We ought not to ask why the human mind troubles to fathom the secrets of the universe. The diversity of the phenomena of nature is so great, and the treasures hidden in the skies so rich, precisely in order that the human mind shall never be lacking in fresh nourishment.

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

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

I much prefer the sharpest criticism of a single intelligent man to the thoughtless approval of the masses.

Sky-bound was the mind, Earth-bound the body rests

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.

…   not my own opinion, but my wife’s: Yesterday, when weary with writing, I was called to supper, and a salad I had asked for was set before me. ‘It seems then,’ I said, ‘if pewter dishes, leaves of lettuce, grains of salt, drops of water, vinegar, oil and slices of eggs had been flying about in the air for all eternity, it might at last happen by chance that there would come a salad.’ ‘Yes,’ responded my lovely, ‘but not so nice as this one of mine.

Now because 18 months ago the first dawn, 3 months ago broad daylight but a very few days ago the full sun of the most highly remarkable spectacle has risen — nothing holds me back. I can give myself up to the sacred frenzy, I can have the insolence to make a full confession to mortal men that I have stolen the golden vessel of the Egyptians to make from them a tabernacle for my God far from the confines of the land of Egypt. If you forgive me I shall rejoice; if you are angry, I shall bear it; I am indeed casting the die and writing the book, either for my contemporaries or for posterity to read, it matters not which: let the book await its reader for a hundred years; God himself has waited six thousand years for his work to be seen.

The orbit of every planet is an ellipse with the sun at one of the two foci.