Scientists Have A New Estimate Of When The Andromeda Galaxy Will Smash Into The Milky Way

Thanks to a new study, scientists now have a revised estimate of when the Andromeda Galaxy will finally smash into the Milky Way, and things are looking much brighter for Earth than previously believed.

According to Space, the spiral Andromeda Galaxy will still be crashing into the Milky Way, but research through Europe's Gaia spacecraft has suggested that this massive collision will be occurring 4.5 billion years from now, rather than the previously estimated 3.9 billion years, giving humans a little longer to enjoy their sojourn on Earth without any disruption.

"This finding is crucial to our understanding of how galaxies evolve and interact," Gaia project scientist Timo Prusti noted.

The Gaia spacecraft was originally launched in 2013, and the purpose of its mission was to help scientists develop a modern and precise 3D map of the Milky Way galaxy, with scientists projecting that by the end of its mission, Gaia will have mapped one billion stars alone.

Despite Gaia mainly tracking stars in the Milky Way, it has also been busy keeping tabs on stars in the Triangulum, or M33, Galaxy, as well as the Andromeda, or M31, Galaxy.

Because these two galaxies are so close to the Milky Way, having been estimated to be between 2.5 million to 3 million light-years away from us, scientists involved in the latest study have suggested that there may even be some form of interaction between the galaxies.

Roeland van der Marel, from the Space Telescope Science Institute in Baltimore, explained that in their latest research, scientists used data released by Gaia in April, 2018, to learn more about the different motions experienced in these galaxies studied.
"We needed to explore the galaxies' motions in 3D to uncover how they have grown and evolved and what creates and influences their features and behavior. We were able to do this using the second package of high-quality data released by Gaia."
Through painstaking research, scientists were able to figure out the rotation rates for both the Triangulum and Andromeda galaxies, which allowed them to project how they will be moving over a period of billions of years into the future.

Through these models, scientists reached the conclusion that the Andromeda Galaxy will be colliding with the Milky Way much later than originally estimated. Not only that, but it also appears that rather than a head-on collision, these two galaxies will hit each other with more of a sideswipe than anything else.

According to Prusti, while Gaia may have been intended to create a map of stars, its latest observations have shown that it has gone well beyond what it was originally built for.

"Gaia was designed primarily for mapping stars within the Milky Way — but this new study shows that the satellite is exceeding expectations and can provide unique insights into the structure and dynamics of galaxies beyond the realm of our own. The longer that Gaia watches the tiny movements of these galaxies across the sky, the more precise our measurements will become."
The new study, which has suggested that the Andromeda Galaxy will collide with the Milky Way later than expected, has been published in the Astrophysical Journal.