Galileo's Dream

Chapter two I Primi Al Mondo

The next night, back in Padua, Galileo went out into his garden and aimed his best occhialino at the moon. He left Mazzoleni sleeping by the kitchen fire, woke none of the servants; the house was asleep. This was the hour, as on so many nights, when his insomnia took hold of him.

Now his mind was filled with the stranger’s blade of a face, his intense gaze. Have you looked at the moon? The moon tonight was near its first quarter—the bright part almost exactly half the whole, the dark part easily visible against the night sky. An obvious sphere. Galileo sat on a low stool, held his breath, then brought his right eye to the eyepiece. The little black circle of glass was marked on its left side by a luminous white patch. He focused on it.

At first he saw nothing but a chiaroscuro flecking of grayish black and brilliant white, the tremble of the white seeming to flow over the dark spots. Ah; hills. A landscape. A world seen from above.

A view from world to world.

He loosened the screw on the tripod head and tapped the tube, trying to capture in the glass the tip of the moon’s upper crescent. He tightened the screw, looked again. Brilliant white horn; and a dark gray in the curve of the horn, a blackness just slightly washed with white. Again he saw an arc of hills. There, at the border of light and dark, was a flat dark patch, like a lake in shadow. The sunlight was obviously shining horizontally over the landscape—as it would be, of course, as he was looking at the area experiencing dawn. He was looking at a sunrise on the moon, twenty-eight times slower than a sunrise on Earth.

There was a little round valley; there another one. Any number of circles and arcs, in fact, as if God had been fooling around up there with a compass. But the strongest impression remained the range of hills, there on the border of black and white.

The moon was a world, like the Earth was a world. Well, of course. He had always known this.

As for the assertions the Aristotelians made about the moon, that because it was in the heavens it was therefore a perfect sphere, made of some unearthly crystal that was of unchanging purity—well, its ordinary appearance had always rendered that a very suspicious statement. Now it was clearer than ever that Aristotle had been wrong. This was no great surprise—when indeed had he been right in the natural sciences? He should have stuck to his strength, which was rhetoric. He had had no mathematics.

Galileo got up and went into the workshop to get his current folio, and a quill and inkpot. He wondered if he should wake Mazzoleni, then decided against it. There would be other nights. He could feel his blood pounding in his head; his neck muscles were sore. This was his night. No one had ever seen these things. Well, perhaps the stranger had, but Galileo suppressed that thought in order to glory in his own moment. All the years, all the centuries had come and gone, the stars rotating above them night after night, and only now had someone seen the hills of the moon.

The moon must rotate on its axis at the same speed it circled the Earth, to keep the same side always facing it; this was odd, but no odder than many other phenomena, such as the fact that the moon and the sun were the same size in the sky. These things were either caused, or accidental; it was hard to tell. But it was a rotating sphere, that was clear. And so was the Earth also a rotating sphere? Galileo wondered if Copernicus’s advocacy of this old Pythagorean notion could be correct.

He looked through the glass again, relocated the white hills. The dark part west of them was extremely interesting. Land in shadow, obviously. Perhaps there were lakes and seas too, though he could see no sign one way or the other. But it was not as black as a cave or a dark room at night. One could make out dim large features, because the area was very slightly illuminated. That could not be direct sunlight, obviously. But just as the moonlight illuminating his garden at this moment was really sunlight bouncing off the moon to him, he was no doubt also seeing the dark part of the moon illuminated by sunlight that had bounced off the Earth and struck it—and then bounced back yet again, of course, to get to his eyes. From sun to Earth to moon and then back to him—which would explain the successive diminutions in brightness. As sunlight was to moonlight, moonlight was to the dark side of the moon.

The next morning he said to Mazzoleni, “I want a stronger magnification, something like twenty or thirty times.”

“Whatever you say, maestro.”

They manufactured a lot of spyglasses. Making the objective lenses bigger and smoother, while keeping the eyepiece lenses at their original size and grinding them both deeper and smoother, led to very satisfactory jumps in magnifying power. In a matter of weeks they had glasses that showed things twenty—twenty-five—thirty—finally thirty-two times closer than the unaided eye could see them. There they hit their limit; the lenses could not be made bigger or smoother, and the tubes were twice as long as when they had begun. Also, as magnifying power grew, what one actually saw through the glass contracted down to a very small field of view. One could move one’s eye around the eyepiece a bit to broaden the view, but not by very much. Accurate aiming was important, and Galileo got better at this by attaching an empty spotting tube to the side of the strongest glass. They also had to deal with a white glare that invaded the sides of the larger images, where the irregularities in the lenses also tended to cluster, so that the outer circumference of the image was often nearly useless.

Here, Galileo put to use a solution he had discovered to deal with the rainbow rings that plagued his own eyes’ vision, especially of things seen at night. This unhappy phenomenon he tended to attribute to the strange incident of his near-death experience in the cellar of the Villa Costozza, which he also believed had caused his rheumatism, bad digestion, headaches, seizures, melancholia, hypochon dria, and so on. Vision problems were only one more remnant of that ancient disaster, and he had long since discovered that if he looked at something through his fist, the aurora of colored light surrounding the thing would be blocked from view. Now he tried the same remedy with the new spyglasses, fashioning with Mazzoleni’s help a cardboard sleeve that could be fitted over the objective. The most effective one left an oval opening over the lens that blocked most of the outer third of its area. Why an oval worked better than a circle he had no idea, but it did. The glare was eliminated, and the image that remained was about as large as before, and very much sharper.

As the spyglasses got stronger, things in the sky were becoming visible that had not been visible before. One night, after a long inspection of the moon, he swung the glass across the sky toward the Pleiades, just risen above the house roof. He looked into the glass.

“My God,” he said, and felt his body ringing. Around the Seven Sisters were scores of stars. The familiar seven stars of the gorgeous little constellation were brighter than the rest, but surrounding them were thickets of lesser stars, granulated almost to white dust in places. The sense of enormous depth in the little black circle was palpable, almost vertiginous; he swayed a little on his stool, mouth hanging open. He sketched a quick map of the newly crowded group, making the familiar sisters little six-pointed stars like a child would draw, with the new stars tiny crosses—the drawing done almost unconsciously, a kind of nervous habit, deeply engrained after so many years of exercising it. Until he sketched something down, his hand would itch with the urge.

He looked until his eyes hurt, and the points of light swam in the eyepiece like gnats in the sun. He was cold, almost shivering, his bad back like a rusty hinge inside him. He felt that he would sleep the moment he lay down: a luscious feeling for a lifelong insomniac. He bathed in it as he stumbled off to bed.

His empty bed. No Marina. He had kicked her out, and life was ever so much more peaceful. Nevertheless, he felt a quick stab of regret as he dove into the deep pool of sleep. It would have been nice to have someone to tell. Well, he would tell the world.

The thought almost woke him.

Only six days after his demonstration to the Venetian senate, his reward came, in the form of a new contract offer. Procurator Antonio Prioli, one of the heads of the university in Padua, came out of the Sala del Senato to take Galileo by the hand. “The senate, knowing the way you have served Venice for seventeen years, and sensible of your courtesy in offering your occhialino as a present to the Republic, has ordered your election to the professorship for life, if you are willing, with a salary of a thousand florins a year. They are aware that there remains a year on your current contract, and yet want the increase in salary to begin this very day.”

“Please convey to His Serenity and all the pregadi my deepest thanks for this most kind and generous offer, Your Honor,” Galileo said. “I kiss their hands, and accept with the utmost gratitude.”

“Shit,” he said the moment he was out of earshot. And back at home he started cursing in a way that emptied the rooms well before he stormed through them, kicking the furniture. “Shit shit shit. Those pricks! Those cheap bastards, those soddomitecci!”

He remembered as he always did that Cremonini, an old duffer Galileo had enjoyed sparring with through the years, already made a thousand florins a year from the Venetian senate. That was the difference between the standing of philosophy and mathematics in this world—an inverse ratio to justice, as so often happened. The worst philosopher was paid twice the best mathematician.

Then also, a salary fixed in perpetuity meant there would never be another raise, and Galileo already knew to the last quattrini his expenses, which were such that this raise would only just cover them, leaving him still unable to pay off his sister’s dowry and his other outstanding debts.

Also, the salary was a salary, paid for his teaching, as before—meaning there would be no time to write up his experiments, or make new ones. All that work in the notebooks in the workshop would continue to lie there moldering.

So this was not exactly the most exciting result one could have imagined, given the extraordinary power of his new device, and its strategic importance—obvious to everyone who had witnessed the demonstration. The triumph of that day had had Galileo imagining a lifetime sinecure, all his debts and expenses paid, and afterward free from all work except research and consultation, which he would have applied most faithfully to the good fortune of La Serenissima. They would have benefited greatly, and in any duchy or principality or kingdom this kind of patronage would not have been unusual. But Venice was a republic, and courtly patronage as it was practiced in Florence or Rome, or almost anywhere else in Europe, did not exist here. Gentlemen of the republic worked for the republic, and were paid accordingly. It was an admirable thing—if you could afford it.

“Shit,” he repeated weakly, staring at his workshop table. “Those cheap bastards.” But a part of his mind was already calculating what the thousand florins a year would do to meet expenses and knock off debts.

Then he heard in a letter from Sarpi that some of the senators had complained to the body at large that the spyglass was a commonplace in Holland and elsewhere in northern Europe, so that it had not really been Galileo’s achievement, and he had presented his device under false pretenses.

“I never said I invented the idea,” Galileo protested. “I only said I made it much better, which I did! Tell those cheap bastards to find a spyglass as good as mine somewhere else, if they think they can!” He ripped off a long letter that he sent to Sarpi to give to the senators:

News arrived at Venice, where I happened to be at the moment, that a Dutchman had a glass looking through which one could see distant things as clearly as if they were near. With this simple fact I returned to Padua, and pondering on the problem, I found the solution on the first night home, and the next day I made an instrument and reported the fact to my friends at Venice. I made a more perfect instrument, with which I returned to Venice, and showed it to the wonder and astonishment of the illustrati of the republic—a task which caused me no small fatigue.

But perhaps it may be said that no great credit is due for the making of an instrument, when one is told beforehand that the instrument exists. To this I reply, the help which the information gave me consisted of exciting my thoughts in that particular direction, and without that, of course it is possible they may never have gone that way. But that the simple information itself made the act of invention easier to me I deny, and say more—to find the solution to a definite problem requires a greater effort of genius than to resolve one not specified. For in the latter case accident, mere chance, may play the greater part, while in the former all follows from the work of the reasoning and intelligent mind. Thus, we are quite sure that the Dutchman was a simple spectacle-maker, who, handling by chance different forms of glasses, looked also by chance through two of them, and saw and noted the surprising result, and thus found the instrument. Whereas I, at the mere news of the effect obtained, discovered the same instrument, not by chance, but by way of pure reasoning! I was not assisted in any way by the knowledge that the conclusion at which I aimed already existed.

Some people may believe that the certainty of the result aimed at affords great help in attaining it: let them read history, and they will find that Archites made a dove that could fly, and that Archimedes made a mirror that burned objects at great distances. Now, by reasoning on these things, such people will doubtless be able, with very little trouble and with great honor and advantage, to tell us how they were constructed. No? If they do not succeed, they will then be able to testify to their own satisfaction that the ease of fabrication which they had promised themselves from the foreknowledge of the result is very much less than what they had imagined—

“Idiots that they are!” Galileo shouted but did not add to the end of the letter, signing it conventionally and sending it off.

Naturally Sarpi did not forward this letter to the senate, but rather came out to Padua to assuage his angry friend. “I know,” he said apologetically, putting his hand to Galileo’s freckled cheek, now as red as his hair as he recounted the reasons for his fury. “It isn’t fair.”

And it was even less fair than Galileo thought, for Sarpi now told him that the senate had decided that the stipulated raise in Galileo’s salary was not to go into effect immediately after all, but would begin the following January.

At this Galileo blew up again. And after Sarpi left, he immediately took action to deal with the insults, working in two directions. In Venice, he returned to the city with a much more powerful spyglass, the best his artisans had made so far, and gave it to the doge as a present, indicating again how useful it would be to the protection of the republic, how grateful he was for the new contract, how much the splendiferousness of the doge illuminated not just the Serenissima but the entire watershed of the Po, et cetera. Dona would take note of this generosity, perhaps, in the face of what could be seen as a very tepid response from his senate. And then maybe he would act to revise the raise accordingly. It was not the likeliest response, but it could happen.

Then, on the Florentine front—always a part of his life, even in these last seventeen years in Padua working for Venice—Galileo wrote to young Grand Duke Cosimo’s secretary Belisario Vinta, telling him about the spyglass, offering to give the prince one of them and to instruct him in its use. A few of the closing phrases of this letter began the process of asking for patronage at the Medici court.

There were some difficulties to be negotiated here. Galileo had been tutor to young Cosimo when his father Ferdinando was the grand duke, and that was good. But he had also been asked to work up a horoscope for Ferdinando the previous year, and had done so, and found that the stars predicted a long and healthy life for the grand duke, in the usual way. But then, shortly thereafter, Ferdinando had died. That was bad. In the tumult of the funeral and the succession no one had said anything, nor even seemed to remember the horoscope, except for a single penetrating glance from Vinta the next time they met. So perhaps in the end it had not mattered. And Galileo had taught Cosimo his mathematics, and treated him very kindly, of course, so that they had grown fond of each other. Cosimo was a bright young man, and Cosimo’s mother, the Grand Duchess Christina, was a very intelligent woman, and fond of Galileo—indeed, his true first patron at that court. And as Cosimo was so young, and new to his rule, she was a regentlike power. So the possibilities there were very real. And when all was said and done, Galileo was a Florentine; it was his home. His family was still there, which was bad, but unavoidable.

So, still very angry at the Venetians for their ingratitude, he neglected his classes at Padua, wrote great flurries of letters to influential friends, and began to lay plans to move.

During this time, despite the discord and chaos of the tumble of days, he spent every cloudless night out in the garden, looking through the best glass they had on hand. One night he woke Mazzoleni and took him out to look at the moon. The old man peered up through the tube and then pulled his head back, grinning, shaking his head in amazement. “What does it mean?”

“It’s a world, like this one.”

“Are there people there?”

“How should I know?”

When the moon was up, and not too full, Galileo looked at it. Long ago he had taken drawing lessons from his Florentine friend Ostilio Ricci, the better to be able to sketch his mechanical ideas. One of the exercises in Ricci’s treatise on perspectival drawing had been to draw spheres studded with geometrical figures, like raised pyramids or cubes, each one of which had to be drawn slightly differently to indicate where they stood on the hidden surface of the sphere beneath them. This was a meticulous and painstaking form of practice, very polito, at which Ricci had conceded Galileo eventually became the superior. Now Galileo found that it had given him the necessary skills, not just to draw the things the glass showed on the moon, but even to see them in the first place.

It was particularly revealing to draw the moon’s terminator, where light and shadow mixed in patterns that changed from night to night. As he wrote in his workbook: With the moon in various aspects to the sun, some peaks within the dark part of the moon appear drenched in light, although very far from the boundary line of the light and darkness. Comparing their distance from that boundary line to the entire lunar diameter, I found that this interval sometimes exceeds the twentieth part of the diameter.

The moon’s diameter had been proposed since antiquity to be about two thousand miles; thus he had enough to complete a simple geometrical calculation of the height of these lunar mountains. He drew the moon as a circle, then on it drew a triangle with one side the radius at the terminator, another a radius running up to the tip of the lit mountain in the dark zone, and the third line following the beam of sunlight from the terminator to the mountaintop. The two sides meeting at the terminator would be at right angles, and he had distances for both, based on the assumed diameter, and thus he could use the Pythagorean theorem to calculate the length of the hypotenuse. Subtracting the moon’s radius from that hypotenuse, one was left with about four miles of difference—which was the height of the mountain above the surface at the terminator.

But on Earth, he wrote, no mountains exist that reach even to a perpendicular height of one mile. The mountains on the moon were taller than the Alps!

One night when the moon was in its last quarter, he spotted a perfectly round crater, right in the middle of the terminator, and very near the equator. He drew it a bit bigger than he saw it, to emphasize how prominent it was to the eye, and how clearly it stood out from its surroundings. A good astronomical drawing, he decided, had to evoke the sight that subsequent viewers would look for, rather than represent it to perfect scale, which in the diminution of the drawing simply made it too small. Paying attention was itself a kind of magnification.

Drawing the constellations with their new host of companion stars was a different kind of problem, easier in some ways, as being mostly a schematic, but much harder too, in that there was no chance of representing what the view through the glass actually looked like. He altered sizes far beyond what he saw, to give an impression of the different brightnesses, but using black on white to represent white on black would never be satisfactory. White marks on black, as in an etching, would be better.

He drew till his fingers got too cold. He made fair copies in the mornings, exaggerating to make the impressions bolder than ever. He made ink washes, very delicate; also bold schematics that would serve as guides to an engraver, because already he had plans for a book to accompany the spyglasses, just as an instruction manual had accompanied his military compass. Although here it really came down to seeing for one’s self. The Milky Way, for instance; he could see that it was composed of a vast number of stars granulated together. A truly astonishing finding, but there was no way at all to draw it. People would have to see for themselves.

As November wore on, and the nights got colder, he fell deeply into his new routine. He had always been an insomniac, and now there was a useful way to spend those sleepless hours. He simply did not go to bed, but stayed out on the terrace by the occhialino, looking through it and jotting down notes, comfortable in the solitary silence of the sleeping town. He had not known how much he enjoyed being alone. He wrote up what he had observed at dawn, and then slept through many a bright cool morning, wrapped in a blanket against a sunny wall in the corner, under the gnomon of the house’s big L.

With the shorter days of December came winter, and clouds. On those nights he read, or caught up on his sleep, if he could. But on many a night he woke every hour or two, his brain full of stars, and went out to check the sky. If it had cleared, he would stir the coals of the kitchen fire and put a pot of mulled wine on the grate, add a few sticks and go out to set up the glass, feeling that swirl of dust in the blood that he loved so much. He was on the hunt all right, and never had he had such a quarry! Nothing could keep him from looking when the night was clear. If his day work had to suffer—and it did—so be it. Those bastard pregadi didn’t deserve his work anyway.

He had ordered one of the worktables moved onto the terrace next to the garden, and placed under a table umbrella next to a couch. He had a lantern that could be shuttered, and workbooks, inkpots, and quills; and three spyglasses on tripods, each with different strengths and occlusions. Lastly, blankets to throw over his shoulders. Mazzoleni and the cook kept things running in the mornings while he slept, and stocked the supplies for his nighttime needs; both were the kind of person who falls asleep at sunset, so they didn’t see him at work unless he forced them to. After a while, he never did. He liked being by himself through the frosty nights, looking at first one thing and then another.

On the night of January 7, 1610, he was out looking at the planets. As he had written in a letter he was composing for young Antonio Medici: The planets are seen very rotund, like little full moons, and of a roundness bounded and without rays. But the fixed stars do not appear so; rather they are seen fulgurous and trembling, much more with the glass than without, and so irradiated that what shape they possess is not revealed.

So the planets, being obvious little disks, were interesting. And Jupiter was now in the west after sunset. It was the biggest of the planets in the glass—no surprise to anyone used to the way it dominated the night sky whenever it was visible.

Galileo got it in the middle of the eyepiece, and then saw that there were three bright stars to left and right of it, aligned with it in the plane of the ecliptic. He marked their position on a new sheet of his letter to Antonio, and looked at them for a long time. They did not twinkle like the stars, but gleamed steadily. They were almost perfectly on a line with each other. They were almost as bright as Jupiter, or even brighter, although smaller. Jupiter itself was a very distinct disk.

The next night he looked at Jupiter again, and was shocked to find that the three stars were still there, but this time all to the west of the great planet, whereas on the previous night two of them had been to its east. He wondered if the ephemerides for the night was wrong.

On January 9 it was cloudy, and nothing could be seen. But the night of January 10 was clear again.

This time only two of the bright stars were there, both to the east of Jupiter. One was slightly less bright than the other, though on the previous nights they had all been the same.

Mystified—intrigued to the point of obsession—Galileo started a new sheet in his workbook, and copied there the diagrams he had already written in at the end of the letter to Antonio. The letter itself he put aside, as being premature.

In his new desire for night, the days themselves passed slowly, and he did the necessary work without paying the slightest attention to it, as if dreaming on his feet. This was a sign, well-recognized by the household: he was on the hunt. And just as they never woke sleepwalkers for fear of damaging their sanity, they left him alone at these times, and kept the boys quiet and the students at bay, and put food in him almost as if spoon-feeding a baby. Of course, it was true he would beat them if they distracted him, but they enjoyed the craft of it too.

On the night of January 12, Galileo trained the glass on Jupiter in the last moments of twilight. At first he could see again only two of the little bright stars, but an hour later, when it was fully dark, he checked again, and one more had become visible, very close to Jupiter’s eastern side.

He drew arrows trying to clarify to himself how they were moving, shifting his attention between the view through the glass and his sketches on the page. Suddenly it became clear, there in the reiterated sketches: the four stars were moving around Jupiter, orbiting it in the same way the moon orbited the Earth. He was seeing circular orbits edge-on; they lay nearly in a single plane, which was also very close to the plane of the ecliptic, in which the planets themselves moved.

He straightened up, blinking away the tears in his eyes that always came from looking too long, and that this time came also from the sudden surge of an emotion he couldn’t give a name to, a kind of joy that was also shot with fear. “Ah,” he said. A touch of the sacred, right on the back of his neck: God had tapped him. He was ringing.

No one had ever seen this before. People had seen the moon, had seen the stars; they had never seen this. I primi al mondo! The first man to see Jupiter’s four moons, which had been circling it since the creation.

Everything he had seen over the last week fell into place. He stood, staggering a little under the impact of the idea, and circled the work-table as if imitating a moon. When there had been only two dots, the others could have been behind the big planet—or before it. And he saw also that the orbiting moon now outermost could perhaps have moved so far away from Jupiter as to be outside his eyepiece’s little circle. The shifts in position suggested they were moving fairly quickly. Earth’s moon took only twenty-eight and a half days for its orbit. These four seemed faster, and perhaps could be moving at differing speeds, just as the planets moved at differing speeds in the sky.

If he were right, then he could expect to see several more things. Seeing the orbits side-on, the moons would appear to slow down as they approached their maximum distance from Jupiter, and be fastest when right next to it. They would also disappear when behind it (or before it) in a regular pattern, and always reappear on the other side, never on the same side. Repeated observations should make it possible to sort out which moon was which, and determine which orbited closest to Jupiter and which farthest away. Knowing that would help him to calculate each orbital period, and that would allow him to keep steady track of them, and even predict where they would be, in a Jovian ephemerides of his own device.

“My God,” he said, overwhelmed at these thoughts, suddenly weeping, feeling he should fall to his knees to say a prayer in thanks to God—only his knees were too stiff; he was too cold. Anyway, it was looking through the glass that was the prayer. “I’m the first in the world!”

Which—when he recovered from the awe of it—really should be something he could turn to advantage. A truly new thing in the world—how could it not be useful? He had to hop about in the frigid night air to express his happiness. Mazzoleni and the rest would have laughed to see it, as they had laughed all the times they had seen it, after one good discovery or another. But none so good as this! He chortled; he shuffled around the terrace in a dance with the spyglass as his partner. He felt an urge to ring the workshop bell; he even began to walk toward the workshop, to wake Mazzoleni and the rest, to share the news with somebody. But he was the bell he wanted to ring, and if he woke the others, Mazzoleni would just nod and grin his gaptoothed grin, and be pleased that the new instrument was working better than the previous one. What went on in the sky did not matter to him.

So Galileo stopped in his tracks and returned to the terrace. He recommenced his little contradance around the tripod and worktable, singing nonsense words to himself under his breath. Tomorrow he would write up his news, and publish it as soon as possible after that, to share it with the world. Everyone would know, everyone would look and see. But only he would be first—first always, first forever. Feeling warm in his cloak, he settled on the stool under the tripod to look some more.

Then there came a knock at the garden gate. And he knew who it was.