كُلٌّ فِي فَلَكٍ يَسْبَحُونَ (Each floating in an orbit - 21:33) The word فَلَک '' (falak) is used for circle or anything round. For this reason the word فَلَک '' (falak) is also used sometimes for sky. In this verse it means the orbits of the sun and the moon in which they revolve. The Qur'anic words do not specify the location of the orbits in the space but space research has now established that these orbits are located in the space much below the sky. This verse apparently indicates that the Sun also moves around an orbit. The scientists previously did not believe in the rotation of the Sun, but the most modern research has now accepted it.