Webb Telescope Locates Most Distant Fast Radio Burst, 11 Billion Light-Years Away

Astronomers have identified the host galaxy of the most distant fast radio burst ever detected, using NASA's James Webb Space Telescope and South Africa's MeerKAT radio telescope. The burst, designated FRB 20240304B, was detected on March 4, 2024, and originated approximately 11 billion light-years away when the universe was only about 3 billion years old—more than double the distance of the previous record holder. The finding, published in Science on October 8, 2026, offers new insights into the nature and origins of these mysterious cosmic phenomena that have puzzled astronomers since their discovery in 2007.

Using the MeerKAT telescope's MeerTRAP project, researchers initially detected the burst's radio signature. The James Webb Space Telescope's Near-Infrared Camera identified the host galaxy, and its Near-Infrared Spectrograph measured the galaxy's redshift at 2.148, confirming the burst originated when the universe was roughly 3 billion years old. The discovery is significant because the host galaxy differs markedly from typical FRB sources: it is approximately 1,000 times less massive than expected, yet exhibits extremely active star formation. Researchers estimate that the majority of the galaxy's stars may have formed within just 30 million years during "cosmic noon," a period when star formation across the universe peaked.

The characteristics of this host galaxy provide evidence favoring one theoretical explanation for FRB origins over another. One leading theory proposes that FRBs originate from magnetars—highly magnetic neutron stars created in supernova explosions—which could produce bursts relatively quickly in young, actively star-forming environments. An alternative theory suggests FRBs result from the merger of two neutron stars, a process expected to take billions of years and therefore occur in older, more evolved galaxies. Manisha Caleb of the University of Sydney, lead author of the study, stated that the findings make a neutron star merger origin "very unlikely" for this particular burst, as the young, metal-poor, star-forming nature of the host galaxy aligns better with the magnetar hypothesis.

Beyond determining the FRB's origin, the discovery demonstrates the scientific value of FRBs as cosmic probes. As these millisecond-long radio bursts travel billions of light-years to Earth, they pass through gas and dust in galaxies and the intergalactic medium, allowing scientists to measure the universe's matter distribution and map unseen matter. The burst's 11-billion-year journey means it has travelled through approximately 80 percent of cosmic history, providing a unique probe of galactic evolution and gas dynamics across billions of years. The study represents a collaboration between institutions including the University of Sydney, University of Manchester, and Swinburne University, and underscores the combined capability of ground-based and space-based observatories in advancing astrophysical understanding.