The Gravity of Galaxies

When you have these two clusters moving, basically what happens is the galaxies just pass right by each other and they go out the other side. The gas on the other hand actually takes up space and so the gas from one cluster is going to hit the gas from the other cluster and you get a big collision of gas. So maybe stuff doesn't collide but doesn't the gravity get all messed up like when orbits and stuff be all kind of weird? Yeah, it does. It definitely gets slowed down, but it still goes through each other and will come out the otherside and be slowed down by it. Although actually it's initially accelerated as they start going together and then afterwards slowed down.