For decades, astronomers have looked to the distant future and braced for the inevitable: a fiery, universe-altering collision between the Milky Way and its cosmic neighbor, Andromeda. But new findings suggest that fate may be much murkier than previously thought.
Using data spanning more than ten years from NASA’s Hubble Space Telescope and ESA’s Gaia mission, researchers have re-examined the long-standing belief that a head-on collision between the two galaxies is a cosmic certainty.
The verdict? There is a 50-50 chance that they will collide within the next 10 billion years, far from the previously accepted guarantee of a clash within 4.5 billion years.
The key to this uncertainty lies in the intricate gravitational dynamics of the Milky Way’s surroundings. The Large Magellanic Cloud (LMC), a satellite galaxy orbiting the Milky Way, is a wildcard in this equation.
According to the latest simulations, its gravitational influence could significantly alter the Milky Way’s trajectory, making the anticipated collision with Andromeda less likely than once believed.
Lead researcher Till Sawala, an astronomer at the University of Helsinki, emphasized that despite the precision of modern observational tools, predicting the long-term fate of galactic interactions remains a game of probabilities rather than definitive outcomes.
“Even using the best data available today, the future of the Local Group remains an open question. There’s an equal chance that the Milky Way and Andromeda will merge—or that they will continue their cosmic dance indefinitely,” Sawala explained.
The study incorporated 100,000 Monte Carlo simulations that factored in 22 different variables affecting the potential collision scenario. While many of these simulations still indicated an eventual merger, they also introduced the possibility of a near miss, where the two galaxies approach each other but remain gravitationally bound, never fully merging.
While a galactic collision of this scale would trigger an immense burst of star formation and cataclysmic rearrangement, scientists note that such an event—should it happen—is too distant to be of any concern to life on Earth. Long before a galactic merger reshapes the night sky, the Sun will have evolved into a red giant, rendering our planet inhospitable.
For now, astronomers must continue refining their predictions and collecting ever more precise data to uncover what truly lies ahead for our cosmic home.
Journal Reference:
- Sawala, T., Delhomelle, J., Deason, A.J. et al. No certainty of a Milky Way–Andromeda collision. Nat Astron (2025). DOI: 10.1038/s41550-025-02563-1
