Are the galaxies in the universe moving through space ?   No , the galaxies sit more or less passively in the space around them . But not too much . As the space between galaxies expands , it carries the galaxies further apart - like raisins in an expanding dough .   But I heard that our Milky way galaxy may one day collide with a neighboring galaxy . If galaxies are moving apart from each other , how can they collide ?   Well , the universe is a chaotic place , and the gravity from one galaxy , or from a group of galaxies , may disturb the motion of its near neighbors , causing them to collide . However , on average , when you compare two large enough chunks of space , the galaxies in one are moving away from the galaxies in the other .   Wow , you're really informative . Thanks a lot .   You're welcome . 