Johannes Kepler was a German astronomer, mathematician, and astrologer. In the 17th century, he served as a key figure during the scientific revolution. Kepler came up with the laws of planetary motion and wrote works that provided the foundation for Newton’s theory of universal gravitation.
The name Kepler is one of the most important in the scientific world. He was a mathematics teacher at a seminary school in Graz. There, he became an associate of Prince Hans Ulrich von Eggenberg. He also worked as an assistant to astronomer Tycho Brahe and mathematician Emperor Rudolf II.
He lived in an era where there was no clear distinction between astronomy and astrology. But there was a strong division between astronomy and physics. The former was a branch of mathematics within the liberal arts, while the latter was a branch of natural philosophy.
Yes, Kepler did incorporate religious arguments and reasoning into his work. He got motivated by the religious conviction and belief that God had created the world. He described his astronomy as “celestical physics”.
Today, we will talk about some of the lesser known facts about his life and career. Besides his Kepler’s laws, he is the founder of modern optics. He discovered eyeglasses for near eye sightedness and far eye sightedness. Kepler also invented an upgraded version of refracting telescope, naming it Keplerrian telescope.
What is he famous for?
Before we move into the lesser known facts about Johannes Kepler, let’s mention his most notable work. There are three Kepler’s laws of planetary motion.
– Every planet’s orbit is an ellipse with the Sun at a focus
– A line joining the sun and a planet sweeps out equal areas in equal times
– The square of a planet’s orbital period is proportional to the cube of the semi-major axis of its orbit
Today, we use the third law most often. And when we talk about Kepler’s law, we talk about his third law of planetary motion.
Tycho Brahe’s meticulous observations of the stars and planets provided Keplre with the dataset to test his hypotheses about planetary motion. Kepler observed the position of Mars in the Uraniborg night sky, serving as the primary source of hard data to test his three laws.
These laws have an important place in history of astronomy, cosmology, and science in general. Thanks to these laws, we had the revolution that moved the center of the universe from the Earth to the Sun. The laws laid the foundation for the unification of heaven and earth. One century later, Newton used these laws to come up with his universal law of gravitation.
That being said, let’s take a look at a couple of lesser-known facts about Johannes Kepler.
Born prematurely
Born in December 1571 on December 27, he came to this world earlier than anticipated. He had three siblings, two brothers and a siter. He was born prematurely and suffered from small pox at a very early age. This disease left him with crippled hands and weak eyesight.
He was a feeble child with weak vision.
His mother introduced him to astronomy
By the time he came to this world, his family became poor. At the age of six, he started his education at school. But he had to leave school early on and earn money for the family by working as a waiter.
During the nights, his mother took him out to show him interesting things in the skies. Some of those include the Great Comet of 1577 and a lunar eclipse. That sparked his interest in astronomy.
The first defense of the heliocentric model of Copernicus
Kepler studied at the University of Tubingen. There, Michael Meastlin taught mathematics, one of the most talented astronomers in Germany. The university lectures followed the Ptolemaic system, placing the earth at the center of the universe.
But Michael accepted the heliocentric Copernican view. He corresponded with Kepler and played a key role in Johannes believing in that system.
In a student disputation, Kepler defended the Copernican view from a theoretical and religious perspective. In 1596, he wrote the first published defense of the Copernican system, Mysterium Cosmographicum.
He got married twice and fathered many children
In 1595, he started courting Barbara Muller, a 23-year-old widow. Her father opposed the match as Kepler had no money. However, they got married in April 1597. Their first two children died in infancy, and they finally got their daughter and two sons.
They had an unpleasant marriage. And following her death in 1611, he considered 11 different matches over a period of two years. He returned to the fifth match, marrying 24-year-old Susanna Reuttinger in October 1613.
Their first three children died in childhood, but the next three survived.
Serving as Imperial Mathematician to the Holy Roman Emperor
In February 1600, Tycho Brahe invited Kepler to be his assistant, but the two didn’t get along. But each knew the value of the other. Tycho died in October 1601, and two days later Kepler got appointed as his successor as Imperial Mathematician.
He served the role in the post under Emperor Rudolf II and his two successors, Matthias and Ferdinand II.
Kepler believed his laws reflect God’s design
Johannes Kepler incorporated a lot of religious views into his laws. He considered his three laws as celestial harmonies. Kepler believed they reflect God’s design.
Kepler believed that God had created the world according to an intelligible plan. In his work Harmonices Mundi, he found harmonies in nature to claim that the Earth has a soul because it is subjected to astrological harmony.
While finding these harmonies, Kepler discovered his third law of planetary motion.
His mother was accused for witchcraft
His brother Christoph got involved in a financial dispute with a woman by the name Ursula Reingold. She claimed that Kepler’s mother Katharina had made her sick with an evil brew.
The dispute escalated, and as a result, they accused Katharina of witchcraft. The town people claimed she had been instructed in magic by an aunt, who has been burned for sorcery. The witch hunt resulted with 15 women getting accused and imprisoned for witchcraft.
