100,000 computer simulations reveal Milky Way’s fate—and it might not be what we thought.
For over a century, the prevailing understanding of our Milky Way galaxy suggested that it is on a collision course with the Andromeda galaxy, expected to merge into a larger entity in approximately 5 billion years. However, a new study published in the journal Nature Astronomy challenges this long-held view, presenting a scenario where the likelihood of a collision is much less certain. The authors of the study estimate that there is about a 50 percent chance the two galaxies could avoid merging altogether over the next 10 billion years.
The Milky Way and Andromeda (M31) belong to the Local Group (LG), which includes other smaller galaxies and dark matter, consistent with current cosmological theories. The researchers noted that both galaxies possess remnants from previous mergers and interactions with other galactic bodies.
According to the study, “Predicting future mergers requires knowledge about the present coordinates, velocities, and masses of the systems partaking in the interaction.” Key factors include not only the gravitational attraction between the galaxies but also the influence of dynamical friction, which becomes significant as galaxies approach one another, leading to a decline in their orbital paths.
This analysis utilized data from the Hubble Space Telescope and the European Space Agency’s Gaia space telescope to run 100,000 Monte Carlo simulations, examining not just the Milky Way and Andromeda but the entire Local Group system. The findings suggested a balanced outcome, with about a 50 percent probability of collision within the next 10 billion years and a 2 percent chance within the next 4 to 5 billion years. The authors concluded that, based on the latest data, the future of our galaxy remains unpredictable.
