Back in 2024, scientists detected the farthest fast radio burst we’ve ever seen to date, thanks to observations by the MeerKAT ground telescope array. Fast radio bursts are ultra-fast radio waves from deep space, which last a fraction of a second but release as much as energy as what the sun emits in three days. They were first discovered in 2007, and not much is known about them. Now, astronomers have used the James Webb telescope to pinpoint the origin of the burst detected in 2024, and it could shed light on the phenomenon’s origins. 

Webb’s near-infrared instruments detected a galaxy in the right location from where the burst had come. Based on measurements from the way its light stretches, the fast radio burst occurred just 3 billion years after the Big Bang. Its origin galaxy existed way back when star formation was at its peak in the universe. In addition, the galaxy that produced it is also 1,000 times smaller than expected. The previous fast radio bursts we’ve detected took place billions of years later in massive, star-forming galaxies. 

There are a couple of theories on how fast radio bursts are produced. One proposes that they’re generated by the merger of two neutron stars. But it takes billions of years before two neutron stars — the collapsed cores of massive supergiant stars — collide, which means that bursts can only come from older galaxies. 

Another theory suggests that the bursts can come from massive stars exploding in a supernova and leaving behind magnetars, which are rare type of neutron stars that have highly powerful magnetic fields. “Our work suggests that it’s very unlikely that this [fast radio burst] was produced by a merger,” said Manisha Caleb from the University of Sydney, Australia, who served as lead author on the study published in Science. In other words, their work shows that the origin of this burst was likely a supernova, providing support for the theory that fast radio bursts can come from a certain type of star explosion.