A fleeting flash of radiation lasting just ten seconds has become one of the most important astronomical observations ever recorded. After traveling for more than 13 billion years, the signal reached Earth in March 2025, offering scientists a direct glimpse into a time when the universe was less than a billion years old, as reported by The Daily Galaxy.
The event was first detected by SVOM, a joint French-Chinese satellite designed to spot transient cosmic phenomena. The burst, later designated GRB 250314A, was identified as a long-duration gamma-ray burst, a class of events typically associated with the collapse of massive stars into black holes.
Follow-up observations quickly turned this detection into a record-breaker. Data from the Neil Gehrels Swift Observatory and ground-based facilities including the Very Large Telescope allowed astronomers to measure the burst’s redshift at 7.3, according to the ESA’s mission report. That places the explosion just 730 million years after the Big Bang, during the Epoch of Reionisation, when the first stars and galaxies were transforming the universe from darkness into light.
The source of a super bright flash of light known as a gamma-ray burst: a supernova that exploded when the Universe was only 730 million years old. Credit: NASA, ESA, CSA, STScI, A. Levan (IMAPP), Image Processing: A. Pagan (STScI)
The final confirmation came months later from the James Webb Space Telescope. Using its NIRCam and NIRSpec instruments, Webb observed the fading afterglow and, for the first time at such an extreme distance, identified the host galaxy of a supernova. This confirmed that GRB 250314A originated from the death of a massive star, making it the most distant supernova ever verified.
What surprised researchers most was how familiar the explosion looked. Instead of displaying exotic traits expected from primordial Population III stars, the data matched a standard Type II supernova, similar to those seen in the nearby universe today. This suggests that stellar life cycles and chemical enrichment were already well established remarkably early in cosmic history.
According to the research teams involved, the finding challenges long-standing assumptions about how quickly galaxies evolved after the Big Bang. If massive stars were already dying in “modern” ways so early on, it implies that multiple generations of stars may have formed far faster than current models predict.
Beyond the record itself, the discovery highlights the growing power of coordinated, global astronomy. By combining rapid gamma-ray detection with deep infrared follow-up, scientists are now able to probe eras of the universe that were previously inaccessible.
With additional observing time already secured on Webb, astronomers expect more signals like this to emerge. Each brief flash carries the potential to rewrite what we know about the universe’s first billion years.