Johannes Kepler – Basic Laws of the Planetary Movement
The discovery of the three basic laws of the planetary movement made German astronomer Johannes Kepler one of the main founders of modern astronomy.
Johannes Kepler was born on December 27, 1571 in German Weil. He was the son of Heinrich and Kathrine Guldenmann Kepler. His father was a professional soldier. Although he was a Protestant, his father helped stifle Protestant uprisings in the countries of today’s Benelux. Kepler was allowed by his parents to watch the great comet in 1577 and the eclipse of the moon. Kepler was a hellish kid but also a great student. At 13 he started attending a religious school in Adelberg.
After graduating from the University of Tübingen in 1591, he became interested in astronomy, especially for the theories of Nikola Copernicus (1473-1543), who claimed that the Earth circles around the Sun. The University of Tübingen proposed Kepler as a “provincial mathematician” in Graz. He arrived there in 1594 and began to create a yearbook in which all major events were foreseen next year. His first year was a great success. There were two events that he predicted, an invasion of the Turks and a sharp winter, which confirmed his reputation. 1597. Kepler married Barbar Muehleck. Of their six children, only two, one boy and one girl, experienced an adult age.
Kepler sought the job of assistant to Tycho Brahe (1546-1601), astrologer and mathematician in Prague. Kepler came to his new appointment in 1600. When the next year Brahe died Kepler was named as his successor. His first job was to prepare for the publication of Brahe’s collection of astronomical works, which came out between 1601 and 1602. Kepler was also in charge of Brahe’s notes, which led him to the assumptions that led to the new theory of the orbits of all planets. The difference between his theory and Brahe’s data could only be explained if Mars’s orbit was not circular than elliptical (Kepler’s first law). This helped prove another of his claims. It is known as Kepler’s second law according to which a line that connects planets to the Sun crosses equal areas at the same time in its elliptical orbit.
Kepler published these laws in his lecture on the orbit of Mars, Astronomia Nova (1609). The two laws are clearly written in the contents of the book. Every careful reader had to be recognized enough to be aware of the new idea of such great significance. However, the Italian astronomer Galileo Galilei did not use the laws of his published works in his works – although they would help his defense of Copernican ideas.
1611. Rudolf II stepped down from the throne, and Kepler immediately looked for a new job. He received the job of provincial mathematician in Linz. By 1612, when he moved there with his two children, his wife and his favorite Frederick son were dead. Kepler’s 14th year in Linz marked his second marriage with Susan Reuttinger, and attempts to save his mother from being convicted as a witch. While in Linz, Kepler published two important works: His third law was published in Harmonica Mundi (1618). He claimed that the average distance of the planet from the Sun, raised to the third potential, divided by the time the planet should describe to the orbit, is the same for all planets. Kepler believed that nature followed numerical relationships since God created it by “weight, size, and number.” Kepler used the same idea when describing geometry. Kepler’s second work, Epitome Astronomiae Copernicanae (1618-21), proposed a physical explanation of the movement of the planets, that is, the “magnetic arms” that come from the Sun.
Kepler wandered through Europe for the last three years of his life. He was in Ulm when his Tabulae Rudolphinae (1628) was published, which not only contained positions of more than 200 stars more than Brahe’s published works but also had planetary tablets that became standard for the next century. Kepler died on November 15, 1630 in Regensburg.