Scientists have discovered a galaxy consisting of primordial stars 2 billion years after the Big Bang

An international team of scientists has discovered a galaxy that appears to be made up of the very first stars in the universe - so-called Population III. The unusual discovery is that this galaxy existed approximately 11 billion years ago, when the Universe was about two billion years old. According to existing ideas, by that time there should have been no such “primordial” stars left. The study was published in The Astrophysical Journal Letters.

The MPG-CR3 galaxy was discovered using the James Webb Space Telescope and ground-based observatories. It shows the predominance of helium and hydrogen - the simplest elements that appeared immediately after the Big Bang. At the same time, “heavy” elements such as oxygen, carbon or iron, which are produced inside stars, are practically not visible in its spectrum. The metal content in this galaxy turned out to be less than one percent of the solar one - it is chemically almost as “pure” as the early Universe.

The analysis showed that the stars in this galaxy are only about two million years old - by cosmic standards, these are babies. The entire galaxy weighs approximately six hundred thousand Suns—very light by galactic standards. The ratio of different types of radiation indicates that there is practically no cosmic dust in the galaxy, which is typical for very young systems that have not evolved chemically. The galaxy's characteristics—a lack of metals and an abundance of hydrogen—match well with theoretical predictions for Population III stars.

Interestingly, the galaxy is located in a relatively deserted region of space, where the density of matter is slightly below average. This may explain why pristine gas was preserved there: in such rarefied zones there is less influence from neighboring galaxies. They could “contaminate” the surrounding space with heavy elements.

Previously, it was believed that such stars formed only in a very early era, when the Universe was less than a billion years old. The find shows that “pockets” of primordial gas could persist for much longer - perhaps in secluded corners of the cosmic “web”, where chemical pollution from ordinary galaxies did not reach.

Earlier, astronomers from the United States announced that the LAP1-B object was the first discovery that fully corresponds to theoretical predictions about the oldest stars in the Universe - Population III. These stars should have been formed from almost pure hydrogen and helium, without the heavy elements that appeared later.