The furthest galaxy, JADES-GS-z14-0, is seen as it was around 300 million years after the Big Bang, existing at least 100 million years earlier than the previous record holder. That means that the light the JWST saw from this primordial galaxy has been traveling for 13.5 billion years on its way to reach us.

JADES-GS-z14-0 isn't alone, either. It was discovered along with another galaxy, JADES-GS-z14-1, that is almost as far away and takes second place in the ranking of the earliest galaxies ever seen by humanity.

The announcement of the discoveries, made in Oct. 2023 and Jan. 2024, are the latest developments in the ongoing investigation of cosmic dawn that the $10 billion telescope has facilitated as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. JADES aims to provide vital insights into the ways in which the stars, gas, and black holes were evolving in primordial galaxies when the 13.8 billion-year-old universe was very young.

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With a width of around 1,600 light-years across, this "cosmic dawn" galaxy is also remarkable for how big and bright it is.

"The size of the galaxy clearly proves that most of the light is being produced by large numbers of young stars, rather than material falling onto a supermassive black hole in the galaxy's center, which would [make it] appear much smaller, "JADES team leader Daniel Eisenstein from the Harvard & Smithsonian's Center for Astrophysics (CfA) said in a separate statement.

The extreme brightness of JADES-GS-z14-0 and the fact this luminosity is powered by young stars means this galaxy represents the most striking evidence for the rapid formation of large, massive galaxies in the early universe found thus far.

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JADES-GS-z14-0 has a redshift of z = 14.32, while the previous most distant galaxy, JADES-GS-z13-0, has a redshift of z = 13.2, which placed it as existing 400 million years after the Big Bang.

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When it was first spotted, the primordial galaxy was so close to a closer foreground galaxy that the team suspected they could be celestial neighbors. This idea was dispelled in October last year when the JADES crew spent five days performing a deep analysis of JADES-GS-z14-0 with NIRCam. The application of filters that are specifically tailored to identify early galaxies confirmed the extreme distance to JADES-GS-z14-0.

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Another surprise was the discovery of oxygen in JADES-GS-z14-0. Elements heavier than hydrogen and helium are forged by stars during their lifetimes and then distributed through galaxies when these stars explode. The observation of oxygen in JADES-GS-z14-0 could indicate that at least one generation of stars has already lived and died in this very early galaxy.

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Helton added that given the relatively small region of the sky that the JWST searched to find JADES-GS-z14-0, its discovery has profound implications for the predicted number of bright galaxies we see in the early universe.