Kepler

Kepler was the first person to correctly explain planetary motion, thereby, becoming founder of celestial mechanics and the first “natural laws” in the modern sense of 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.

All of those ray diagrams with erect and inverted arrows that are ubiquitous in text books were first created by Kepler in his books on optics. In addition:

• His book Stereometrica Doliorum formed the basis of integral calculus.
• First to explain that the tides are caused by the Moon.
• Tried to use stellar parallax caused by the Earth’s orbit to measure the distance to the stars an thereby derived a lower to their distances. This is the same principle as depth perception. Today this branch of research is called astrometry.
• 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

Kepler lived at the time of the Thirty-years war. The armies were marching and killings happening right outside his door in Prague, while he was inside unraveling the mysteries of the cosmos.  He himself was a peace maker, trying to build bridges between opposing sides and as a result was a man without refuge on either side. A wonderful example for all of us today. In addition, although he was the “Imperial Mathematician of the Holy Roman Emperor” he lived on the verge of poverty. His salary was always in arrears, to which many of us can relate when it comes to getting funded to do research. In fact he died (gave his life if you will) in the process of trying to collect on a debt owed him. Kepler also has a broad international aspect. Perhaps this is why there is no one single advocate for his recognition and where an international organization is most appropriate. He was born and educated in what is now Germany. His first employment was in what is now Austria. His most significant work was done in Prague and his last residence was in what is now Poland. In addition, one can also tie him to Denmark in that he worked with and used the astronomical data produced by Tycho Brahe from his observatory on Hven which was at the time part of Denmark but is now part of Sweden. All in all Kepler has had a major influence on astronomy, optics and the scientific method. We should recognize this and hold it up to our peers and to the world as an example as a scientist, as a peace maker and as one who triumphed in the face of adversity.