The Milky Way Might Not Smash Into the Andromeda Galaxy After All, New Simulation Indicates

Gizmodo

02-06-2025

For over a decade, researchers have suggested a high possibility of our Milky Way galaxy smashing into neighboring galaxy Andromeda around 5 billion years from now. The collision would merge the two galaxies into a single (very creatively named) 'Milkomeda'—but new research now indicates that this is less likely than previously assumed.
Integrating new data from the Gaia and Hubble telescopes, an international team of researchers has simulated our galaxy's movement for the next 10 billion years. The computer model also makes use of new mass estimates for other galaxies within the Local Group—a galactic group that hosts the Milky Way and Andromeda, among others. Ultimately, the simulation indicates that there is only about a 50% probability that the two galaxies will collide in the next 10 billion years, bolstering similar results from previous studies.
'Here we consider the latest and most accurate observations by the Gaia and Hubble space telescopes, along with recent consensus mass estimates, to derive possible future scenarios and identify the main sources of uncertainty in the evolution of the Local Group over the next 10 billion years,' the researchers, including experts from the University of Helsinki and Durham University, wrote in the study. 'We found that uncertainties in the present positions, motions and masses of all galaxies leave room for drastically different outcomes and a probability of close to 50% that there will be no Milky Way–Andromeda merger during the next 10 billion years.'
'The fate of our Galaxy is still completely open.'
Just as planets exert gravitational forces on each other, galaxies also impact their galactic neighbors. Specifically, Andromeda, the Triangulum galaxy, and the Large Magellanic Cloud (a galaxy orbiting the Milky Way) influence the Milky Way's path. According to the researchers, previous analyses that calculated higher chances likely didn't factor in the gravitational pull of the Large Magellanic Cloud. 'The orbit of the Large Magellanic Cloud runs perpendicular to the Milky Way–Andromeda orbit and makes their merger less probable,' they explained.
Their simulation also accounted for uncertainties, another factor that could have lowered the probability. Still, the team highlights the fact that even with the newest information, there are still a number of unknowns that make it difficult to determine exactly how the Milky Way and Andromeda will move, although more data from the Gaia telescope could continue to refine their predictions.
While 'Milkomeda' might never come to life, the researchers did find another highly likely collision almost certainly slated for sometime in the next two billion years: a Milky Way–Large Magellanic Cloud merger (I don't even want to know what they'd call the resulting galaxy).
Nevertheless, 'the fate of our Galaxy is still completely open,' they concluded.