Billions of light-years from Earth, a baby galaxy that’s surprisingly similar to our own is lurking, surprisingly calm and shameful, scientists said in research published Wednesday. The scientists said the discovery changed their understanding of how galaxies form.
The galaxy, named SPT0418-47, is located 12 billion light-years from Earth, according to a study published in the journal Nature. Astronomers at the Max Planck Institute for Astrophysics (MPI) saw the young galaxy with the Atacama Large Millimeter / Submillimeter Array (ALMA), one of the most powerful telescopes in the world.
Even the most powerful telescopes struggle to capture detailed observations of such distant galaxies. But with an effect called gravitational lensing, the team used the help of the gravity of a nearby town to act as a magnifying glass, allowing ALMA to look “into the distant past in unusual detail.”
The galaxy appears as an almost perfect ring of light – a so-called “Einstein ring.”
ALMA (ESO / NAOJ / NRAO), Rizzo et al.
Because the galaxy is so far away, astronomers view it as it was when the universe was just 1.4 billion years old. They said that SPT0418-47 is “surprisingly unchaotic” – contrary to prevailing theories that all young galaxies are “turbulent and unstable” compared to more mature galaxies such as the Milky Way.
“What we found was quite surprising; despite the formation of stars at a high rate, and therefore the site of very energetic processes, SPT0418-47 is the most well-ordered galaxy disk ever observed in the early Universe, “Co-author Simona Vegetti, of MPI, said in a press release Wednesday. “This result is quite unexpected and has important implications for how we think galaxies evolve.”
SPT0418-47 does not appear to have spiral arms like the Milky Way. But both SPT0418-47 and our galaxy have rotating disks and bumps – large groups of tightly packed stars around their centers.
MPA / Rizzo et al.
“This result represents a breakthrough in the field of galaxy formation, which shows that the structures we observe in nearby spiral galaxies and in our Milky Way were already 12 billion years ago,” said co-author Francesca Rizzo, a PhD student of MPI.
Researchers reconstructed the true shape of the galaxy and the motion of its gas from ALMA data using a new model for model computer. “When I first saw the reconstructed image of SPT0418-47, I could not believe it: a treasure chest was opened,” Rizzo said.
This is the first time scientists have detected a bulge so early in the history of the universe, said the release – making SPT0418-47 the farthest “Milky Way look-alike”.
“The big surprise was to find that this galaxy is actually quite similar to nearby galaxies, contrary to all expectations of the models and earlier, less detailed, observations,” said co-author Filippo Fraternali, of Captain Astronomical Institute, University of Groningen in the Netherlands.
Studying a baby galaxy that allows astronomers to view the universe when it was just 10% of its current age is key to understanding how galaxies form and evolve. It is unclear how a well-ordered galaxy could have formed so quickly after the Big Bang, suggesting that the early universe may be less chaotic than once thought.
While they have several similarities, astronomers expect that SPT0418-47 will evolve into a galaxy unique to the Milky Way. They expect that it will eventually join the class of elliptical galaxies.
In the future, astronomers hope to discern just how ordinary these baby disk galaxies are, and how chaotic they are, in order to increase our understanding of the evolution of our own galaxy.
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