An international team of astronomers has discovered the most distant “twin” galaxy to the Milky Way known to date. Using data collected by the James Webb Space Telescope, astronomers discovered that this spiral galaxy, called ceers-2112, features a bar of stars and gas similar to the Milky Way. The study was published Wednesday by the scientific journal Nature.
The now discovered galaxy already existed when the Universe was only about two billion years old. “It’s like seeing our galaxy go back in time,” said the study’s lead author, Luca Costantin, quoted by the Spanish newspaper El País.
Research shows that galaxies similar to ours already existed 11.7 billion years ago, “when the Universe was only 15% old,” says the astronomer.
“Ceers-2112 can be considered a galaxy similar to the Milky Way, with a barred spiral structure and a mass similar to that of our galaxy at that time in the life of the Universe,” explained Costantin.
The second author of the study, Pablo G. Pérez González, cited by the same newspaper, compares this discovery with that of a 100-year-old person, who has never seen himself in a mirror, and receives a letter with a self-portrait that a twin sister unknown sent him when he was 15 years old.
In the nearby Universe, most massive spiral galaxies, such as the Milky Way, have an elongated structure in their central region that resembles a bar. Until today, it was believed that barred galaxies only emerged during the second half of the evolution of the Universe, something that is questioned by the discovery of the galaxy ceers-2112.
“Galaxies didn’t always look like we see them today, as their structure and mass change throughout their lives. So while Milky Way-like galaxies are common in the nearby Universe, we thought they were extremely rare. in the past. At least, until today,” Pérez González said.
Until today, what was known about the morphology of distant galaxies was based on observations made with the Hubble telescope, observations that revealed that these galaxies have irregular structures, probably due to merger events.
Now, observations made with the James Webb telescope challenge scientists’ understanding of the Universe.
The galaxy ceers-212 was located in a region between the constellations Ursa Major and Boieiro and is the most distant Milky Way-like galaxy known to date.
Three years ago, the existence of another “twin” galaxy of the Milky Way, SPT0418-47, was announced, which was already a gigantic object when the Universe was barely 1.4 billion years old. However, this galaxy did not feature a bar of stars and gas.
“The Milky Way can have an infinite number of twins and we observe each of them at a different age in the Universe. Through the discovery of these twins we will be able to tell the story of the evolution of the Milky Way,” says Pérez González.
Source: TSF
