Astronomers Detect the Most Distant Fast Radio Burst Ever—A Cosmic Signal That Traveled for Over 10 Billion Years

Astronomers have detected an extraordinary signal from the distant universe: a powerful flash of radio waves that traveled for more than 10 billion years before reaching Earth. The discovery marks a major milestone in astronomy and could help scientists understand how galaxies evolved and reveal the vast amounts of invisible matter spread throughout the cosmos.

The signal, known as FRB 20240304B, is the most distant fast radio burst (FRB) ever detected and traced to its host galaxy. The discovery more than doubles the previous distance record, opening a new window into a much younger universe.

The research, led by Dr. Manisha Caleb and Dr. Themiya Nanayakkara of the University of Sydney, was published in the scientific journal Science. The team used South Africa's MeerKAT radio telescope to detect the burst and NASA's James Webb Space Telescope (JWST) to identify the distant galaxy from which it originated.

Beyond setting a new record, the discovery demonstrates how brief flashes of radio energy can help astronomers investigate some of the universe's biggest mysteries.

What Are Fast Radio Bursts?

Fast radio bursts are intense flashes of radio waves that usually last only a few milliseconds. Despite their extremely short duration, they can release enormous amounts of energy.

Scientists first discovered FRBs in 2007, and these mysterious signals have since become an important subject of astronomical research. Thousands of bursts have been identified, but their exact origins and the physical processes behind them are still being investigated.

Some FRBs repeat, producing multiple bursts over time, while others have been observed only once. This variety suggests that more than one process could be responsible for these signals.

One leading explanation involves magnetars, which are highly magnetized neutron stars. These compact objects can form when massive stars explode in supernovas. Their powerful magnetic fields and extreme physical conditions may produce the intense radio emissions detected as FRBs.

However, scientists have not yet established a single explanation for every fast radio burst. Studying distant events such as FRB 20240304B could help researchers understand which environments and physical processes produce them.

A Signal From When the Universe Was Young

One of the most remarkable features of FRB 20240304B is its extraordinary distance.

According to the research, the burst originated when the universe was approximately three billion years old. The universe is now about 13.8 billion years old, meaning the signal offers a glimpse into a much earlier period of cosmic history.

Radio waves travel at the speed of light, so observing distant objects allows astronomers to look back in time. The farther away an object is, the longer its light or other electromagnetic radiation takes to reach us.

In this case, the radio signal traveled across more than 10 billion years of cosmic history before arriving at Earth.

"This is an extraordinary glimpse into the distant universe," said Dr. Caleb, highlighting how a brief radio flash can reveal information about the matter it encountered during its journey.

The discovery is particularly important because astronomers have now demonstrated that they can detect and investigate fast radio bursts from a period when the universe was relatively young.

Previously, studying such distant bursts and confidently identifying their origins was much more difficult. This new result shows that researchers can push these observations farther into the past than before.

How MeerKAT and the James Webb Telescope Solved the Mystery

Detecting a fast radio burst is only the beginning. Astronomers must also determine where it came from and identify its host galaxy to understand the environment in which it occurred.

For FRB 20240304B, researchers combined observations from two powerful astronomical facilities.

South Africa's MeerKAT radio telescope, working with the MeerTRAP project, detected the brief radio signal. MeerTRAP is designed to search for fast radio bursts and other short-lived radio events.

However, the galaxy associated with the burst was extremely faint and difficult to observe. Even the largest ground-based telescopes could not identify it clearly.

The team therefore turned to NASA's James Webb Space Telescope, which observes the universe using infrared light. Its exceptional sensitivity allows astronomers to study faint galaxies that formed billions of years ago.

By combining infrared imaging and spectroscopy, researchers identified the host galaxy and measured its distance.

Spectroscopy allows scientists to examine the light from a distant object and determine important properties, including its chemical composition and how rapidly the universe's expansion has stretched its light toward longer wavelengths.

The collaboration demonstrates how radio and infrared astronomy can work together to uncover objects that would otherwise remain difficult to study.

A Small Galaxy With a Big Scientific Story

The galaxy that produced FRB 20240304B surprised the research team.

Rather than coming from a large, mature galaxy, the burst originated in a relatively small galaxy with a low abundance of elements heavier than hydrogen and helium. Astronomers describe these heavier elements collectively as metals.

The galaxy is also undergoing vigorous star formation, meaning it is actively producing new stars.

These characteristics provide important clues about the possible origin of the radio burst.

Massive stars live relatively short lives on astronomical timescales. When they reach the end of their lives, some explode as supernovas and leave behind neutron stars. Under suitable conditions, these remnants can become magnetars.

A young, actively star-forming galaxy is therefore a promising environment for the formation of magnetars.

The researchers suggest that this discovery provides fresh evidence supporting the idea that at least some fast radio bursts originate from young magnetars.

It does not prove that all FRBs have the same origin. Instead, it adds an important piece of evidence that scientists can compare with observations of other bursts and their host galaxies.

Understanding these environments may eventually reveal why some galaxies produce FRBs and how the objects responsible for these signals form and evolve.

Using Radio Bursts to Map Invisible Matter

The discovery is not just about identifying a distant galaxy. The radio burst also provides a new way to investigate the material spread throughout the universe.

Most of the space between galaxies is not completely empty. It contains thin, diffuse gas and other forms of matter that are difficult to observe directly.

As radio waves travel through this material, their different frequencies can be affected in measurable ways. By studying these changes, astronomers can estimate how much matter the signal encountered along its journey.

This is particularly useful because a large amount of ordinary matter exists in the space between galaxies rather than being concentrated inside stars and planets.

Fast radio bursts can therefore serve as cosmic probes, helping scientists investigate the distribution of matter across enormous distances.

By studying bursts from different distances, researchers can compare how the amount and distribution of matter changed over cosmic time. These measurements could improve our understanding of galaxy formation, the evolution of cosmic structures and the composition of the universe.

In this way, a signal that lasts only milliseconds can provide information about billions of years of cosmic history.

Could Astronomers Detect Signals From the First Stars?

The discovery also raises an exciting possibility: fast radio bursts may eventually allow astronomers to investigate even earlier stages of the universe.

Researchers believe that sufficiently powerful bursts could, in principle, be detectable from much earlier cosmic periods, potentially approaching the era when the first generations of stars began to form.

That would allow scientists to explore environments that are difficult to study using conventional observations of distant galaxies.

However, detecting such signals will require highly sensitive radio telescopes, accurate identification of their host galaxies and advanced methods for measuring their distances.

The James Webb Space Telescope will remain especially important because it can investigate faint, distant galaxies that ground-based instruments may struggle to detect.

As radio telescopes become more capable, astronomers hope to discover additional bursts from increasingly distant regions of space.

Professor Ben Stappers of the University of Manchester, who is also a principal investigator of the MeerTRAP project, has emphasized the importance of pushing this observational frontier farther toward the universe's earliest stellar generations.

A New Window Into the Distant Universe

The discovery of FRB 20240304B represents an important step forward in astronomy. It establishes a new distance record for fast radio bursts and demonstrates the power of combining radio observations with the infrared capabilities of the James Webb Space Telescope.

More importantly, it shows that these brief flashes can do much more than reveal mysterious energetic events. They can help scientists investigate the galaxies in which they originate, explore the formation of magnetars and trace matter distributed across the universe.

Although many questions about fast radio bursts remain unanswered, every well-studied event adds another piece to the puzzle.

A signal that lasted only milliseconds has now provided a glimpse into a universe just three billion years old. As researchers continue searching for more distant bursts, these cosmic flashes could become essential tools for understanding how the universe developed from its early stages into the vast cosmos we observe today.

Reference: Manisha Caleb et al., A fast radio burst at redshift 2, three billion years after the Big Bang, published in Science. DOI: 10.1126/science.adz2675.