2023-11-15 05:15:00
(CNN) — Astronomers have discovered an intriguing phenomenon in the distant universe – a galaxy that looks a lot like the Milky Way – and it’s challenging key theories regarding how galaxies evolve.
The distant system, called ceers-2112, was discovered by an international team thanks to the James Webb Space Telescope.
Like our home galaxy, the newly discovered ceers-2112 is a barred spiral galaxy and is now the most distant of its kind ever observed. The bar in the center of the structure is made of stars.
Ceers-2112 formed shortly following the Big Bang created the universe (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 early days of the universe, when telescopes like the Webb observe light from the distant cosmos, it’s like looking into the past.
“Unexpectedly, this discovery reveals that galaxies similar to ours already existed 11.7 billion years ago, when the Universe was only 15% old,” the study’s lead author, Luca Costantin, said in a statement. He is a postdoctoral researcher at the Higher Scientific Council of Spain at the Spanish Astrobiology Center in Madrid.
Astronomers were surprised to see such a well-ordered and structured galaxy at a time when others were much more irregular. While massive spiral galaxies are common in the cosmic neighborhood of the Milky Way, this has not always been the case.
The revelation, made possible by Webb’s highly sensitive light detection capabilities, is changing scientists’ understanding of galaxy formation and the early stages of the universe.
“Finding ceers-2112 shows that galaxies in the early universe might be as ordered as the Milky Way,” study co-author Alexander de la Vega, a postdoctoral researcher at the University of California, Riverside, said in a statement. “This is surprising because galaxies were much more chaotic in the early universe and very few had structures similar to the Milky Way.”
A study detailing the findings was published Nov. 8 in the journal Nature.
Early evolution of barred spiral galaxies
Astronomers thought that barred spiral galaxies, like the Milky Way, did not appear until the universe reached at least half its current age because it was believed that several billion years of galactic evolution were needed before the enormous collections of stars within galaxies might form central bars.
Bars take shape when stars within spiral galaxies rotate in an orderly manner, as they do in the Milky Way. Until now, astronomers did not believe that early galaxies had enough stability for bars to form or persist.
But the discovery of ceers-2112 suggests that this evolution only took regarding a billion years or less, de la Vega said.
“Almost all bars are found in spiral galaxies,” de la Vega said. “The bar in ceers-2112 suggests that galaxies matured and ordered much faster than we previously thought, meaning that some aspects of our theories regarding galaxy formation and evolution need revision.”
Dark matter research
De la Vega believes that astronomers will need to alter their theoretical models of how galaxies form and evolve taking into account the amount of dark matter included in the most primitive galaxies.
While dark matter has never been detected, it is believed to make up 85% of the total matter in the universe, and is something the European Space Agency’s Euclid telescope was designed to do. It is possible that dark matter played a role in the formation of the bars.
The discovery also suggests that bars can be detected in early galaxies, even though older galaxies are much smaller.
“The discovery of ceers-2112 paves the way for more bars to be discovered in the young universe,” de la Vega said. “At first I thought that detecting and estimating the properties of bars in galaxies like ceers-2112 would be plagued by measurement uncertainties. But the power of the James Webb Space Telescope and the experience of our research team helped us place strong limitations on the size and shape of the rod.”
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