1400 years ago people didn't know that the moon doesn't radiate visible light. Today we know that the moon can only reflect visible light. The sun is the only object in our solar system that radiates visible light.
[Quran 10.5] 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.
The sun radiates while the moon doesn't. No mistakes in the Quran.
How could an illiterate man who lived 1400 years ago have known what radiates and what doesn't?