04
Night wrapping the day
يُكَوِّرُ اللَّيْلَ عَلَى النَّهَارِ
39:5
يُكَوِّرُ اللَّيْلَ عَلَى النَّهَارِ وَيُكَوِّرُ النَّهَارَ عَلَى اللَّيْلِ
He wraps the night over the day and wraps the day over the night.
21:33
وَهُوَ الَّذِي خَلَقَ اللَّيْلَ وَالنَّهَارَ وَالشَّمْسَ وَالْقَمَرَ ۖ كُلٌّ فِي فَلَكٍ يَسْبَحُونَ
And it is He who created the night and the day and the sun and the moon; each floating in an orbit.
The ayah in tafsir
Yukawwiru is the wrapping of a turban, coil upon coil. Al-Zamakhshari and others saw night and day succeeding as a winding. The image is of a round covering, not a flat sheet pulled from one edge. Kullun fi falakin yasbahun: each swims in a course. The verb is of a swimmer in a path, not a lamp pinned to a dome.
What later eyes saw
A sphere turning under a lamp makes night a wrap, not a wall. The terminator of light moves as a curve around the earth. The sun, earth, and moon each have a path. The Arabic of yukawwiru and yasbahun is the language of a rounded, moving sky — spoken in a desert that had no globe in every house.
Where we stop
The verse does not give orbital equations. Falak was already a celestial circuit in Arabic. The wonder is how plainly the wrap and the swimming are said.