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

The expansion of space isn’t really accurately represented when we try to conceptualize it as an expanding 2D plane or even an expanding 3D bubble. It doesn’t get thinned out and “extra space” isn’t being added in. Looking at the functions we use to model the expansion gives you a more intuitive understanding than trying to visually conceptualize it.