system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When the Milky Way and Andromeda collide, what will happen to their supermassive black holes at their centers?
gpt
The chances of them colliding with each other during the initial collision is extremely remote.

It's moderately likely that they will absorb one or more stars during the collision before they, like 99.99% of the other stars in each galaxy, pass out the other side unscathed.

The courses of all the stars and massive objects in the Milky Way and Andromeda galaxies will certainly be distorted heavily and the shape of each galaxy disrupted as they slowly ocillate between 2 distinct galaxies and a single amorphous galaxy. Over many millions of years the 2 galaxies will eventually completely merge and it's likely the 2 black holes will one day merge after they eventually come within an very small distance (~1 light year which is tiny on a galactic scale) but there is no certainty that the 2 will end up in the exact same region until many millions, even hundreds of millions of years have passed.