Was the universe infinitely small or was it just extremely or infinitely dense? Anyway, we don't actually know that, since we do not have a time machine. The t

Was the universe infinitely small or was it just extremely or infinitely dense? Anyway, we don't actually know that, since we do not have a time machine. The theory that the universe used to be much smaller is something we infer based on the snapshot we see today, just like we infer rotation based on the snapshot we see today. Either one could yet be proven wrong.