What Are Fast Radio Bursts? The Mystery Millisecond Signals From Deep Space

A fast radio burst, or FRB, is a brief but extremely powerful flash of radio waves that lasts anywhere from a fraction of a millisecond up to a few seconds, according to the English Wikipedia entry on the phenomenon. In that fraction of a second, a typical burst releases roughly as much energy as the Sun emits over three days, the same source states.

How FRBs were discovered

The first fast radio burst was identified in 2007 by astronomers Duncan Lorimer and David Narkevic, who found it while re-examining archival pulsar survey data recorded in 2001; the event is now known as the Lorimer Burst, per Wikipedia. Real-time detection of a new burst did not happen until January 2015, at the Parkes Observatory in Australia, the same entry says.

Since then, purpose-built radio telescopes have turned FRB-hunting into a routine part of astronomy. Canada's CHIME telescope has been cataloguing hundreds of bursts since 2018, Australia's ASKAP array has helped pinpoint the home galaxies of several one-off bursts, and South Africa's MeerKAT telescope — through its MeerTRAP survey project — has become central to recent discoveries, according to Wikipedia and a NASA account of the Webb telescope's involvement in FRB research.

Why the topic is back in the news

On October 8, 2026, researchers led by Manisha Caleb and Themiya Nanayakkara of the University of Sydney published findings in the journal Science describing FRB 20240304B, the most distant fast radio burst identified to date, according to NASA and a report in The Conversation. MeerKAT's MeerTRAP system first detected the burst on March 4, 2024, and the James Webb Space Telescope was then used to find and study its home galaxy, NASA states.

Webb's NIRCam and NIRSpec instruments placed the burst's host galaxy at a cosmological redshift of 2.148, meaning the signal left its source about 3 billion years after the Big Bang and travelled roughly 10.6 billion years before reaching Earth, according to NASA and The Conversation. That more than doubles the distance of the previous record-holder, phys.org reported.

A surprisingly small home galaxy

What struck the research team was not just the distance but the type of galaxy the burst came from. The Conversation reported that the host galaxy contains only about 10 million times the mass of the Sun — roughly 1,000 times less massive than galaxies that typically host FRBs — and has low levels of heavy elements while actively forming new stars. Co-author Laura Driessen described the galaxy as "surprisingly small, metal-poor and undergoing a very active episode of star formation," according to phys.org.

That combination matters for theories about what causes FRBs in the first place.

What is thought to cause fast radio bursts

Despite nearly two decades of study, astronomers have not settled on a single cause for FRBs, and Wikipedia lists several proposed sources, including magnetars, neutron star mergers, supernovae and processes near black holes. The strongest direct evidence so far links FRBs to magnetars — young neutron stars with extremely powerful magnetic fields — after a burst was traced in April 2020 to the Galactic magnetar SGR 1935+2154, the first time an FRB was connected to a specific known object, per Wikipedia.

The new findings on FRB 20240304B reinforce the magnetar explanation over the neutron-star-merger theory, NASA reports, because mergers of two neutron stars typically take a long time to occur after star formation, while this host galaxy's young age and vigorous star formation fit better with magnetars, which form soon after massive stars explode as supernovae.

Repeating versus one-off bursts

Most FRBs detected so far appear to flash only once, but some sources repeat. Wikipedia notes that FRB 121102, found in 2012, was the first repeating source ever identified, located in a galaxy about three billion light-years away. Another source, FRB 180916, is unusual for pulsing on a measurable schedule — roughly every 16.35 days — making it the only known FRB with a regular period, according to the same entry.

Notable fast radio bursts at a glance

What FRBs can teach astronomers

Beyond their origin, scientists use FRBs as cosmic probes. The Conversation reports that the radio waves from FRB 20240304B passed through about 80% of cosmic history, carrying information about magnetic fields, free electrons and charged matter spread through the largely invisible space between galaxies — material that is otherwise very hard to observe directly.

That is why The Conversation describes the burst as an unusually rich source of information about parts of the universe that are otherwise difficult to study directly, crediting the study's researchers for that assessment.