Where does the extra space come from as the universe expands? and if it’s just stretching, does that mean it somehow is getting thinned out?

Question

Where does the extra space come from as the universe expands? and if it’s just stretching, does that mean it somehow is getting thinned out?

In: 47

Answer 1

I think this is just a problem with how people talk about expansion. It’s useful to think about it as objects in the universe are getting farther apart as opposed to the universe expanding. If the things are just getting further apart the question of “what is the universe expanding into” goes away.