Proposing the earth rotates around the sun:
"How the earth is not in the centre of the circle of the sun, nor in the centre of the universe, but is in fact in the centre of its elements which accompany it and are united to it. And if one were to be upon the moon, then to the extent to which is together with the sun is above us, so far below it would our earth appear with the element of water, performing the same office as the moon does for us."
Proposing that the moon's light is reflected sunlight:
"The moon has no light of itself but so much of it as the sun sees, it illuminates. Of this illuminated part we see as much as faces us."