The James Webb telescope is watching one of the earliest supernovas in the universe unfold

Astronomers using the James Webb Space Telescope (JWST) have found what may be one of the most distant supernovas ever observed.

And in a stroke of cosmic luck, the team thinks they're seeing what the explosion looked like just days after it ignited.

The supernova, named AT 2026abck, dates to around 1.15 billion years after the Big Bang , when the universe was less than one-tenth of its current age and bursting with massive stars flickering into life.

The massive exploding star violently released its light over 12.5 billion years ago, according to the researchers — so long ago that the distance between us has effectively ballooned sixfold due to the expansion of the universe .

The discovery was described in a paper that was uploaded to the preprint server arXiv Sept.

29 and has not yet been peer reviewed.

According to the study authors, this ancient speck of light is stupendously bright.

"At its peak, the supernova is about 8 billion times the brightness of the sun … almost as bright as the whole Milky Way Galaxy," study co-author Xiaohui Fan , an observational cosmologist and professor of astronomy at the University of Arizona, told Live Science via email.

"Over the course of the explosion, it radiates the energy that the sun will radiate over about 2 billion years." A beacon from the beginning of space-time The newly discovered supernova shines brilliantly at over 30,000 degrees Fahrenheit (16,000 degrees Celsius).

Its incandescent shell of ejected material has billowed to a radius of approximately 46 astronomical units ‪—‬ about 46 times the distance between Earth and the sun, or about as far as Pluto swings at its farthest point from the sun.

The supernova's host galaxy, designated ID101411, holds about 6.3 billion solar masses and is "forming new stars more than ten times faster than our Milky Way," first author Mingyang Zhuang , an observational astrophysicist at the University of Illinois Urbana-Champaign, told Live Science via email.

As with other early galaxies, ID101411 is deficient in metals, meaning any elements heavier than hydrogen and helium, because not enough time had passed to create those heavier elements in the forges of massive stars and their apocalyptic explosions.

An illustration of a supernova erupting when the universe was just 730 million years old. (Image credit: NASA, ESA, CSA, STScI, L.

Hustak (STScI)) The study authors estimate that they observed the supernova as it would have looked just four to 10 days after it exploded.