it is he who made the sun a shining thing and the moon as a light and measured out for it stages that you might know the number of years and the reckoning. allah did not create this but in truth. he explains the ayat in detail for people who have knowledge.
هو الذي جعل الشمس ضياء والقمر نورا وقدره منازل لتعلموا عدد السنين والحساب ما خلق الله ذلك إلا بالحق يفصل الآيات لقوم يعلمون