In first place we must observe that the universe is spherical. This is either because that figure is the most perfect, as not being articulated, but whole and complete in itself; or because it is the most capacious and therefore best suited for that which is to contain and preserve all things.

I can easily conceive, most Holy Father, that as soon as some people learn that in this book which I have written concerning the revolutions of the heavenly bodies, I ascribe certain motions to the Earth, they will cry out at once that I and my theory should be rejected.

At rest, however, in the middle of everything is the sun.

Therefore I would not have it unknown to Your Holiness, the the only thing which induced me to look for another way of reckoning the movements of the heavenly bodies was that I knew that mathematicians by no means agree in their investigation thereof.

The strongest affection and utmost zeal should, I think, promote the studies concerned with the most beautiful objects, most deserving to be known.

For what could be more beautiful than the heavens which contain all beautiful things.

Pouring forth its seas everywhere, then, the ocean envelops the earth and fills its deeper chasms.