Non-physics person here. I am trying to understand the expansion of space. I've read about the redshift of light and the balloon model (2 points on expanding balloon move away from each other).
The detection of the expanding universe depends on light. But what about matter? Does matter follow the expansion of space? Or does it "slide" so that space expands and whizzes by the matter, but the matter remains in the same distance and configuration relative to other matter?
I'm thinking of a very smooth disc of ice and hockey pucks on top. Suppose the disc somehow expands. Due to it being very smooth, the expansion doesn't move the pucks. They remain in the same relative positions but the disc underneath it expands and points on the ice whiz by the pucks.
Can someone explain how matter fits into space expansion and its detection?