In a new study, astronomers have made a stunning discovery that our galaxy, Milky Way, had recently collided with another galaxy causing an explosion.
Through time, the Milky Way has grown and has collided with other galaxies – which were torn apart and devoured by the Milky Way.
With every collision, the galaxy develops wrinkles which continue to ripple through different families of stars and affect how they move and behave in space.
This discovery about the cosmic crash happening nearly billions of years later than we thought was revealed by ESA’s Gaia space telescope.
Milky Way’s wrinkles hide the lost history of the galaxy
The telescope is aimed at unravelling the history of our galaxy by looking into these wrinkles.
“We get wrinklier as we age, but our work reveals that the opposite is true for the Milky Way. It’s a sort of cosmic Benjamin Button, getting less wrinkly over time,” said Thomas Donlon, lead author of the new Gaia study, which was published in Monthly Notices of the Royal Astronomical Society.
“By looking at how these wrinkles dissipate over time, we can trace when the Milky Way experienced its last big crash—and it turns out this happened billions of years later than we thought,” he added.
Gaia telescope discovered these galactic wrinkles in 2018. It was the first study which was able to accurately determine the time of the collision which led to the wrinkles by comparing observations with cosmological simulations.
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In an ESA release, study co-author Heidi Jo Newberg and an astronomer at Rensselaer Polytechnic Institute said, “For the wrinkles of stars to be as clear as they appear in Gaia data, they must have joined us less than three billion years ago—at least five billion years later than was previously thought.”
“New wrinkles of stars form each time the stars swing back and forth through the centre of the Milky Way. If they’d joined us eight billion years ago, there would be so many wrinkles right next to each other that we would no longer see them as separate features,” he added.
Donlon said that the three-billion-year-old collision likely happened between the Milky Way and a dwarf galaxy.
(With inputs from agencies)
Shambhu Kumar is a science communicator, making complex scientific topics accessible to all. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
