Verses 5-6 of Chapter 10:

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. Verily, in the alternation of the night and the day and in all that Allah has created in the heavens and the earth are Ayat for those who have Taqwa (fear for God).