A beautiful ring of light on a black background: astronomers announced this Wednesday that they had tracked down an extremely distant “baby” galaxy, 12 billion light years away, which strangely resembles our Milky Way.
The galaxy, listed under the number SPT0418-47, is so distant that its light took more than 12 billion years to reach us: we see it as it was when the universe was only 1 , 4 billion years old, barely 10% of its current age, specifies a press release from the European Southern Observatory (ESO), which participated in this discovery. At that time, the galaxies were still forming.
– THAT (@ESO) August 12, 2020
Now this “baby” galaxy, flushed out by the powerful network of ALMA radio telescopes built in northern Chile, strangely resembles our Milky Way: same high density of stars around the galactic center (called a bulb) and the same rotating disk .
A surprise to astronomers who did not believe that this type of structure could have already formed 12 billion light years ago.
“The most distant lookalike in the Milky Way”
“This is the very first time that the presence of a bulb has been detected in such a young universe, which gives SPT0418-47 the status of the most distant look-alike in the Milky Way,” enthuses ESO.
Another big surprise: no trace of turbulence or instability within the galaxy which even seems surprisingly calm, “suggesting that the young universe was perhaps less chaotic than we thought even for a short time. shortly after the Big Bang ”.
“What we discovered is quite puzzling: Although it forms stars at a high rate and is the site of highly energetic processes, SPT0418-47 is the best ordered galactic disc observed to date in the young universe ”, specifies Simona Vegetti, of the German Max Planck Institute, co-author of the study published this Wednesday in Nature.
However, “this result goes against all the predictions of numerical simulations and previous observation data, which are less detailed,” says Filippo Fraternali of the University of Groningen in the Netherlands, who also participated in the study.