We’re not even really sure what we’re expanding into. It’s like a 4th spacial dimension.
You may be thinking that “expanding space” means that there are things flying away from each other. It’s not necessarily like that. Things are getting further apart because the space in between them is getting stretched. Over the course of time, I guess you could say, 1 meter ain’t what it used to be.
It’s like we’re all ants on the surface of a balloon that’s being blown up. It’s not just the different ants on the balloon that are moving apart. it’s that there’s “more balloon” between them. That’s an entirely different thing from peculiar motion, where an ant would start walking toward another one.
So your question can be restated as “If the balloon is being blown up, why can the ants hit each other?” and the answer is obvious…they’re walking toward one another.
I know I skipped a lot of technical stuff there but it’s hard to explain and I’m not even sure I understand it myself. I gave the meat of it…can someone else make the potatoes?