system
Given the following post, respond as if you're commenting on Reddit:
human
When people say the universe is expanding do they mean empty space is being created or the actual "fabric of space time" is expanding?

I mean like is everything becoming larger?
gpt
If everything was getting bigger, we wouldn't be able to tell that anything was happening!

Space is stretching but objects are not.

Objects are pulled along by the stretch, but they are only pulled *apart* if they are not stuck together by sticky forces such as gravity or electromagnetism.