John Banville - Kepler

Kepler turned again now to his work on Mars. Conditions around him had improved. Christian Longberg, tired of squabbling, had gone back to Denmark, and there was no more talk of their wager. Tycho Brahe too was seldom seen. There were rumours of plague and Turkish advances, and the stars needed a frequent looking to. The Emperor Rudolph, growing ever more nervous, had moved his imperial mathematician in from Benatek, but even the Curtius house was not close enough, and the Dane was at the palace constantly. The weather was fine, days the colour of Mosel wine, enormous glassy nights. Kepler sometimes sat with Barbara in the garden, or with Regina idly roamed the Hradcany, admiring the houses of the rich and watching the imperial cavalry on parade. But by August the talk of plague had closed the great houses for the season, and even the cavalry found an excuse to be elsewhere. The Emperor decamped to his country seat at Belvedere, taking Tycho Brahe with him. The sweet sadness of summer settled on the deserted hill, and Kepler thought of how as a child, at the end of one of his frequent bouts of illness, he would venture forth on tender limbs into a town made magical by the simple absence of his schoolfellows from its streets.

Mars suddenly yielded up a gift, when with startling ease he refuted Copernicus on oscillation, showing by means of Tycho's data that the planet's orbit intersects the sun at a fixed angle to the orbit of the earth. There were other, smaller victories. At every advance, however, he found himself confronted again by the puzzle of the apparent variation in orbital velocity. He turned to the past for guidance. Ptolemy had saved the principle of uniform speed by means of the punctutn equans, a point on the diameter of the orbit from which the velocity will appear invariable to an imaginary observer (whom it amused Kepler to imagine, a crusty old fellow, with his brass tri-quetrum and watering eye and smug, deluded certainty). Copernicus, shocked by Ptolemy's sleight of hand, had rejected the equant point as blasphemously inelegant, but yet had found nothing to put in its place except a clumsy combination of five uniform epicyclic motions superimposed one upon another. These were, all the same, clever and sophisticated manoeuvres, and saved the phenomena admirably. But had his great predecessors taken them, Kepler wondered, to represent the real state of things? The question troubled him. Was there an innate nobility, lacking in him, which set one above the merely empirical? Was his pursuit of the forms of physical reality irredeemably vulgar?

In a tavern on Kleinseit one Saturday night he met Jeppe and the Italian. They had fallen in with a couple of kitchen-hands from the palace, a giant Serb with one eye and a low ferrety fellow from Württemberg, who claimed to have soldiered with Kepler's brother in the Hungarian campaigns. His name was Krump. The Serb rooted in his codpiece and brought out a florin to buy a round of schnapps. Someone struck up on a fiddle, and a trio of whores sang a bawdy song and danced. Krump squinted at them and spat. "Riddled with it, them are," he said, "I know them. " But the Serb was charmed, ogling the capering drabs out of his one oystrous eye and banging his fist on the table in time to thejig. Kepler ordered up another round. "Ah," said Jeppe. "Sir Mathematicus is flush tonight; has my master forgot himself and paid your wages?" "Something of that, " Kepler answered, and thought himself a gay dog. They played a hand of cards, and there was more drink. The Italian was dressed in a suit of black velvet, with a slouch hat. Kepler spotted him palming a knave. He won the hand and grinned at Kepler, and then, calling for another jig, got up and with a low bow invited the whores to dance. The candles on the tavern counter shook to the thumping of their feet. "A merry fellow, " said Jeppe, and Kepler nodded, grinning blearily. The dance became a general rout, and somehow they were suddenly outside in the lane. One of the whores fell down and lay there laughing, kicking her stout legs in the air. Kepler propped himself against the wall and watched the goatish dancers circling in a puddle of light from the tavern window, and all at once out of nowhere, out of every where, out of the fiddle music and the flickering light and the pounding of heels, the circling dance and the Italian's drunken eye, there came to him the ragged fragment of a thought. False. What false? That principle. One of the whores was pawing him. Yes, he had it. The principle of uniform velocity is false. He found it very funny, and smiling turned aside and vomited absent-mindedly into a drain. Krump laid a hand on his shoulder. "Listen, friend, if you puke up a little ring don't spit it out, it'll be your arsehole. " Somewhere behind him the Italian laughed. False, by Jesus, yes!

They went on to another tavern, and another. The Serb got lost along the way, and then Felix and the dwarf reeled off arm in arm with the bawds into the darkness, and Krump and the astronomer were left to stagger home up the Hradcany, falling and shouting and singing tearful songs of Württemberg their native land. In the small hours, his elusive quarters located at last, Kepler, a smouldering red eye in his mind fixed on the image of a romping whore, attempted with much shushing and chuckling to negotiate Barbara's rigid form into an exotic posture, for what precise purpose he had forgotten when he woke into a parched and anguished morning, though something of the abandoned experiment was still there in the line of her large hip and the spicy tang of her water in the earthen pot under the bed. She would not speak to him for a week.

Later that day, when the fumes of the charnel house had dispersed in his head, he brought out and contemplated, like a penniless collector with a purloined treasure, the understanding that had been given to him that the principle of uniform orbital velocity was a false dogma. It was the only, the obvious answer to the problem of Mars, of all the planets probably, and yet for two thousand years and more it had resisted the greatest of astronomy's inquisitors. And why had this annunciation been made to him, what heaven-hurled angel had whispered in his ear? He marvelled at the process, how a part of his mind had worked away in secret and in silence while the rest of him swilled and capered and lusted after poxed whores. He experienced an unwonted humility. He must be better now, behave himself, talk to Barbara and listen to her complaints, be patient with the Dane, and say his prayers, at least until the advent of new problems.

They were not long in coming. His rejection of uniform velocity threw everything into disarray, and he had to begin all over again. He was not discouraged. Here was real work, after all, fully worthy of him. Where before, in the Mysterium, there had been abstract speculation, was now reality itself. These were precise observations of a visible planet, coordinates fixed in time and space. They were events. It was not by chance he had been assigned the study of Mars. Christian Longberg, that jealous fool, had insisted on keeping the lunar orbit; Kepler laughed, glimpsing there too the quivering tips of angelic wings, the uplifted finger. For he knew now that Mars was the key to the secret of the workings of the world. He felt himself suspended in tensed bright air, a celestial swimmer. And seven months were becoming seventeen.

Tycho told him he was mad: uniform velocity was a principle beyond question. Next he would be claiming that the planets do not move in perfect circles! Kepler shrugged. It was the Dane's own observations that had shown the principle to be false. No no no, and Tycho shook his great bald head, there must be some other explanation. But Kepler was puzzled. Why should he seek another answer, when he had the correct one? There stood at the hatch of his mind an invoice clerk with a pencil and slate and a bad liver, who would allow no second thoughts. Tycho Brahe turned away; what little chance there had been that this Swabian lunatic would solve Mars for him was gone now. Kepler plucked at him, wait, look-where is my compass, I have lost my compass-the thing was as good as done! Even assuming a variable rate of speed, to define the orbit he had only to determine the radius of its circle, the direction relative to the fixed stars of the axis connecting aphelion and perihelion, and the position on that axis of the sun, the orbital centre, and the punctum equans, which for the moment he would retain, as a calculating device. Of course all this could only be done by a process of trial and error, but… but wait! And Tycho swept away, muttering.