Telescópio Espacial James Webb has identified the oldest supernova ever recorded by humanity. The explosion occurred when Universo was just 730 million years after Big Bang. The event, called GRB 250314A, was initially captured on March 14, 2025 and confirmed by the observatory’s NIRSpec instrument.
Observations taken three months after the initial glow revealed the host galaxy of the massive collapsed star. The detection represents a milestone in observational astronomy of primordial Universo.
Detection occurred in coordinated steps
The gamma ray burst lasted about ten seconds and was recorded by the SVOM mission, a French-Chinese satellite dedicated to transient phenomena.
In less than two hours, the Swift observatory located the X-ray source associated with the event.
The Telescópio Óptico Nórdico picked up the near-infrared afterglow, indicating extreme distance.
Very Large Telescope measured the redshift at z=9.88, confirming the cosmic age of 730 million years.
JWST spots very rare supernova recorded just 730 million years after Big Bang
— JAMES WEBB (@jameswebb_nasa)December 10, 2025
The Telescópio Espacial James Webb (#JWST) has just achieved a historic feat: identifying a supernova that exploded when the universe was just 730 million years old, about 5% of its…pic.twitter.com/sCMcIF85OM
Characteristics of early supernova
James Webb observed the phenomenon at the moment of the supernova’s estimated maximum brightness.
The light emitted was temporally stretched by the expansion of Universo, prolonging visibility for months.
Researchers highlight that only Webb has sufficient resolution to isolate the supernova signal among distant galaxies.
The image shows a faint red dot identified as GRB 250314A in a field full of hundreds of galaxies.
Surprisingly familiar behavior
Studies published in Astronomy & Astrophysics Letters compare the event with supernovae observed at the local Universo.
The light curve presents an evolution similar to the explosions of massive stars today.
Scientists expected significant differences due to the lower metallicity of the first stellar generations.
Results indicate that basic physical mechanisms have remained consistent since young Universo.
Host galaxy appears compact
The galaxy that housed the massive star features bright regions of active star formation.
Its light is concentrated in a few pixels in the Webb image, typical of extremely distant objects.
Structure resembles other galaxies observed in the same cosmic epoch.
International collaboration accelerated analysis
Teams from Europa, Estados Unidos and China coordinated observations in real time.
Quick follow-up was essential to capture the afterglow before it disappeared.
Two scientific papers detail direct supernova detection and multi-wavelength characterization.
Future research will use similar events to map distant galaxies with greater precision.
Rarity reinforces the importance of the find
Long gamma-ray bursts in the first billion cosmic years are extremely scarce.
Only a few similar cases have been recorded in the last five decades.
The GRB 250314A event highlights the unique ability of James Webb to study the primordial Universo.
New campaigns are already planning observations of similar transient phenomena.
The oldest supernova known to date paves the way to understanding the formation of the first massive stars and their chemical environments in the early Universo.
