Shining Since the Dawn of Time: The James Webb Telescope Discovers the Most Distant Galaxy Ever Seen

Before him, Hubble had detected only one galaxy dating from the first 500 million years after the Big Bang. As for Spitzer, specializing in infrared, its small 85 cm mirror drastically limited its scope. Today, the JWST is gradually raising the veil of the primitive universe.

And now as part of the mirage spectroscopic observation program, it has just confirmed a galaxy at Z = 14.44, or 280 million years only after the birth of the universe. An incredible temporal leap.

Mom-Z14: a galaxy more brilliant than expected

This galaxy, nicknamed Mom-Z14, is not just a simple light point bordering on detection. It is remarkably brilliant for a time when the universe was still young, dense and dominated by neutral hydrogen. Such brightness calls into question the classic theoretical models: how could such a massive galaxy have formed so quickly?

JWST spectroscopic observations reveal that the light of Mom-Z14 comes mainly from young stars, and not from an active galactic nucleus (AGN) as is sometimes the case in the distant universe. No supermassive black hole in the center, therefore, but a probable population of very massive and very bright stars-perhaps the famous theorized supermassive stars to populate the primordial universe.

An amazing chemical cocktail

But that's not all: the chemical composition of Mom-Z14 intrigues. It has a nitrogen/carbon ratio greater than that of the sun, a rare but precious index. This suggests a complex chemical history, already enriched by one or more generations of stars who have lived, exploded and enriched their environment.

This profile strangely recalls that of ancient globular cluster of our own galaxy. These compact objects, populated by very old stars, are sometimes considered the relics of the primordial universe. Mom-Z14 could therefore offer us a direct overview of the environment to form these very old stars, connecting the first galaxies to the most archaic components of the Milky Way.

When the shape joins chemistry

Another intriguing revelation: the ultra-local galaxies observed by the JWST seem to be divided into two distinct morphologies: compact or extensive. Mom-Z14 belongs to the first category. And it is no coincidence: compact galaxies are also those that present the strongest nitrogen emissions.

A relationship therefore seems to exist between the physical form of a galaxy and its chemical composition, as if each type of galactic structure followed a clean evolving path. An exciting track to understand how the galaxies are born and evolve, from the primordial universe until today.

A first step towards a cosmic archeology

More than a technical performance, the discovery of Mom-Z14 illustrates the potential of the JWST to make galactic archeology. By comparing these distant galaxies with ancient stars of the Milky Way, astronomers try to reconstruct the complete history of the formation of galaxies, from the first sparks to our current heavens.

This research is part of one of the major axes of the JWST scientific program: the assembly of galaxies. How do the first structures appear? What is the role of chemistry, mass, environment? And how do these first objects give birth to galaxies like ours?

The future: even further, even earlier

This detection may only be the beginning. If the Roman space telescope, scheduled for the end of the decade, was born despite the budgetary risks, it could reveal hundreds of other galaxies of this type, and complement the work of pioneer of the JWST.

But in the meantime, it is James Webb who holds the torch on the border of our cosmic knowledge. And if Mom-Z14 seems to shine alone in the darkness of the beginnings of the universe, it especially announces a new era for astronomy: that where the first objects of the universe cease to be theories, to become observable, measurable, interpretable data.

Mom-Z14 does not only tell us what the universe was 13.5 billion years ago.
It also reveals to us how, perhaps, today's stars have started to shine.