Topic
The Quran invites its readers to study sun, moon and stars as signs, but it is not a textbook of astronomy.
What it means
The Quran says that He made the sun a radiant lamp and the moon a light (10:5), that “each swims in an orbit” (21:33, 36:40), and that the moon has stations by which to count years (10:5). Medieval Muslim astronomers, including al-Biruni, understood such verses as inviting study and they measured the earth’s circumference and developed astronomical tables.
Often misunderstood as
That the Quran contains errors of astronomy, for example the sun setting in a muddy spring (18:86).
What the sources say
In the story of Dhu al-Qarnayn the verse says that he “found it setting in a spring of murky water”: that is, it appeared so to the traveller at the western sea. Commentators such as al-Tabari read it as appearance. The Quran’s own aim is stated: its signs are for “people who know” (10:5).