The Qur’an says the moon is a reflected light, since it derives its light from the sun. How could the Prophet have known this? It calls the moon ‘noor’ which here means reflected light.
“See ye not how Allah has created the seven heavens one above another, and made the moon a light (noor) in their midst, and made the sun as a lamp (siraaj)?” [Surah 71:15–16]
“It is He who made the sun radiant, and the moon a light, and determined phases for it-that you may know the number of years and the calculation. Allah did not create all this except with truth. He details the revelations for a people who know.” [Surah 10:5]