Johannes Kepler
Kepler, Johannes
Johannes Kepler (1571-1630), born in Weil der Stadt, Württemburg, the Holy Roman Empire of German Nationality. Kepler eventually moved to Prague during the Thirty-Years War to escape religious persecution. While in Prague, he worked with Tycho Brahe, a renowned Danish astronomer. After Brahe passed away, Kepler followed in his footsteps; using Brahe’s collection of data, Kepler was the first to correctly explain planetary motion. Kepler’s three laws of planetary motion that bear his name were published in 1609 and 1619. Kepler described how the orbits of the planets were not the circles described by Aristotle and assumed implicitly by Copernicus, but were instead "flattened circles", or ellipses. Kepler also made important contributions to optics, including the first explanation of the human vision process by refraction within the eye, the first eyeglass design for nearsightedness and farsightedness, the first description of depth perception, and the first detailed explanation of the principles of how a telescope works. Kepler also theorized that the tides were caused by the Earth's moon, and that the Sun rotates about its axis.
Further Reading
Johannes Kepler: His Life, His Laws and Times (NASA's Kepler Mission Website)
Kepler Biography (University of St. Andrews, Scotland, School of Mathematics and Statistics)
NASA's Kepler Mission: a search for habitable planets
