2023-11-13 10:07:13
Far, far away, when the Universe was barely a few billion years old, there floats a galaxy strangely similar to ours. And astronomers don’t really know what to think about it.
This distant formation, known as ceers-2112, was recently identified by an international team of researchers through the analysis of images taken by the near-infrared camera of the télescope spatial James Webb (JWST).
Header image: artistic representation of the barred spiral galaxy ceers-2112, observed in the early universe. The Earth is reflected in an illusory bubble surrounding the galaxy, recalling the connection between the Milky Way and ceers-2112. (Luca Costantin/ CAB/ CSIC-INTA)
While an initial analysis of the images revealed little more than a blur, a closer look using a range of wavelengths added by Hubble showed the ancient system for what it was: a complex, barred spiral structure, just like the Milky Way, but a bit smaller.
Galaxies come in all sorts of shapes, sizes and luminosities that betray their evolutionary history. Some are large and bloated, others small and irregular, still others gigantic and stretched. And then there are those, like ours, that swirl, with stars and gas concentrated in radiant lines that curve like cosmic ribbons escaping from a spinning gymnast.
Although many factors influence the shape of a galaxy, from collisions to the concentration of neighboring galaxies, complex shapes have long been thought to take time. Generally, it is believed that barred spiral galaxies like the Milky Way did not exist for about 8 billion years. Yet a measurement of ceers-2112’s light stretching suggests that it already had a rather sophisticated appearance just 2 billion years after the Big Bang.
In our current universe, approximately two-thirds of all galaxies spirales are “crossed out“, meaning they have a huge bar-like structure running through their center. This structure is made up of gas and dust that is transported from the ends of the galaxy to its core, fueling star formation and the growth of supermassive black holes.
Representation of our barred spiral galaxy, the Milky Way. (NASA/JPL)
Although the ceers-2112 galaxy is still too faint to see the details of its spiral armsthe detection of a thickened bar in its center is enough to convince astronomers that ceers-2112 is remarkably well developed for its age.
According to Alexander de la Vega, astronomer at the University of California at Riverside (United States):
Almost all bars are found in spiral galaxies. The ceers-2112 bar suggests that galaxies have matured and become ordered much more quickly than we thought, meaning that some aspects of our theories about galaxy formation and evolution need to be revised.
Galaxies are more or less vast concentrations of dust and gas that come together under the influence of gravity. Some of this gravity is provided by the debris itself, but a significant proportion is believed to be the result of black matter. When enough matter is gathered at a given point, nuclear fusion can occur, giving rise to stars and their less sparkling offspring, the planets. At the same time, the sum of inertia contained in the swirling dust and moving suns can cause the nascent galaxy to rotate.
The mixture of forces, in the form of angular momentum, from the gravitational attraction and inertia of the free-falling masses, can end up flattening the galactic mass into a disk shape. Because some stars are drawn into less circular paths than others, orbital aberrations can slowly amplify, affecting other stellar paths to form distinct structures that we see as bars.
Another example of a barred spiral galaxy, NGC 1073, which closely resembles the Milky Way and photographed here by the Hubble Space Telescope. (NASA & ESA)
In turn, structures such as bars or neighboring galaxies can exert their influence on the propagation of objects in a galaxy, producing vast ripples that appear as spirals as the galaxy rotates.
As one might imagine, galaxy formation should require sustained forces acting over long periods of time. Still, the discovery of ceers-2112 might lead us to reconsider what is needed to transform a nebulous blob into a majestic whirlwind.
Still according to de la Vega:
In the past, when the Universe was very young, galaxies were unstable and chaotic. It was thought that bars could not form or last long in galaxies in the early Universe.
This discovery adds to a whole series of recent and unexpected discoveries concerning the conditions of the early Universe, galaxies that are too bright or early black holes that grow too quickly. As JWST continues to provide stunning images of the early cosmos, we will undoubtedly learn not only how galaxies like ceers-2112 came to be, but also how our own galaxy became as astonishing as she is today.
In January of this year (2023), the JWST already spotted, 11 billion light years away, barred spiral galaxies that were too advanced in their evolution.
The study published in Nature: A Milky Way-like barred spiral galaxy at a redshift of 3 and announced on the website of the University of California at Riverside: Milky Way-like galaxy found in the early universe.
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