Astronomers have confirmed the most distant fast radio burst ever detected, using the James Webb Space Telescope to pin down the galaxy behind a mysterious flash of energy that travelled for more than 10 billion years to reach Earth.

The burst, catalogued as FRB 20240304B, was first spotted on March 4, 2024, by the MeerTRAP project on South Africa’s MeerKAT radio telescope. A study published in the scientific journal Science, led by Manisha Caleb of the University of Sydney, shows the pulse was released when the universe was only around 3 billion years old. It has crossed roughly 80 percent of cosmic history, doubling the previous distance record for any known fast radio burst.

An unexpectedly tiny host galaxy

Initial data suggested the burst came from an extremely distant part of space, but to confirm the distance, astronomers needed to study its host galaxy. They used the James Webb telescope to locate it, and the result surprised the team. Instead of a big, well-formed galaxy full of stars, the flash came from a young, compact dwarf galaxy that is actively forming stars but contains very few heavy elements.

Caleb said the finding was not what anyone had expected. Co-author Ben Stappers of the University of Manchester added that the host galaxy stands out from every other galaxy in their sample. Whatever cosmic mechanism produces these bursts, it clearly operates in young, metal-poor environments.

What could be behind the bursts

Fast radio bursts were first discovered in 2007, and their origins remain one of astronomy’s biggest puzzles — early theories even suggested alien technology. Leading explanations now include the merger of two neutron stars, or a young, highly magnetic neutron star called a magnetar shaking in violent starquakes. None has conclusive proof yet.

Beyond the mystery itself, scientists are excited about what these signals can do as tools. As co-author J Xavier Prochaska of the University of California, Santa Cruz, put it, a fast radio burst is almost like a cosmic flashlight: it lights up everything along its path, carrying the imprint of the matter and structures it passes through. That could let researchers trace the otherwise invisible cosmic web stretching across the universe.