Tycho and Kepler (22 page)

When
Tycho took up his pen in 1587 to write the new material for his book about the comet, he was still unaware that Bär had plagiarized his model. His unease as he remembered Bär’s visit was nevertheless sufficient motivation for publishing his planetary system as quickly as possible. He ended his manuscript with great flair, describing his model, much refined during ten years of research on Hven.
All the planets revolved around the Sun, while the Sun revolved around Earth. The orbit of Mars intersected the orbit of the Sun, which was quite possible, Tycho insisted, because the orbits
were
not
spheres made of crystal. But Tycho’s iconoclasm went further than shattering the “crystalline spheres”—about which astronomers had harbored some doubts even as early as Ptolemy. He had concluded that
the comet’s velocity was irregular as it moved around the Sun, defying another ancient assumption, that celestial motion must be uniform. He even moved beyond Aristotle, Ptolemy, and Copernicus by suggesting that its orbit was egg-shaped, not circular as he had previously thought and as earlier astronomy required all orbits to be.

Tycho finished the book with a critical overview of all other
literature about the comet, a feature that would become a standard part of any scholarly monograph but was revolutionary for his time. Tycho’s book became a model for future scientific publications and the definitive book about the comet of 1577.

Mysteriously, Tycho said nothing in his book about having observed the diurnal parallax of Mars in 1587.

During the years when Tycho was planning
and executing his assault on Mars’s parallax, he was also involved in a related campaign to ensure and link the futures of his family and his work at Uraniborg. Tycho was nearing forty. By all outward signs he was still at the height of his physical and mental powers, but in the sixteenth century a man could not expect good health to last much beyond forty. The work he had begun, he felt, was
too important to be allowed to expire when he did. Accordingly, the dedication stone of Stjerneborg was inscribed with words prophesying that posterity would preserve this observatory for the advancement of astronomy, the glory of God, and the honor of Denmark. The portrait on the wall inside representing “Tychonides,” the future master astronomer who would carry on that work, was a blatant claim
that this astronomer would be none other than one of Tycho’s children. The symbolism and rhetoric were in place. The practicalities were more problematical. The future of Tycho’s sons and daughters and of his observatory were, in fact, precarious. Both Danish law and tradition
dictated
that because of their lowborn mother, Tycho’s children could not inherit the fief of Hven.

Kirsten and Tycho
had found ways to adjust to the problems created by her status. She was mistress of the household at Uraniborg and probably enjoyed as much respect and deference from Tycho’s assistants and servants as any noble lady would have. However, when Tycho attended the weddings, christenings, and funerals of aristocrats, he always went without her. When noble and royal visitors, such as Queen Sophie herself,
and James VI of Scotland, visited Uraniborg, Tycho’s sister Sophie served as hostess for the splendid banquets and festivities. Tycho’s relatives and Kirsten’s never mingled.

In June 1580 there had been an ominous new royal ordinance condemning common-law marriages as “an evil, scandalous life
⁵
with mistresses and loose women, whom [men] keep in their houses and with whom they openly associate,
brazenly and completely without shame, just as if they were their good wives.” The ordinance demanded that the clergy separate such couples and, if the couple resisted, deny them the sacraments and rites of the church.

Since all over Denmark pastors of parish churches owed their jobs to the lords of their manors, it was difficult to enforce the ordinance among the nobility. Tycho did stop
going to Communion—perhaps so as to deny the church the opportunity of banning him, or to make things less awkward for the pastor of St. Ibb’s. But he and Kirsten went on living as before. Other noblemen married their non-noble “wives,” and this provoked yet another royal ordinance, in June 1582, which reinforced the ban on children of such marriages inheriting nobility, land, estate, coat of arms,
or family name. The same ordinance, however, made it clear that a father could give money and personal property to these children while he was still alive, which they could keep on his death.

Even before the two royal ordinances, Tycho had begun to contrive a way to link the future of Uraniborg and the future of his children. Kirsten had given birth to a son at Uraniborg in 1581, and they
had
named him Tycho. A daughter, Cecilie, was born in 1582, and a second son, Georg, in 1583. In 1584 Tycho’s old preceptor, Anders Vedel, came for a visit, and the two men wrote a draft for a royal patent granting the island to Tycho and his male issue, provided they use it and its facilities for the pursuit of mathematical studies. To grant a fief in perpetuity was rare, to grant it to commoners
was unheard of, but it was not unheard of for commoners to hold the position of university professor or head of a secularized monastery with an income derived from a landed benefice, in some ways the equivalent of a fief. Tycho and Vedel, in drafting the patent, implied that Uraniborg had more in common with a university than with a traditional fief, and that the directorship of Uraniborg was
like a professorship or headship.

Tycho and Vedel had judged the situation well. When Tycho presented the proposal to Frederick, the king readily approved it, with the queen as witness. Unfortunately, nothing was written down, and no actual patent was issued.

King Frederick’s ill health had been a source of concern for more than a year, and he died on April 4, 1588, not long after he had
given verbal approval to Tycho’s proposal. Frederick’s son Christian was still a child, and a regency council assumed the government of Denmark. In spite of the inevitable atmosphere of upheaval, Tycho had no reason for concern, for the new government was packed with his friends, relatives, and allies. In August 1588 he presented his plan for the future of Hven to the Regency Council, which not
only issued the patent with a glowing statement of its desire to perpetuate the astronomical work on Hven far into the future, but also endowed Uraniborg with ecclesiastical incomes from canonries and other church offices, implying it could be headed by a commoner. Best of all, the patent laid down an order of succession for Uraniborg, giving preference to Tycho’s sons or sons-in-law. It referred
to these descendants as “Tycho Brahe’s own”—the only official recognition that Tycho had children.

As favorable as this outcome was, Tycho did not allow matters to rest there. To avoid any confusion either in that time of political turmoil or later when the young king came of age, he obtained a patent signed by the entire Rigsraad and the Regency Council. He also persuaded Queen Sophie to
put in writing that she could remember her late husband Frederick II stating his intention that one of Tycho Brahe’s own children would become head of the observatory. It seemed that Uraniborg would, as the inscription at Stjerneborg prophesied and Tycho had hoped for so long, become a permanent research institution under the directorship of his heirs.

fn1
Recall that the closer one holds
a finger to one’s eyes, the larger the shift against the background appears to be.

fn2
Owen Gingerich and James Voelkel are two modern-day experts on the life and work of Tycho Brahe and the astronomy of his era. They have studied Tycho’s journals and laid out in all its paradoxical intricacy the chronology of Tycho’s campaign to find Mars’s parallax. The reconstruction of the activity that
took place on the night of March 10 comes from their article “Tycho Brahe’s Copernican Campaign.”

10

T
HE
U
NDERMINING OF
H
UMAN
E
NDEAVOR

1589–1591

IN 1589 TYCHO
Brahe was at the peak of his career, renowned in scholarly circles throughout Europe and approaching his forty-third birthday. Johannes Kepler was seventeen years old and waiting for an opening at the Stift in Tübingen. Finally, in September, space was available. Already in possession of a baccalaureate degree, he set off
for university. Traveling through the forests of the Schönbuch, he carried with him only books and a few personal possessions, a stark contrast to the accoutrements that a wealthy young man like Tycho would have taken along.

The castle of Hohentübingen sat like a mother hen over the university town that huddled beneath it in the valley of the Neckar River. Narrow streets with closely packed
high-gabled houses led from the riverbanks to the foot of the castle promontory. Kepler threaded his way through these streets and found the Stift, where he would study and have his lodging. The buildings were old, for this had been an Augustinian monastery before the Reformation. In Kepler’s time it was a seminary for scholars who were “children of poor,
¹
pious people, with an industrious, Christian
and God-fearing character.” Somehow the question of Kepler’s father’s piety and industry had been overlooked, and Kepler had been accepted. His instruction, room, and board were free, and he had a scholarship of six gulden annually for other expenses. Katharina’s father had placed at his grandson’s disposal the yield of one meadow “for better and more dignified
²
upbringing.” Thus Kepler was well
provided for as he moved into the Stift with other young men in their teens from all over Swabia who, like him, aspired to careers of service to the duke or the church. In his second year, on the recommendation of the magistrate of his native city, Weil der Stadt, Kepler received a further stipend of twenty gulden. There were few periods in his life when he was so free of financial worries as during
these university years.

Tübingen, like the University of Copenhagen, was steeped in the Philippist philosophy of university and seminary teaching. Though education at the Stift led to a specific goal and allowed students few choices about what they would learn, it was not a narrowly focused trade school. Theological studies didn’t even begin until the third year. Before that, in the Philippist
tradition of broad education, Kepler had to complete two years of ethics, dialectics, rhetoric,
Greek
, Hebrew, astronomy, and physics. An exam in the spring of the second year marked the end of these studies in the arts faculty. After that came two or three years of theological work. Kepler was closely supervised and received grades every quarter. The Stift regulated student behavior almost as
rigidly as the lower schools he had attended, and it expected its candidates in theology to avoid the disorderly student life enjoyed by others in the university.

Johannes Kepler was in his element amid all this knowledge to be had for the taking. Rarely has a young man been better equipped to make the most of an opportunity. Soon he had a reputation with teachers and students for being diligent,
sedate, and pious, and also for being good at casting horoscopes—a highly valued skill, as Tycho Brahe’s experience attested. According to Kepler’s own report, he managed to avoid conspicuous shortcomings except for a few outbursts of temper and a thoughtless prank or two, but he still had problems getting along with some of his fellow students. Particularly, he disliked one young man named
Kölin, who wanted to be his friend. “Although [Kölin] once made friends
³
with me he always argued with me,” wrote Kepler, and complained that an argument with Kölin was more like a “lovers’ spat,” though most of these arguments seem to have been about work. “With nobody else did I have a sharper and longer competition,” Kepler wrote.

Kepler’s work habits, though they were certainly productive,
were (and would continue to be all his life) a source of some disquiet for him. He was in a state of “permanent repentance about lost time
⁴
and permanent loss of time through my own fault.” He also admitted, “Although I am very industrious, I am the harshest hater of work. But I work for my thirst of knowledge. I am never lacking an object of my desire, my burning eagerness, to do research on
difficult matters.” His enthusiasms often went beyond his capacity to carry through on them. “In my eagerness, I talked myself into a lot of things that looked easy, but that were difficult and time-consuming in the carrying-out, because the mind is finer, faster, and quicker
than
the hand.” His mind continued to leap quickly from one matter to another, sometimes among apparently unrelated subjects.
“I talk well and I write well, as long as nothing is pushing me except what I have already thought of, but in reading and writing I continually start thinking about new things, words, figures of speech, arguments, new insights and understanding, what should be said and what should not be said.”

Among the activities that tempted him from his studies were the theatrical productions that the
Stift students presented at Shrovetide. The subject was always either biblical or classical, and since there were no women at the Stift, students like Johannes who were slight of stature and not too loutish or clumsy played the female roles. Johannes had the part of Mariamne in a tragedy about John the Baptist. Unfortunately the play was performed in the open marketplace, and Shrovetide was in midwinter.
That and the overexcitement caused him to contract a “feverish illness”—one of many bouts of bad health that threatened to hamper his studies.

Early in his university career, Kepler foresaw that theology and mathematics, including astronomy, were always going to be linked in his quest to discover for himself what was true and what was not. He was fortunate to have Michael Mästlin for his teacher
of mathematics and astronomy. Mästlin had won Tycho Brahe’s admiration in 1578, when Tycho was collecting publications about the comet of 1577 through friends abroad. Mästlin’s report stood out from the others. Compared with Tycho’s sophisticated methods, Mästlin’s were primitive: He had observed the comet by holding up a taut string to line up reference stars and then looked up those stars
in the Copernican Prutenic Tables to find their positions. The results were of great interest to Tycho, for both men had reached the same conclusion, with Mästlin’s observations being slightly more accurate. In a gracious letter written through a third party, Tycho suggested that they exchange observations and indicated that Tycho would be pleased to promote Mästlin’s career in any way possible.
At that juncture, Tycho was willing to share his work and findings with other astronomers and engage in an exchange of ideas.