So it does happen on a small local scale though. It happens on ALL scales.
But everything is expanding from everything. Meaning the observer is always centred of the expansion. This is because volume is constant. The rasins themselves do expand, but locally it’s such a small scale (10^-23 m/s for our solar system).
This also works for how we understand the change in density. Volume is constant, but we’ve gone from infinitely dense to almost nothing.
So it does happen on a small local scale though. It happens on ALL scales.
But everything is expanding from everything. Meaning the observer is always centred of the expansion. This is because volume is constant. The rasins themselves do expand, but locally it’s such a small scale (10^-23 m/s for our solar system).
This also works for how we understand the change in density. Volume is constant, but we’ve gone from infinitely dense to almost nothing.