The stars that retreat

Quran 81:15:

So I swear by the retreating stars 

The following excerpt is taken from “The Holy Quran in Today’s English” under the commentary of the above verse note # 2533:

The scholars differ as to what is being referenced here with the Arabic word khunnas or withdrawers, with some saying it means stars and others asserting it means planets.  (I have chosen a compromise rendering.) The planets and stars in the night sky have a variety of observable motions based upon the time of year, the position of the earth, the speed of the individual planet or star relative to the earth’s orbital speed around the sun, etc.  Sometimes they seem to follow an east to west motion across the sky; other times they decline in their orbit, and still other times they are hidden behind the path of other objects.  These erratic-seeming motions are explained in the scientific principle known as Kepler’s Second Law of Planetary Motion.

Emerick, Yahiya. The Meaning of the Holy Qur’an in Today’s English (p. 827). Unknown. Kindle Edition.