Astronomers have observed an interesting phenomenon in the distant universe, a galaxy very similar to the Milky Way, and it challenges the main theories about how galaxies evolve, according to a report prepared by CNN.
The distant system, called CEERS-2112, was observed by an international team using the James Webb Space Telescope.
Like our parent galaxy, the newly discovered Ceers-2112 galaxy is a barred spiral galaxy, and is now the most distant of its kind ever observed. The strip in the center of the structure is made of stars.
Ceers-2112 formed shortly after the Big Bang (estimated to be 13.8 billion years old), and the galaxy’s distinctive structure was already in place 2.1 billion years later.
Given the distance between Earth and objects from the earliest days of the universe, when telescopes like James Webb observe light from the distant universe, it’s like looking back into the past.
“Unexpectedly, this discovery reveals that galaxies similar to ours already existed 11,700 million years ago, when “The universe only has 15 percent of its life.”
Astronomers were surprised to see such an organized and well-arranged galaxy at a time when other galaxies were more irregular, according to the study. While massive spiral galaxies are common in the cosmic neighborhood of the Milky Way, this was not always the case.
This discovery, made possible by James Webb’s extremely sensitive light-detection capabilities, changes scientists’ understanding of galaxy formation and the early stages of the universe.
“Finding CEERS-2112 shows that galaxies in the early universe could have been arranged like the Milky Way,” study co-author Alexander de la Vega, a postdoctoral researcher at the University of California, Riverside, said in a statement.
He added: “This is surprising because galaxies were much more chaotic in the early universe and very few of them had structures similar to the Milky Way.”
Astrophysicists Pablo J. Pérez Gonzalez (left) and Luca Costantin at the Astrobiology Center in Torrejon de Ardoz
Early evolution of barred spiral galaxies
Astronomers believed that barred spiral galaxies like the Milky Way did not appear until after the universe had reached at least half its current age because it was believed that it took several billion years of galactic evolution before the massive clusters of stars within galaxies could form central bars. .
Bars form when stars orbit inside spiral galaxies in an organized manner, as they do in the Milky Way. Until now, astronomers did not believe that early galaxies were stable enough to form or persist bars.
But the discovery of Ceers-2112 indicates that this evolution took only about a billion years or less, de la Vega said.
He explained that “almost all bars are found in spiral galaxies,” pointing out that “the bar in CEERS-2112 indicates that galaxies have matured and become organized much faster than we previously thought, which means that some aspects of our theories about the formation and evolution of galaxies need to be revised.” ».
Dark matter
According to de la Vega, astronomers will need to change their theoretical models of how galaxies form and evolve by calculating the amount of dark matter present in the first galaxies.
Although dark matter has not actually been discovered, it is thought to make up 85 percent of the total matter in the universe, something the European Space Agency’s Euclid telescope is designed to map. Dark matter may have played a role in the formation of the bars.
This discovery also indicates that bars can be detected in early galaxies, even though the oldest galaxies are much smaller.
De la Vega emphasized that “the discovery of CEERS-2112 paves the way for the discovery of more bars in the young universe,” and added: “At first, I thought that discovering and estimating the properties of bars in galaxies like CEERS-2112 would be fraught with measurement uncertainties.” “But the power of the James Webb Space Telescope and the expertise of our research team helped us place strong constraints on the size and shape of the bar.”
