara, an astronomer at the University of Sydney.
The findings appear in the journal Science.
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Manisha Caleb et al. A fast radio burst at redshift 2, three billion years after the Big Bang. Science, published online October 8, 2026; doi: 10.1126/science.adz2675
