JWST Captures Light from Oldest Known Supernova Linked to Gamma-Ray Burst, 730 Million Years Post-Big Bang

The James Webb Space Telescope (JWST), utilizing its powerful infrared capabilities, has successfully detected the most distant stellar explosion ever recorded. This event, a supernova intrinsically connected to a powerful Gamma-Ray Burst (GRB), has been designated GRB 250314A. Astonishingly, this cosmic fireworks display occurred when the universe was merely 730 million years old—representing just over five percent of its current age. Consequently, the light observed by astronomers began its journey across space more than 13 billion years ago.

The initial alert for this intense burst of gamma radiation was triggered on March 14, 2025. This detection was made possible by the Sino-French SVOM satellite, which was launched in 2024 specifically to monitor transient cosmic objects and investigate high-energy explosions throughout the cosmos. Following this initial sighting, a coordinated follow-up campaign was launched, involving NASA's Swift orbital telescope alongside major ground-based observatories, including the Nordic Optical Telescope and the European Southern Observatory's Very Large Telescope (VLT).

These subsequent observations were crucial in confirming the extreme distance of the event, establishing a high redshift value of approximately z = 7.3. This redshift measurement precisely places the event within the early universe, roughly 730 million years after the Big Bang. This finding shatters the previous JWST record for the most distant supernova, which had been observed when the universe was 1.8 billion years old. It marks a significant step forward in probing the cosmic dawn.

Approximately three and a half months after the initial GRB detection, the JWST’s Near-Infrared Camera (NIRCam) provided definitive confirmation of the associated supernova. This timing coincided perfectly with the expected peak luminosity of the stellar explosion. What is particularly illuminating is that the observed supernova exhibited characteristics remarkably similar to those seen in contemporary stellar collapses. This suggests that the fundamental stellar physics governing the demise of massive stars were already fully established and operational in the nascent universe.

Furthermore, the duration of this specific Gamma-Ray Burst was measured at around 10 seconds, a timeframe highly characteristic of the core-collapse mechanism in massive stars. This observation offers a direct window into the processes that seeded the early cosmos with heavy elements.

This landmark observation was executed under the Director's Discretionary Time rapid response program, marking the first time an associated host galaxy has been resolved for an event this distant. The comprehensive research findings were formally published in December 2025 in the esteemed journal, Astronomy & Astrophysics Letters. The study was spearheaded by lead researchers Andrew Levan of Radboud University and Bertrand Cordier from CEA Paris-Saclay. This breakthrough unequivocally demonstrates the JWST’s unparalleled capacity to capture fleeting, transient phenomena in the primitive universe. The team’s future endeavors are already focused on leveraging the afterglows of these gamma-ray bursts to conduct detailed characterizations of these ancient galaxies.