(Al-Vaqia) 56 : 76
وَإِنَّهُ لَقَسَمٌ لَوْ تَعْلَمُونَ عَظِيمٌ
And it is a great swearing, if you know.
In this period, when it is understood about the wideness of the universe having many groups of stars, including billions of stars, which are many times bigger than the earth, it is more understandable that ‘it is a great swearing’ mentioned in the verse. See explanation 3: 190-191; 51: 47; and 53: 1.