Sky's Dark Labyrinth (14 page)

Karlova Street was one of the busiest thoroughfares in Prague. It was the last place in the Old Town that people passed through before crossing the Stone Bridge into the New Town, where lay the hope of imperial favour. And it was the first place to drown your sorrows on the trudge back home if things did not work out.

There were a number of inns squeezed into what used to be homes but had been hastily converted when the bridge opened. They attracted a steady stream of customers for as long as they were open. For those on tighter schedules or budgets, a pair of women in heavy shawls sold mulled wine from an urn over a fire in the street. For a few coppers they would ladle the aromatic drink into dented mugs. Just down from them, in his usual spot, a bearded knife-sharpener pedalled his whetstone.

All day, people trooped to and fro. Only in the evenings did the hubbub show any sign of abating, replaced by the occasional coach and the passage of evening revellers. Kepler hardly noticed these comings and goings any more; after a decade in the city his brain had long since learned to filter out the sounds.

Barbara sat facing the empty fireplace. She was wearing an old green dress that had once been saved for best. Now, spoiled by a few pulled threads, it served as everyday wear. Nothing had replaced it for best. Her arms were drawn tight, her face impassive. Most ominously of all, her mouth was drawn into a tight line.

Kepler had seen this mood brewing for days and had avoided it thus far, taking refuge in his study. Yet, the frustration of the silences at mealtimes and her turned back in bed at night were growing
impossible
to ignore.

‘You've not been yourself lately,' he stated matter-of-factly.

She ignored his comment.

‘Is it the children?'

In addition to Susanna, who was now eight, six years ago Barbara had given him Friedrich, and four years later Ludwig. The household rang with their chatter and Barbara was constantly busy.

‘Do they tire you out?' he asked. That at least brought a look of disdain. ‘Then what is it?'

‘Nothing.'

He edged into her line of sight. ‘Perhaps we should move. There are houses available in the New Town, close to the Palace. There's a better class of people over there.'

Barbara's head jerked around. ‘You don't understand, do you? We are objects of ridicule to the better class. “Mr and Mrs Stargazer”, that's all we are to them – ridiculous.'

‘It's not ridiculous to be known for what you do.'

‘We don't have the money to move house. What good is being Imperial Mathematician if you're not paid?'

The comment might just as well have been a knife between his ribs. He certainly felt the same physical pain. If only she would give him credit for the hours he spent standing in queues, shuttling from one office to another, begging for his ever-accumulating wages.

‘I sent a copy of the
Astronomia Nova
to England. I have no doubt that when the King reads it, he will look upon us with favour. We must just be patient, better times are ahead …'

‘James of England now! When has a single one of your schemes to win favour ever worked for us? Not so long back you convinced me we were moving to Tübingen because of this great new book of yours. Look what happened there.'

Kepler winced at the memory.

He had arrived unannounced at the university, having taken a detour on his way back from the Frankfurt Book Fair. The building was exactly as he remembered, all draughty halls and high windows. Waiting in the ornate entrance hall, he was unable to shake an
unsettling
feeling of coming home.

A group of young men in short black gowns passed by, displaying that universal student trait of one moment practising airs and graces, the next being consumed by horseplay. As Kepler watched, they jostled each other while approaching an archway, engineering it so one of their number would end up colliding with the stone pillar.

Kepler arranged his collar and straightened his jerkin, recalling the time he had sewn up the arms in Zimmerman's gown, forcing the wastrel to arrive at lectures apparently armless. It may not have been the most original prank in the world but it had been amusing at the time. Even when Zimmerman correctly guessed the culprit and Kepler was marched to the Chancellor's office, where he confessed and took his punishment, it had still been worth it.

His memories transformed into the sight of Mästlin rushing down the corridor, long gown billowing. It brought a smile to Kepler's face to see him again. Time, it seemed, had stood still for the Magister, and, for a moment, Kepler could believe that he was a student again, waiting for a tutorial.

‘Why are you here?' hissed the Magister, shattering the daydream.

‘Am I not welcome at my old university?'

Mästlin avoided eye contact. ‘Of course you are.'

‘I wanted to see you, Magister, talk to you. I miss our discussions.'

‘I'm a busy man, Johannes. You should have written ahead.'

‘Magister, you haven't replied to my letters for more than five years.'

The side of Mästlin's mouth twitched. ‘Johannes, your questions are beyond me. You have taken your mathematics to such a level that I cannot follow you any more.'

‘But you have read my letters?'

‘Yes, of course.'

‘And did you read my book on the new star? I sent you a copy.'

Mästlin glanced around the hallway. ‘You'd better come to my office.'

As Kepler followed, he noticed the scrutiny he was receiving from the fellow academics. He acknowledged one whom he recognised, but the old professor looked away.

‘Is everything alright here?' he asked Mästlin.

‘Yes, fine. Here we are.' Mästlin swept into an office, closed the door behind them and then looked perplexed about what to do next. He settled into his own chair, elbows resting on the desk.

‘The new star stayed firm in its position until it faded away. It was clearly in the realm of the fixed stars, and so clearly at odds with Aristotle's claim that the cosmos is unchanging. The old cosmology is wrong, possibly to its very core.'

‘Johannes, one small light in the sky cannot be used …'

‘Not
one
, it is clearly similar to the new star Tycho saw decades before. And there is more, Magister, much more. I have simplified Copernicus's concept of the Sun-centred universe to make it so obvious, it has to be true.'

‘Simplified it in what way?'

‘I have fought a war with Mars these past years, and now I have him bound in the chains of computation.'

‘Oh, do speak plainly. I remember this habit from your student days. It was annoying then.'

‘Very well,' Kepler said stiffly. ‘I have found the true shape of Mars's orbit. It is not a circle but an ellipse.' He might as well have said that God did not exist.

Mästlin looked at him with frank disbelief in his eyes.

‘I can thread every single one of Tycho's Mars observations. I have removed the need for every epicycle, every equant, every deferent. No more whirling cogs to set the mind reeling. All you need is the single ellipse for each planet. Simple.'

‘Where's the Sun in all this, in the middle of the ellipse?'

‘No, at one of the focal points. Let me demonstrate. Do you have a length of string?'

Mästlin performed a long-winded search in the drawers of his desk until he produced a length of rough twine. Kepler knotted it into a loop. ‘Now paper, pen and ink.'

Mästlin pushed a quill resting in an inkwell over to him, then retrieved a sheet of blank paper from a drawer.

‘And I need your fingers.'

Mästlin looked puzzled.

Kepler adjusted the loop of string and placed it on the paper. ‘In here, please.' He tapped his forefingers inside the loop, about three inches apart. Mästlin complied.

‘Now, don't move them.' Kepler inked the nib, pulled the string into a triangle with Mästlin's fingers as the base, and hooked the quill into the apex. He then drew a complete loop on the paper, allowing the shifting tension on the string to guide his pen around and back to where it started.

‘There,' he said.

Mästlin removed his fingers, and Kepler cleared away the string. On the paper was an ellipse. Kepler drew a dot where one of Mästlin's fingers had been and labelled it ‘sol'.

‘The distance between your fingers determines how extreme the elliptical shape becomes,' said Kepler. ‘Closer together makes the ellipse more circular, further apart makes it more elongated.'

‘If the Sun sits at one focus, what is at the other?'

‘Nothing.'

‘What guides the planets?'

‘A force emanating from the Sun that becomes weaker with distance. I know that because I have found another law of planetary motion.' Kepler picked up the pen again and drew two diverging lines from the Sun to the furthest end of the ellipse, forming a thin slice. ‘Say the area in this triangle is the same as the area in another one, like this.' He dipped the quill in the inkwell and drew two more lines, this time extending in the opposite direction from the dot to form a wider
triangular
segment from the Sun's position to the nearer end of the ellipse. He looked up to see if he were being clear.

‘Go on,' the older man urged.

‘The data shows that both of these areas are swept out in equal times, meaning that the further the planet is from the Sun, the more slowly it goes.'

‘Because it has a smaller distance to travel between the two lines,' said Mästlin, pointing to the base of the thinner triangle.

‘Precisely. Planets move faster when they are closer to the Sun because the force moving them is stronger.'

‘And all this is in your new book?'

‘All of it. I have called it
Astronomia Nova
because I believe it is just that: a new astronomy. I am now investigating the differences in the speeds of each planet at closest and furthest approach.'

Mästlin looked stunned. ‘Astonishing,' he murmured.

‘If I am to complete this work, I need security. My family grows apace, and Prague is growing restless …'

Mästlin snapped out of his daze, perhaps guessing where Kepler was heading. ‘I heard that Rudolph signed a peace treaty with his brother last year. They divided the Empire between them.'

‘They did, but it will not last. Rudolph has been trying to silence Matthias's claims to the throne for years. Last year, Matthias rebelled. He raised an army and marched on Prague but they were stopped outside the city by Rudolph's forces. They carved up the Empire and all seemed quiet for a while, but Rudolph was forced to rely on Protestant armies from the neighbouring estates to counter his brother. In return for their men, the estate owners secured religious freedoms for Lutherans that place the Emperor at odds with Rome. He's still smarting from that embarrassment because the estates fall within the Empire, so he should simply have commanded their loyalty, not had to bargain for it. There are now rumours that Rudolph wants revenge on the estates to restore his standing with Rome and look strong next to his brother. I believe the rumours are true. So, I am looking to move my family, and I would like to move this way.'

There, he had said it. He watched Mästlin carefully, hoping for some flicker in his eyes that might indicate a favourable reaction, but his former tutor was looking at the desktop.

‘There are those here who remember your theological debates. The way you disagreed with some key Lutheran principles.'

‘Magister, I have made no secret of the fact that I cannot believe in the transubstantiation. The metamorphosis of bread and wine into Christ's body and blood is too much like magic.'

‘Which is why we have the ubiquity doctrine: that God is
interwoven
into the fabric of all things and that is how we receive the blood and the body of Christ through the sacrament.'

‘You know that I cannot believe in that either. It is still too close to magic for my liking. The bread and the wine are symbolic. We receive Christ's special help at the time of communion through our prayers.' Kepler slumped back in his seat. Nothing had changed here in the fifteen years he had been away. They were still as intransigent as ever, still missing the whole point of Lutherism.

‘Europe is heading into darkness,' said Mästlin, standing up. ‘This is no time to hold an ambiguous position.'

‘My position has been clear since I was a student.' Kepler also rose to his feet.

‘Your position is ambiguous because you disagree with the ubiquity
doctrine – one of our foundation stones – and worse, you take your stance on it from the Calvinists.'

‘In this one thing alone, yes, I agree with the Calvinists – but on nothing else.'

‘I wish you well, Johannes, but I fear that there is no place for you here, not until we can count on your naked faith in Lutherism.'

‘But I need support if my ideas are to spread. I plan to send my book to academics and princes across Europe but I don't have many copies. I had to use much of the money Rudolph gave me to publish the book just to buy food. You could at least teach my theory of elliptical orbits or include it in the next edition of your
Epitome Astronomiae
. Let the truth be known.'

Suddenly Mästlin looked angry. ‘I will continue to teach Ptolemy's methods.'

‘I can scarcely believe my ears; it was you who taught me Copernicus in the first place.'

‘In private session, Johannes, not in public. Times have changed, hardened. Your name …'

‘But this one idea is a bigger monument to God than any cathedral.'

Mästlin jabbed a finger at Kepler. ‘You name is tainted. You are not trusted any more.'

An iciness lodged itself inside Kepler. He searched Mästlin's face for some hint of compassion. ‘I take it that's why you have not replied to my letters these past five years?'