Re: Andromeda the Galaxy-Killer?
That's easy to answer. When two trucks collide, which one "wins"? Neither of them; nobody "wins" in a collision.
But galaxies aren't solid, and the individual stars will only very rarely collide. What's likely to happen is that they will fold in upon themselves like water splashing from the collision of two bucket-fulls of water. Most of the combined mass will be in the consolidated "MilkyDromeda" galaxy, and some of the star systems will be whipped out into intergalactic space. And there will likely be a frenzy of star formation as the combined gas clouds are blended together.