Science

Astronomers find Milky Way look-alike galaxy 12 billion light-years away

Mumbai | Updated on August 16, 2020 Published on August 16, 2020

Milky Way. File photo   -  Reuters

It is likely to evolve into an elliptical galaxy, rather than a spiral

Astronomers at the Max Planck Institute for Astrophysics have found a look-alike of the Milky Way 12 billion light-years away with the help of the Atacama Large Millimetre/sub-millimetre Array (ALMA).

“The galaxy is so far away its light has taken more than 12 billion years to reach us,” the institute said in an official press release.

This makes it an even more fascinating discovery as according to the National Aeronautics and Space Administration (NASA) our universe is around 13 billion years, give or take a few billion.

“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,” says Francesca Rizzo, PhD student from the Max Planck Institute for Astrophysics in Germany, who led the research published in the journal Nature.

The galaxy, called SPT0418-47, does not appear to have spiral arms lie our Milky Way but has at least two features that are similar to our galaxy: a rotating disc and a bulge.

This is the first time a bulge has been seen this early in the history of the Universe, making SPT0418-47 the most distant Milky Way look-alike, researchers said.

“The big surprise was to find that this galaxy is actually quite similar to nearby galaxies, contrary to all expectations from the models and previous, less detailed, observations,” said co-author Filippo Fraternali, from the Kapteyn Astronomical Institute, University of Groningen in the Netherlands.

It is difficult for researchers to observe these galaxies even with the most powerful telescopes due to the distance. The team utilized a nearby galaxy as a powerful magnifying glass — an effect known as gravitational lensing to overcome this difficulty. This allowed ALMA “to see into the distant past in unprecedented detail. In this effect, the gravitational pull from the nearby galaxy distorts and bends the light from the distant galaxy, causing it to appear misshapen and magnified.”

“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,” said co-author Simona Vegetti, also from the Max Planck Institute for Astrophysics. “This result is quite unexpected and has important implications for how we think galaxies evolve."

Though the galaxy is quite similar to ours, astronomers expect it to evolve into a galaxy very different from the Milky Way. It is likely to evolve into an elliptical galaxy, rather than a spiral.

Future studies will be conducted to further explore the evolution of these ‘baby’ disc galaxies including those with ESO’s Extremely Large Telescope.

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Published on August 16, 2020
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