Johannes Kepler (1570–1630)

Astronomer and mathematician Johannes Kepler is best known for his discovery of the three laws of planetary motion, which once and for all removed the earth from its tyrannical reign as the center of the universe and sent it flying through the heavens. A contemporary of Galileo, Kepler and a handful of colleagues launched the Scientific Revolution, transforming the way humans perceived the nature and structure of the universe and ushered in a paradigm which exists to this day and informs all aspects of our lives.

But what makes Kepler unique was not only his unprecedented capacity to decipher reality but also his unwavering vision of the universe as a harmonic system of interconnected parts. It was from the notion of the universe being a geometric manifestation of the “mind of God” that all of his discoveries arose.

In addition to being an astronomer and a mathematician, Kepler also gained notoriety as an astrologer. And while he disparaged the use of astrology by charlatans, he refused to “throw out the baby with the bathwater” (a phrase he coined) in regard to understanding that planetary bodies affect human souls.

A devout Lutheran living during an era of violent religious conflict, Kepler refused any form of hatred and continued to perceive the universe as harmonious and magnificent despite the barbarity of man.

His life was characterized by ongoing struggles, losses and obstacles including the arrest of his mother for witchcraft. He died impoverished as the emperor refused to give him the salary he was owed and to this day has not gained the fame due him.

Appointed Imperial Mathematician of the Holy Roman Empire in 1601, Kepler is known for the following firsts (from the NASA website on Kepler):

  • First to correctly explain planetary motion, thereby, becoming founder of celestial mechanics and the first “natural laws” in the modern sense; being universal, verifiable, precise.
  • In his book Astronomia Pars Optica, for which he earned the title of founder of modern optics he was the:
    • First to investigate the formation of pictures with a pin hole camera
    • First to explain the process of vision by refraction within the eye
    • First to formulate eyeglass designing for nearsightedness and farsightedness
    • First to explain the use of both eyes for depth perception.
  • In his book Dioptrice (a term coined by Kepler and still used today) he was the:
    • First to describe: real, virtual, upright and inverted images and magnification
    • First to explain the principles of how a telescope works
    • First to discover and describe the properties of total internal reflection
    • His book Stereometrica Doliorum formed the basis of integral calculus.
  • First to explain that the tides are caused by the Moon (Galileo reproved him for this)
  • Tried to use stellar parallax caused by the Earth’s orbit to measure the distance to the stars; the same principle as depth perception. Today this branch of research is called astrometry.
  • First to suggest that the Sun rotates about its axis in Astronomia Nova
  • First to derive the birth year of Christ, that is now universally accepted
  • First to derive logarithms purely based on mathematics, independent of Napier’s tables published in 1614
  • He coined the word “satellite” in his pamphlet Narratio de Observatis a se quatuor Iovis sattelitibus erronibus


Dawn of a New Universe

by Rick Tarnas

It must have been a breathtaking experience to have been among those earliest scientific revolutionaries of the modern era, Copernicus and his immediate successors — Rheticus, Giese, Digges, Bruno, Maestlin, Kepler, Galileo — as they first began to grasp the stupendous truth of the heliocentric theory. The sense of cosmic upheaval and wonder would have been nearly inexpressible. A view of the Earth and its place in the universe that had governed the human mind virtually without question for untold thousands of years was now suddenly recognized to be a vast illusion...

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