solrize on Nostr: I'd like something about cosmology and maybe the size of the universe (not just the ...

I'd like something about cosmology and maybe the size of the universe (not just the observable part). Could it really be infinite? I've watched parts of Lenny Susskind's videos on GR and they are great, there's no need to redo them. But what I'd hoped to learn is what it means for spacetime to expand, such as during inflation. I guess the metric tensor changes, but not the way GR describes in response to mass. So any enlightenment would be appreciated!