James Webb Telescope traces radio burst 11 billion light-years away — What can this ancient signal reveal about the early universe?

A signal that travelled across the universe for billions of years has given astronomers a rare look at the distant past. The flash lasted just milliseconds. Yet it carried clues about a galaxy that existed when the universe was only about three billion years old.

Scientists have detected the most distant fast radio burst (FRB) ever recorded. Named FRB 20240304B, the signal comes from a galaxy roughly 11 billion light-years away. The discovery more than doubles the distance of the previous record holder.

How a millisecond flash reached Earth from the early universe

FRB 20240304B was emitted when the universe was roughly three billion years old. Today, the universe is estimated to be about 13.8 billion years old, so the signal began travelling long before Earth and the solar system existed.

Fast radio bursts are difficult to study because they usually last only a few milliseconds. Despite their brief duration, they can release enormous amounts of energy in radio waves. Most are detected as sudden flashes, leaving astronomers with little time to determine exactly where they came from.

Radio waves don't travel through completely empty space. Along the way, they pass through gas and other material between galaxies. That material can leave measurable effects on a signal, allowing researchers to investigate matter that might otherwise be difficult to observe.

Manisha Caleb, co-leader of the research team at the Sydney Institute for Astronomy, said the detection offered a glimpse of the universe when it was only about three billion years old. The radio burst also provided information about the matter it had passed through over billions of years.

What the record-breaking burst could reveal about cosmic evolution

Fast radio bursts remain an active subject of research because astronomers still don't fully understand what produces them. Some have been linked to magnetars, neutron stars with extremely powerful magnetic fields. That connection has helped explain at least some bursts, but it doesn't settle the question of whether every FRB has the same origin.

The new detection adds an unusually distant example to the evidence scientists can examine. Because FRB 20240304B comes from an earlier period in cosmic history, it gives researchers a chance to investigate conditions that cannot be studied as easily through nearby events.

The discovery also shows the value of combining different telescopes. MeerKAT detected the burst, while Webb helped scientists identify the galaxy responsible for it.

This approach could help astronomers study even more distant events. Powerful radio bursts may eventually provide information about galaxies that formed much earlier in the universe's history, perhaps near the time of the first stars.

Scientists still have many questions to answer. They do not yet know exactly how all fast radio bursts form or how often different mechanisms produce them.

But each detection gives them another piece of the puzzle. A flash lasting just milliseconds has already revealed a distant galaxy and offered clues about the matter between galaxies. With better observations, these fleeting signals could become powerful tools for understanding how the universe grew into what we see today.

One detection won't answer all those questions. Scientists will need more bursts with identified host galaxies to build a clearer picture of cosmic evolution.