6 So also they erred who believed that the sun is a god. For we see that it is moved by the compulsion of another, and revolves and makes its journey, and proceeds from sign to sign, rising and setting every day, so as to give warmth for the growth of plants and trees, and to bring forth into the air where with it (sunlight) is mingled every growing thing which is upon the earth. And to it there belongs by comparison a part in common with the rest of the stars in its course; and though it is one in its nature it is associated with many parts for the supply of the needs of men; and that not according to its own will but rather according to the will of him who rules it. And hence it is impossible that the sun should be a god, but the work of God; and in like manner also the moon and the stars.
Source: The Apology (New Advent)