That’s the conclusion reached by an international research team led by Carl Glazebrook of Swinburne University of Technology in Australia (Nature, February 14).
The astronomers’ findings are based on new spectroscopic data from the Webb Space Telescope. These show that the large galaxy in the early universe, which we observe as it was 11.5 billion years ago, has a very old population of stars that formed another 1.5 billion years before that. That seems impossible, because at the time there wasn’t enough dark matter clumped together to allow these stars to form.
Glazebrook’s team has been “hunting” for this particular galaxy for seven years, spending hours looking at it with the two largest telescopes on Earth (the Keck Telescope in Hawaii and the European Very Large Telescope in Chile) to find out its age. . But it was too weak to make meaningful measurements. Webb was the first telescope to confirm the nature of the galaxy.
Current theories of galaxy formation predict that the number of massive galaxies decreases sharply the deeper you look into the universe. But very massive and quiet galaxies were already observed one to two billion years after the Big Bang. This calls into question current theoretical models.
The main question now is how galaxies were able to form so early in the history of the universe, and what mysterious mechanisms ensured that star formation stopped while it continued elsewhere in the universe. It is also still unclear how many of these early galaxies exist. Further observations should reveal this.
