The squares of the periodic times are proportional to the cubes of the mean distances from the sun.

The Earth is round, and is inhabited on all sides, is insignificantly small, and is borne through the stars.

Truth is the daughter of time, and I feel no shame in being her midwife.

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

As soon as somebody demonstrates the art of flying, settlers from our species of man will not be lacking on the Moon and Jupiter. Who would have believed that a huge ocean could be crossed more peacefully and safely than the the narrow expanse of the Adriatic, the Baltic Sea or the English Channel? Given ships or sails adapted to the breezes of heaven, there will be those who will not shrink from even that vast expanse.

The squares of the periodic times are proportional to the cubes of the mean distances from the sun.

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