A son’s orbit and a mother’s trial

In “Galileo’s Daughter,” Dava Sobel pioneered a genre -- the examination of a Renaissance scientist through the prism of the scientist’s little-known relative. The relative in Sobel’s book, a biography of 17th century Italian astronomer Galileo Galilei, was Suor Maria Celeste, the scientist’s illegitimate daughter, a cloistered nun who came alive in Sobel’s translations of her letters to her father. Maria Celeste also supported Galileo’s science. After the Roman Catholic Church imposed a penance on Galileo for endorsing a heliocentric solar system, she assumed the burden of that penance -- reciting his prescribed prayers so he would be free to work.

In “Kepler’s Witch,” James A. Connor, a former Jesuit and professor of English at Kean University in New Jersey, uses the little-known-relative approach for a biography of Johannes Kepler, the German mathematician, astrophysicist and contemporary of Galileo. The “witch” of the title is Kepler’s mother, who was tried and convicted of heresy in 1621.

Like Sobel, Connor builds his narrative from new translations of obscure material, including Kepler’s letters and journal entries, as well as documents from his mother’s trial. But unlike Sobel, he does not tell a happy story. In contrast with Maria Celeste, Katharina Kepler does not come alive in her letters; she was illiterate. “Her formidable intelligence,” Connor observes, was “stuffed back inside of her ... with no way out.”

Nor was she a boon to Kepler’s career. Stubborn and self-destructive, her legal flare-ups took Kepler away from his work, often when he most needed to concentrate. What is more, she probably caused the ailments that her critics attributed to witchcraft. A dabbler in herbal medicine, she rarely cleaned her mixing bowl. “Who knows what kinds of bacteria were growing in there?” Connor writes.

If Katharina was obnoxious, however, her accuser in the witchcraft trial, Ursula Reinbold, a former prostitute and vicious gossip, was equally repellent. As was the town magistrate, who, egged on by Reinbold, apprehended and tyrannized Katharina while he was drunk. Their lurid and distasteful story, however, is not entirely gratuitous. It makes the book’s tough technical passages and theological minutia fun to read. Just as Kepler sought refuge from the tumult of 17th century political conflicts in what Connor terms the “hidden mathematical harmonies of the universe,” so too the reader takes sanctuary from Kepler’s squalid family in Kepler’s orderly thought.

Kepler is best known for his three laws of planetary motion. The first, the “law of ellipses,” says that each planet follows an elliptical orbit with the sun at one focus of the ellipse. (Astronomers had previously believed orbits to be circular.) The second, the “law of equal areas,” says “the radius vector joining a planet and the sun sweeps out an equal area over an equal period of time.” In other words, if you drew a line from the sun to a planet, as the planet moves along its elliptical orbit, it would, over time, “sweep out” a wedge shape. And while the wedge that swept out in, say, three minutes would look one way if the planet were far from the sun and another way if the planet were close to it, the area of all wedges formed in three minutes would be the same. The third law addresses the overall solar system: It provides a formula to describe the relationship between the orbital periods of planets and their distances from the sun. Kepler is also known for his breakthroughs in optics; he was the first to explain how a telescope works.

Although Connor does an adequate job of explaining Kepler’s science, he is more articulate about Kepler’s religion, specifically his quest for the “numinous” -- an “encounter beyond words,” in which people “are caught up in the folds of God.” Kepler seeks this through the contemplation of celestial mechanics: “that marvelous harmony, that order to things, like the order of music that heals the soul and harrows sin from the world.”

During the Counter-Reformation, however, such theological originality was frowned upon by the Lutheran Church, to which Kepler belonged, as well as by the Roman Catholic Church, which persecuted Protestants and encouraged him to convert. Yet far from professing convenient beliefs, he followed his conscience -- leading, ultimately, to his excommunication by the Lutherans.

Kepler’s professional relationships also were strained by his commitment to the truth. At the court of Holy Roman Emperor Rudolf II in Prague, he worked closely with Tycho Brahe, the Danish optical astronomer. Yet the two disagreed on the structure of the solar system. Kepler believed the sun was at the system’s center; Tycho believed the planets circled the sun, but the sun circled the Earth. After the Danish astronomer’s death and against the wishes of his surviving family, Kepler used Tycho’s data to discredit Tycho’s system.

At first I thought Connor’s focus on Kepler’s mother was pure sensationalism -- the equivalent of viewing Jimmy Carter through the lens of his reprobate brother, Billy. But the 17th century was a rough, bloody time in which ignorance, corruption and religious hatred often trumped knowledge, ethical behavior and religious tolerance. Genius was a scant buffer against such terrible storms. By showing Kepler’s inability to shield his own mother, Connor drives this point forcefully home. *