>>18648201From a galactic perspective that'll be quite the funfest. (If/when Andromeda collides with the Milky Way, though, the Sun will have been long gone.)
Individual solar systems are pretty far apart, so most effects would be largely ignored on the planetary scale; the chance of actual stars, planets, etc. colliding would be very small.
The black holes at the galactic core would pose a more interesting problem. That I've got no fucking idea what would go on.
