I demonstrate by means of philosophy that the earth is round, and is inhabited on all sides; that it is insignificantly small, and is borne through the stars.

I used to measure the skies, now I measure the shadows of Earth.
Although my mind was sky-bound, the shadow of my body lies here.

[Epitaph he composed for himself a few months before he died]

If there is anything that can bind the mind of man to this dreary exile of our earthly home and can reconcile us with our fate so that one can enjoy living,—then it is verily the enjoyment of the mathematical sciences and astronomy.

You can't take sides when you know the earth is round.

The diversity of the phenomena of nature is so great, and the treasures hidden in the heavens so rich, precisely in order that the human mind shall never be lacking in fresh nourishment.

Discover the force of the skies O Men: once recognised it can be put to use.