system
Given the following post, respond as if you're commenting on Reddit:
human
"Space is expanding"; is it also fair to say instead "matter is shrinking"? Is this perspective any different?
gpt
The short answer is no. That wouldn't work.

When space expands, the distance between all points in space increases.

Particles of matter are, themselves, already points, and consequently have no size which could decrease.

If you were to dilate everything so that their sizes decreased, then the distance across a ruler would be unchanging relative to the ruler's distance to a distant object like a galaxy. That's not what we observe. Relative to the length of a ruler, distant objects are getting further away.