وَ اِلَی السَّمَآءِ کَیۡفَ رُفِعَتْ ﴿ٝ۱۸﴾

And the heaven – how it has been raised?

Tafsir al-Qurtubi                                                                                                                                                                                      تفسیر القرطبی                                                    

أَيْ رُفِعَتْ عَنِ الْأَرْضِ بِلَا عَمَدٍ.

i.e. how it has been raised from the ground without a pillar.

Tafsir Qurtubi (Al-Jame’ Li Ahkaam al-Quran) Imam Shamsuddin Muhammad ibn Ahmad al-Qurtubi t D. 671 A.H.