Astronomers using the James Webb Space Telescope have identified AT 2026abck, potentially one of the most distant supernovas ever observed. The explosion occurred roughly 1.15 billion years after the Big Bang, when the universe was less than a tenth of its current age. Researchers estimate that their observations capture its appearance just four to ten days after the blast began. At peak brightness, it was approximately eight billion times as bright as the sun, nearly rivalling the entire Milky Way.
Detected through the NEXUS Treasury programme, which repeatedly surveys selected regions for ancient explosions, the supernova appeared in observations on 7 August 2026 but was absent on 28 May. Although 71 days separated those observations on Earth, only about 12 days elapsed in the explosion’s own reference frame. Cosmic expansion stretches the arriving light, making the event appear to evolve approximately six times more slowly: changes lasting a week there unfold over about six weeks for observers here. Catching such a distant explosion so early required both repeated observations and fortunate timing. Unlike many similarly distant discoveries, this detection did not depend on gravitational lensing, the magnification of background light by a massive foreground object.
The host galaxy, ID101411, forms stars more than ten times faster than the Milky Way. The explosion may belong to the rare superluminous class, releasing tens or hundreds of times more energy than conventional supernovas. However, that interpretation remains preliminary. Further observations tracking whether the material heats up or cools could clarify the explosion’s nature, surroundings and cause.
