Will Andromeda hit the Milky Way?
A head-on meeting, or a near miss? The answer changed in 2025.
How this site works. Every fact is in our own words and linked to its source, beside it. Where good sources disagree, we show each version in a “Sources differ” box.
Heading our way
Andromeda is getting about 110 km (70 miles) closer to us every second. Royal Observatory
As far back as 1912, astronomers realised Andromeda, then thought to be only a nebula, was heading our way. NASA, 2025
The 2012 prediction
In 2012 NASA said Hubble measurements predicted a head-on meeting with Andromeda in about four billion years. NASA, 2012
NASA’s illustrations showed Andromeda filling the night sky in 3.75 billion years, and the sky ablaze with new stars at 3.85 billion. NASA, 2012
In that picture the two would merge into a single elliptical galaxy about two billion years after the first encounter. NASA, 2012
NASA said the Sun would probably be flung into a new part of the galaxy, but Earth and the solar system would not be destroyed. NASA, 2012
Stars are so far apart that they would not hit each other. NASA, 2012
Triangulum would join in and might later merge with the pair; there was a small chance it would hit the Milky Way first. NASA, 2012
The 2025 study
In 2025 a new study using Hubble and Gaia data found only about a 50-50 chance of the two galaxies colliding in the next 10 billion years. NASA, 2025 It left only about a 2% chance of a head-on collision in just 4 to 5 billion years. NASA, 2025
The team considered 22 variables and ran 100,000 computer simulations reaching 10 billion years ahead. NASA, 2025
Lead author Till Sawala said the two could still go past each other. NASA, 2025
The Large Magellanic Cloud can change the Milky Way’s path and make a collision less likely. ESA/Hubble, 2025
Will they collide? Sources differ
- In 2012 NASA said Hubble measurements predicted a head-on meeting with Andromeda in about four billion years. NASA, 2012
- In 2025 a new study using Hubble and Gaia data found only about a 50-50 chance of the two galaxies colliding in the next 10 billion years. NASA, 2025
- It left only about a 2% chance of a head-on collision in just 4 to 5 billion years. NASA, 2025
The 2025 study used newer Hubble and Gaia data and included the uncertainties and the pull of other galaxies. NASA published both.
If it does happen
The merged galaxy has been unofficially nicknamed Milkomeda. Royal Observatory
Hubble’s deep views show galaxy collisions were more common in the past, when the universe was smaller. NASA, 2012
NASA points out that a warming Sun will make Earth uninhabitable in roughly a billion years, so Andromeda is the least of our cosmic worries. NASA, 2025
Our home galaxy’s side of the story is on milky-way.galaxies.im.
Our view: a coin toss in ten billion years is not worth losing sleep over. And even if it happens, the stars will slide past each other like ships in a very large, very dark sea.
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