Astronomers long expected the Milky Way and Andromeda to collide in about 4.5 billion years — but a 2025 study in Nature Astronomy, using Hubble and Gaia data, estimated only a roughly 50–50 chance of
Recent scientific studies have produced conflicting probabilities regarding the future collision of the Milky Way and Andromeda galaxies. While a 2025 study suggested even odds, a 2026 follow-up increased the estimated probability of a merger to 90 percent.
Why it matters
Refining these astronomical models helps scientists better understand galactic evolution and the long-term dynamics of our local universe.
The 2025 estimate depended on uncertain motions and neighbouring galaxies. A 2026 follow-up put the merger probability higher, showing why the forecast remains sensitive to the measurements.
Published September 7, 2026 · How we edit
The Milky Way’s expected collision with Andromeda became considerably less certain in June 2025. In a Nature Astronomy paper led by Till Sawala , researchers using Hubble and Gaia observations estimated roughly even odds that the two galaxies would merge within the next ten billion years.
That estimate needs a date attached. A separate study published in April 2026 subsequently raised the merger probability to about 90 per cent in its preferred model. The 2025 finding is worth taking seriously, but it should not be read as the final word.
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