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 ? 