Asalamualaikum
I was mooching around the internet and found another old tafsir stating that Surah 51:47 means expanding.
You will have to check the arabic
Here is one of the available interpretations offered by one of the most respected Muslim scholars Al-Baidawi who lived in the 14th century. His interpretation (tafsir) is one of 9 that are most respected by Muslims.
وَٱلسَّمَاءَ بَنَيْنَـٰهَا بِأَيْدٍ, بقوة. { وَإِنَّا لَمُوسِعُونَ } لقادرون من الوسع بمعنى الطاقة والموسع القادر على الإنفاق. أو {
لَمُوسِعُونَ } السماء أو ما بينها وبين الأرض أو الرزق.
The translation of the part highlighted in blue reads,
"{expanding} means expanding the sky (heavens) or what is between it and the earth or the (expanding of) sustenance."
http://www.altafsir.com/Tafasir.asp?...&UserProfile=0If the translation is correct it should be added to the site insha'Allah
