. . . it is obvious that the earth moves. And because from the motion of the comets, of the air and of fire, we know by experience that the elements move, and [that] the moon [moves] less from the Orient to the Occident than Mercury or Venus, or the sun, and so on, it follows that the earth
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[paragraph continues] [considered as an element] moves less than all the others; yet [considered] as a star, it does not describe around the center or the pole a minimal circle, nor does the eighth sphere, or any other, describe the maximal, as has already been proved.
You have now to consider attentively what follows: just as the stars move around the conjectural poles of the eighth sphere, so also do the earth, the moon and the planets move in various ways and at [different] distances around a pole, which pole we have to conjecture as being [in the place] where you are accustomed to put the center. It follows therefrom that though the earth is, so to speak, the star which is nearer the central pole [than the others] it still moves, and yet does not describe in [its] motion the minimum circle, as has been shown supra. Moreover, neither the sun, nor the moon, nor any sphere—though to us it seems otherwise—can in [its] motion describe a true circle, because they do not move around a fixed base. Nowhere is there a true circle such that a truer one would not be possible, nor is [anything] ever at one time [exactly] as at another, neither does it move in a precisely equal [manner], nor does it describe an equally perfect circle, though we are not aware of it.