Astronomers have long predicted a grand collision between the Milky Way and its closest large neighbor, the Andromeda galaxy, but new research published in Nature Astronomy suggests that this outcome is far less certain. The latest simulations incorporating updated astronomical data estimate that the chance of a merger in the next 10 billion years is about 50/50.
Lead researcher Til Sawala from the University of Helsinki explains that the revised prediction is due to the incorporation of new observational data, including measurements from the European Space Agency’s Gaia mission and the Hubble Space Telescope. These updates allowed for a refined understanding of the galaxies’ motions, masses, and gravitational influences.
The inclusion of the Large Magellanic Cloud (LMC), the Milky Way’s largest satellite galaxy, has significantly altered the predictions. While the LMC’s influence reduces the odds of a merger with Andromeda, it increases the likelihood that the Milky Way will cannibalize this satellite galaxy itself within 2 billion years.
New simulations paint a more complex picture of possible encounter scenarios. A direct collision is now considered unlikely, with less than 2% chance. Instead, the galaxies are likely to fly past each other initially, losing orbital energy before potentially merging. The uncertainty surrounding their closest approach also makes it difficult to predict whether they will merge or not.
This revised prediction fundamentally alters our understanding of the future dynamics of our galactic neighborhood. The Milky Way and Andromeda may coexist for billions of years longer without drastically disrupting each other’s structures or star systems.
Source: https://dailygalaxy.com/2025/06/milky-way-and-andromeda-collision