▲ 140 r/explainlikeimfive
ELI5: If the universe is constantly expanding, how do galaxies collide?
I remember hearing an analogy that the expanding universe is like putting a bunch of dots on a balloon and then inflating it—all of the dots grow farther apart. But then how do galaxies end up colliding? Does gravitational attraction outweigh the expansion?
u/2_wyckyd — 4 days ago