Commentary Par II 30

Beatrice makes plain what we have probably fathomed: Dante is in the sphere of the Moon, within the body of this 'star' itself.  Dante's terms for the heavenly bodies are, from a modern point of view, both inconsistent and, at times, different from ours, as the reader has already probably noted.  (Later on in this canto he will refer to the Moon as a planet [pianeto, verse 76] and not, as here, a 'star.'  He uses the terms interchangeably; for us the Moon is neither of the above.)