In verse 40, it was said: وَكُلٌّ فِي فَلَكٍ يَسْبَحُونَ (And each one is floating in an orbit - 40). Literally, the word: فَلَک (falak) does not mean the sky. Instead, it means the orbit in which some star moves. This verse has also appeared earlier in Surah Al-Anbiya' (21:33). It tells us that the moon is not contained within some sky as presumed by the astronomical theory of Ptolemy. Instead, it moves in a particular orbit in the space lower than it. Then, there are recent investigations as well as the human access to the moon that have made it certain.