Recent studies suggest the anticipated collision between the Milky Way and Andromeda galaxies, often called "Milkomeda," is less certain than previously thought. Astronomers have long predicted this galactic merger, but new findings indicate a reduced probability of it occurring within the next 4 to 5 billion years.
The initial prediction was based on the galaxies' trajectory towards each other at approximately 223,694 miles per hour. However, a new model considers the gravitational influence of smaller galaxies within the Local Group, including the Large Magellanic Cloud (LMC) and the Triangulum galaxy (M33).
Researchers conducted 100,000 simulations using data from the Hubble and Gaia space telescopes. The results show about a 50% chance of a collision between the Milky Way and Andromeda in the next 10 billion years, with only a 2% chance of collision in 4-5 billion years. The Gaia mission concluded its sky-scanning phase on January 15, 2025, and future data releases in 2026 and beyond will further refine these predictions.
While a Milky Way-Andromeda merger would dramatically alter both galaxies, the sun's eventual transformation into a red giant poses a more immediate threat to Earth. In approximately 5 billion years, the sun will expand, potentially engulfing Mercury, Venus, and possibly Earth.
It's also worth noting that a merger between the Milky Way and the LMC is more likely within 2 billion years. This event would significantly change the galaxy, impacting the central supermassive black hole.