So, influenced by these advisors and this hope, I have at length allowed my friends to publish the work, as they had long besought me to do.
Nicolaus Copernicus

The earth also is spherical, since it presses upon its center from every direction.
Nicolaus Copernicus

The earth together with its surrounding waters must in fact have such a shape as its shadow reveals, for it eclipses the moon with the arc of a perfect circle.
Nicolaus Copernicus

The massive bulk of the earth does indeed shrink to insignificance in comparison with the size of the heavens.
Nicolaus Copernicus

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.
Nicolaus Copernicus

Therefore, having obtained the opportunity from these sources, I too began to consider the mobility of the earth.
Nicolaus Copernicus

Therefore, in the course of the work I have followed this plan: I describe in the first book all the positions of the orbits together with the movements which I ascribe to the Earth, in order that this book might contain, as it were, the general scheme of the universe.
Nicolaus Copernicus

Therefore, when I considered this carefully, the contempt which I had to fear because of the novelty and apparent absurdity of my view, nearly induced me to abandon utterly the work I had begun.
Nicolaus Copernicus

Those things which I am saying now may be obscure, yet they will be made clearer in their proper place.
Nicolaus Copernicus

Those who know that the consensus of many centuries has sanctioned the conception that the earth remains at rest in the middle of the heavens as its center, would, I reflected, regard it as an insane pronouncement if I made the opposite assertion that the earth moves.
Nicolaus Copernicus

To know that we know what we know, and to know that we do not know what we do not know, that is true knowledge.
Nicolaus Copernicus

We regard it as a certainty that the earth, enclosed between poles, is bounded by a spherical surface.
Nicolaus Copernicus

Yet if anyone believes that the earth rotates, surely he will hold that its motion is natural, not violent.
Nicolaus Copernicus