Astronomers observe gamma-ray burst from 13 billion years ago

An international team of astronomers has recorded a short gamma-ray burst (GRB) originating just hundreds of millions of years after the Big Bang, marking the oldest supernova ever directly observed, according to a study published in Astronomy & Astrophysics.

In March 2025, scientists detected a brief but intense flash of high-energy light lasting around ten seconds.

Subsequent analysis revealed that the signal had travelled across space for approximately 13 billion years before reaching Earth, offering a unique glimpse into the early history of the Universe, when it was just 730 million years old.

The event, designated GRB 250314A, is believed to have resulted from the collapse of a massive star in one of the earliest known galaxies.

Detection of the cosmic signal

The burst was first recorded on March 14, 2025 by the French-Chinese satellite SVOM, specifically designed to detect gamma-ray bursts – the most powerful explosions in the Universe. Within 90 minutes, NASA’s Swift Observatory pinpointed the source, allowing ground-based telescopes in Chile and the Canary Islands to observe the afterglow.

Infrared analysis showed that the light had been significantly stretched due to the expansion of the Universe, confirming that the explosion occurred in a very early cosmic epoch.

Months after the initial burst, the James Webb Space Telescope was able to distinguish the supernova’s glow from the faint light of its host galaxy. This provided direct confirmation of the massive star’s collapse and explosion in the young Universe.

According to the researchers, GRB 250314A represents the most ancient supernova observed through direct measurements.

Despite expectations that the first stars would be far more extreme, the supernova’s properties were strikingly similar to those of stellar explosions in the relatively nearby Universe.

Implications for early sosmic history

Lead researcher Andrew Levan of Radboud University said the findings suggest that the fundamental processes of star formation and death were already in operation less than a billion years after the Big Bang.

GRB 250314A occurred during the so-called epoch of reionisation, when the first stars and galaxies were gradually shaping the Universe. Explosions like this helped disperse heavy chemical elements, which later formed planets and, eventually, life.

By Aghakazim Guliyev