Johannes Kepler was a German astronomer who devoted his life to the study of planetary movements. It took him ten years to systematize his observations, but in 1619 they were published as Laws of Planetary Motion.
In addition to a gifted astronomer, Kepler was also a talented mathematician and an astrologer. He was born in 1571 in the small town of Weil der Stadt near Stuttgart and died in 1630 in Regensburg, Germany. He also the author of several important scientific works including Astronomia nova (1609), Harmonices Mundi (1619), and the series Epitome Astronomiae Copernicanae (1617-1621).
Johannes Kepler Facts
1. He invented the Keplerian telescope
In 1611, Johannes Kepler made a significant improvement on Galileo’s design of the traditional refracting telescope. Essentially, Kepler decided to use a convex instead of a concave lens as the telescope’s eyepiece. The main advantage of Kepler’s design is that it converges the beams of light emerging from the eyepiece.
The Keplerian telescope has a much wider field of vision and provides a significant eye relief. The only disadvantage is that the viewer is inverted. Still, the new design allows for greater magnifications, but to achieve them one needs a really big lens.
2. Kepler’s first job was a math teacher
Kepler’s remarkable scientific career had a humble start. An interesting fact about Johannes Kepler is that he was a math teacher in a seminary in the Austrian city of Graz. While teaching there, he developed an instrumental friendship with Prince Hans Ulrich von Eggenberg, who financed most of his later experiments and inventions.
Through his friendship with Prince Hans Ulrich, Keppler became the chief mathematician of Emperor Rudolf II. At that time, he also met Tycho Brahe in Prague and began a long and fruitful cooperation with him. Kepler used his religious education to support his scientific discoveries.
For example, he maintained that God had created the world according to a clever plan. In order to understand this divine plan, one needed to embrace the light of reason. Kepler’s philosophy became known as “celestial physics”. He believed that religion and science should be partners, not rivals.
3. Kepler’s father-in-law scorned him for his humble finances
In 1595, Kepler was introduced to the young and attractive widow Barbara Müller and immediately fell for her charm and intellect. She had inherited her late husband’s wealth, and her father, Jobst, was a respected miller.
Kepler, on the other hand, lived a humble life and made just enough money to keep the wolf from the door. Jobst did not believe that Kepler’s latest work, Mysterium, will bring him enough money to support his daughter and himself, let alone any children that might come later.
Johannes and Barbara’s engagement was about to fall apart, as Kepler went on a fundraising tour around Germany to support the publication of his book. Luckily, the mutual friends, that had made the match, convinced the young woman that far from sight does not always mean far from heart. The couple got married in 1597 and had three children, an interesting Johannes Kepler fact.
4. In 1613, Johannes Kepler married for a second time
Unfortunately, the marriage of Johannes Kepler and Barbara Müller was not meant to last. In 1611, death did part them, and Johannes became a bachelor again. He courted eleven different women over a two-year period and finally tied the knot with the 24-year-old Susanna Reuttinger. Their first three children died in infancy, but the next three survived through adolescence.
5. Kepler advocated the heliocentric model of the universe
While studying at the University of Tubingen, Johannes Kepler questioned the Ptolemaic system which dictated that Earth is the center of the universe. Over a series of disputes with his tutor Michael Maestlin, he defended the heliocentric model of the universe proposed by Nicolaus Copernicus. As Kepler earned his secondary education diploma at the Protestant Seminary of Maulbronn, he managed to draw in religious as well as scientific arguments in support of his views.
6. Kepler’s laws of planetary motion
An interesting fact about Johannes Kepler is that using the information collected by Tycho Brahe, he gradually developed his three laws of planetary motion. These postulates describe the motion of any system of planets around their star. Kepler’s 1609 work, Astronomia nova, describes the first two planetary laws.
The third law is the subject of Kepler’s 1619 work Harmonices Mundi. In a nutshell, his laws stipulate that planets’ orbits are ellipses and that each planet orbits the star at the center of its system at its own speed. The further a planet is from its sun, the slower it moves around it.
7. Kepler’s mother was charged with witchcraft
Johannes Kepler’s mother was accused of witchcraft by a certain Ursula Reingold. The issue reached the town’s council, and in 1620 Katharina was sent to prison to wait for her trial along with fifteen other women. The hearings turned out quite lengthy. Fortunately, Katharina’s son managed to convince the jury that they’d made a mistake and that his mother was not a witch. Unfortunately, Kepler’s mother died just one year after her acquittal.
8. Kepler’s grave is unknown to this day
Johannes Kepler passed away on November 15th, 1630 in Regensburg and was interred at the local cemetery. Unfortunately, the exact location of Kepler’s grave was lost for good during the Thirty Years’ War between Germany and Sweden.
9. The father of modern optics
Kepler is also famous for his monumental contributions to the development of optics, an interesting Johannes Kepler fact. He came up with the inverse-square law that deals with light intensity. Johannes Kepler also invented his own version of the refracting telescope, which helped him understand the structure and working of the eye. For these reasons, Kepler is considered the father of modern optics.
Johannes Kepler achieved international recognition as the leading astronomer and optician of his time, despite frequent persecutions and discrimination he had to endure because of his faith. Kepler was a Lutheran and while he was teaching in Graz, the town was hit by a wave of anti-Protestant moods that threatened to put an end to his budding career.
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