A team of astronomers has reevaluated the predicted collision between the Milky Way and Andromeda galaxies, two of the largest in the Local Group. In a study published Monday, they found that the likelihood of this galactic clash is smaller than initially thought.
According to previous predictions, the Milky Way and Andromeda were on a collision course, with some estimates suggesting they would collide within 4-5 billion years. However, new research suggests that there is only about a 2% chance of a direct collision in that time frame.
The team ran over 100,000 simulations using data from the Hubble and Gaia space telescopes to account for uncertainties in the galaxies’ positions, velocities, and masses. These simulations showed that the two galaxies could pass close by each other but not collide, or they could merge as one galaxy.
In either case, the merger would likely involve a strong starburst and intense radiation from exploding young stars and a newly active supermassive black hole. After a few billion years, any remaining Milky Way would be largely featureless and unrecognizable.
While the team did not model a merger between the LMC (Large Magellanic Cloud) and the Milky Way in detail, they found that such a merger is likely to occur within the next 2 billion years.
In contrast, scientists believe that the sun’s eventual death will have a more significant impact on Earth than the predicted collision with Andromeda. The sun is expected to swell into a red giant that could engulf Mercury and Venus, potentially threatening Earth in about 5 billion years.
The new study highlights the complexities of predicting galaxy mergers and underscores the need for further research using data from upcoming space missions like the Gaia telescope.
Source: https://edition.cnn.com/2025/06/02/science/milky-way-andromeda-galaxy-collision