Colliding galaxies. Computer artwork of the Milky Way and Andromeda galaxies colliding, seen from an alien planet. Collisions between galaxies are fairly common. The collision distorts the shape of both galaxies, often casting off streamers of stars. Despite the fact that the galaxies may pass through each other, collisions between actual stars are exceedingly rare. The Andromeda?ａ¨Milky Way (Milkomedia) collision is a predicted galaxy collision that could possibly take place in approximately 3 billion years' time.