The man discovered the Planetary Motion. German Astronomer, Mathematician, Scientist, Writer. Life and work of German astronomer Johannes Kepler, famous for his three laws of planetary motion. A former assistant of Tycho Brahe, he advanced the Copernican Theory.
Johannes Kepler was a German astronomer and mathematician, a major figure in the 17th century scientific revolution. He is famous for this laws of planetary motion, and his works, a basis of Isaac Newton’s theory on gravitation.
Early Life of Johannes Kepler
Johannes Kepler (1571-1630) was born in a small Lutheran town of Weil der Stadt, in Germany, on December 27, 1571, son of Heinrich Kepler and Catharina Guldenmann. When he was three, his father joined mercenary soldiers and his mother followed his father to Flanders. He was left to the care of grandparents.
He did not have a happy childhood. He was sickly, having been born with defective eyesight. He began his education at the German Schreibschule in Leonberg but soon moved to Latin school, an influence to his later writings. At 13, he entered the Adelberg monastery school, and two years later enrolled at Maulbronn, a preparatory school for the Protestant University of Tübingen. In Sept 1588 he passed the university exam.
Kepler Becomes a Maths and Astronomy Teacher
At Tübingen his thought was profoundly influenced by Michael Maestlin, the professor of mathematics and astronomy. Kepler was an exemplary student and was noted by the school with a superior and magnificent mind. In August 1591, the 20-yr-old Kepler received his master’s degree and entered the theological course.
Halfway through his third and last year, an event happened that changed his life course forever. The teacher of mathematics and astronomy at the Lutheran school in the Styrian capital of Graz died, and he was chosen as the replacement leaving behind his career to be a Lutheran pastor.
Theology to Astronomy
He arrived in Graz, southern Austria in April 1594, with duty as a teacher and as provincial ‘mathematicus.’ He also produced an annual calendar of astrological forecasts that were impressive. In just over a year, he came up with his theory about the number, dimensions and motions of the planets in his pro-Copernican treatise Mysterium cosmographicum of 1596. He sent copies to various scholars including Galileo and the great Danish astronomer Tycho Brahe. He also married Barbara Mühleck, a daughter of a wealthy mill-owner.
In August 1600, the counter-Reformation took place in Graz. Kepler and other Protestants were expelled from the predominantly Catholic city. He decided to go to Prague with his family. On arrival, he found out that Brahe’s chief assistant had just died. Kepler was appointed in his place.
When Brahe was taken ill and died, Kepler was appointed to succeed as imperial mathematician. One of his duties was to complete Brahe’s work on Tabulae Rudolphinae, giving the positions of numerous stars and perpetual tables for calculating the positions of the planets on any date, past or future.
Kepler’s Laws of Planetary Motion
Kepler’s interest remained more in theoretical astronomy. Copernicus expounded the idea of the universe but believed that the orbits of the planets were in perfect circles. Kepler considered the possibility that it might be elliptic, with the sun at one focus, and he was right. His investigations are known as Kepler’s Laws of Planetary Motion.
- The Law of Ellipses
- The Law of Equal Areas
- The Law of Harmonies
His ideas appeared in his book, Astronomia nova, 1609. Brahe’s heirs tried to prevent his publication, including removing vital records of his observations, but Kepler managed to prevent this.
Later Years of Kepler
Kepler explained the idea of “The Star of Bethlehem” that led the Magi to then manger in Bethlehem where Jesus Christ was born.
Due to religious upheavals in Prague, Kepler left for Linz in 1612. He published two major works during his years there. The more important was Harmonicae mundi, published in 1619 towards the end of his life, a profound feeling he developed for the harmony of the universe, including the relationship of the cosmos and the individual, linked with his theological view of God the creator.