Astronomers have found a "Milky Way look-alike" galaxy in deep space, 12 billion light-years from our own, according to a new study.
The research, published in Nature, details the discovery of galaxy SPT0418-47, which not only has surprised the researchers but looks similar to other nearby galaxies, throwing a wrench into what experts previously knew about galaxy formation.
“This result represents a breakthrough in the field of galaxy formation, showing that the structures that we observe in nearby spiral galaxies and in our Milky Way were already in place 12 billion years ago,” said the study's lead author, Francesca Rizzo, a doctoral student from the Max Planck Institute for Astrophysics in Germany, in a statement.
Astronomers using ALMA, in which the ESO is a partner, have revealed an extremely distant galaxy that looks surprisingly like our Milky Way. The galaxy, SPT0418-47, is gravitationally lensed by a nearby galaxy, appearing in the sky as a near-perfect ring of light. (Credit: ESO)
SPT0418-47 was spotted by Chile's Atacama Large Millimeter/submillimeter Array (ALMA) using a technique known as "gravitational lensing," which helps researchers find objects in the distant universe. At 12 billion light-years away, SPT0418-47 is less than 2 billion years younger than the universe itself.
A light-year, which measures distance in space, is approximately 6 trillion miles.
The astronomers found SPT0418-47 does not have spiral arms and is extremely "well-ordered," study co-author Simona Vegetti added. It does have a rotating disc and bulge, the first time this type of galaxy has been seen that deep into the universe.
“What we found was quite puzzling; despite forming stars at a high rate, and therefore being the site of highly energetic processes, SPT0418-47 is the most well-ordered galaxy disc ever observed in the early Universe,” Vegetti added. “This result is quite unexpected and has important implications for how we think galaxies evolve."
To reconstruct the galaxy's true shape, the researchers used computer models and took the images made of "gravitational lensing" and reconstructed them, which astonished Rizzo.
"When I first saw the reconstructed image of SPT0418-47 I could not believe it," Rizzo explained. "A treasure chest was opening."
Though SPT0418-47 has some similar features to other spiral galaxies, it's expected it will evolve into an elliptical galaxy, the researchers added.