وبنينا فوقكم سبعا شدادا (78:12) بالانجليزي

(78:12) and built above you seven strong firmaments, *9

Tafseer Abu-al-A'la Maududi

Page 582 English Traditional

*9) "Strong" in the sense that their boundaries are so strongly fortified that no change whatever occurs in them, nor does any of the countless stars and planets in the heavens, violating these boundaries, collide with the other, nor falls down to the earth. (For further explanation, see E.N. 34 of Al-Baqarah, E.N. 2 of Ar Ra'd, E.N.'s 8, 12 of Al-Hijr, E.N. 15 of AI-Mu'minun, E.N. 13 of Luqman, E.N. 37 of Ya Sin, E.N.'s 5, 6 of As-Saaffat, E.N. 90 of Al-Mu'min, E.N.'s 7, 8 of Surah Qaf).