Tycho and Kepler

Tycho and Kepler

Tycho Brahe

A provincial schoolteacher of humble origins, unknown to all but a few mathematicians, Johannes Kepler was diffident about Tycho’s offer to join him in Prague. But the decision was made for him. In 1598, one of the many premonitory tremors of the coming Thirty Years’ Was engulfed him. The local Catholic archduke, steadfast in dogmatic certainty, vowed he would rather “make a desert of the country than rule other heretics” (By no means the most extreme such remark in medieval or Reformation Europe. Upon being asked how to distinguish the faithful from the infidel in the siege of a largely Albigensian city, Domingo de Guzman, later known as Saint Dominic, allegedly replied: “Kill the all. God will know his own”.) Protestants were excluded from economic and political power. Kepler’s school was closed, and prayers, books and hymns deemed heretical were forbidden. Finally the townspeople were summoned to individual examinations on the soundness of their private religious convictions, those refusing to profess the Roman Catholic faith being fined a tenth of their income and, upon pain of death, exiled forever from Graz. Kepler chose exile: “Hypocrisy I have never learned. I am in earnest about faith. I do not play with it”.

Dynascope RV-6. “Hypocrisy I have never learned. I am in earnest about faith. I do not play with it” (Johannes Kepler). Image: In public domain.

Leaving Graz, Kepler, his wife and stepdaughter set out on the difficult journey to Prague. Theirs was not a happy marriage. Chronically ill, having recently lost two young children, his wife was described as “stupid, sulking, lonely, melancholy”. She had no understanding of her husband’s work and, having been raised among the minor rural gentry, she despised his impecunious profession. He for his part alternately admonished and ignored her, “for my studies sometimes made me thoughtless; but I learned my lesson, I learned to have patience with her. When I saw that she took my words to heart, I would rather have bitten by own finger to give her further offense”. But Kepler remained preoccupied with his work.

He aspired to become a colleague of the great Tycho Brahe, who for thirty-five years had devoted himself, before the invention of the telescope, to the measurement of a clockwork universe, ordered and precise. Kepler’s expectations were to be unfulfilled. Tycho himself was a flamboyant figure, festooned with a golden nose, the original having been lost in a student duel fought over who was the superior mathematician. Around him was a raucous entourage of assistants, sycophants, distant relatives and assorted hangers-on. Their endless revelry, their innuendoes and intrigues, their cruel mockery of the pious and scholarly country bumpkin depressed and saddened Kepler : “Tycho… is superlatively rich but knows not how to make use of it. Any single instrument of his costs more than my and my whole family’s fortunes put together”.

Johannes Kepler

Impatient to see Tycho Brahe’s astronomical data, Johannes Kepler would be thrown only a few scraps at a time: “Tycho gave me no opportunity to share in his experiences. He would only, in the course of a meal and, in between other matters, mention, as if in passing, today the figure of the apogee of one planet, tomorrow the nodes of another… Tycho possesses the best observations… He also has collaborators. He lacks only the architect who would put it all this to use. » Tycho was the greatest observational genius of the age, and Kepler the greatest theoretician.

Each knew that, alone, he would be unable to achieve the synthesis of an accurate and coherent world system, which they both felt to be imminent. But Tycho was not about to make a gift of his life’s work to a much younger potential rival. Joint authorship of the results, if any, of the collaboration was for some reason unacceptable.

The birth of modern science – the offspring of theory and observation – teetered on the precipice of their mutual mistrust. In the remaining eighteen months that Tycho was to live, the two quarreled and were reconciled repeatedly.

Let me not seem to have lived in vain. Image: A Flashing Texture by © Megan Jorgensen (Elena)

At a dinner given by the Baron of Rosenberg, Tycho, having robustly drunk much wine, “placed civility ahead of health”, and resisted his body’s urging to leave, even if briefly, before the baron. The consequently urinary infection worsened when Tycho resolutely rejected advice to temper his eating and drinking. On his deathbed, Tycho Brahe bequeathed his observations to Kepler, and “on the last night of his gentle delirium, he repeated over and over again these words, like someone composing a poem: “Let me not seem to have lived in vain… Let me not seem to have lived in vain…”

After Tycho Brahe’s death, Johannes Kepler, now the new Imperial mathematician, managed to extract the observations from Tycho’s recalcitrant family. His conjecture that the orbits of the planets are circumscribed by the five platonic solids were no more supported by Tycho’s data than by Copernicus’.

Tycho’s observation of the apparent motion of Mars and other planets through the constellations were made over a period of many years. These data, from the last few decades before the telescope was invented, were the most accurate that yet had been obtained. Kepler worked with passionate intensity to understand them. What real motion of the Earth and Mars about the Sun could explain, to the precision of measurement, the apparent motion of Mars in the sky, including its retrograde loops through the background constellations.