The Clockwork Universe: Isaac Newton, the Royal Society, and the Birth of the Modern World - Edward Dolnick (2011)
Part II. Hope and Monsters
Chapter 17. Never Seen Until This Moment
Virginia Woolf famously remarked that “on or about December 1910 human character changed.” She might have picked a different date, almost precisely three centuries earlier. On January 7, 1610, Galileo turned a telescope to the night sky. Human nature—or at least humankind’s picture of the universe and our own place within it—changed forever.
Three months later Galileo told the world what he had seen, in a book called The Starry Messenger. On the day the book reached Venice, the English ambassador, Sir Henry Wotton, sent a startled letter home. “I send herewith unto his Majesty the strangest piece of news (as I may justly call it) that he hath ever yet received from any part of the world.” Sir Henry’s emphasis on the word news was fitting. What he was about to pass on was not merely “news” in the modern, journalistic sense but “news” in the truest sense—a report of something that until that moment had never been seen or even imagined.
What was this astonishing news? “The Mathematical Professor at Padua . . . hath discovered four new planets rolling about the sphere of Jupiter”—four new planets in the unchanging heavens—and that was only part of the story. Galileo had also uncovered the secret of the Milky Way; he had learned, for the first time, the true nature of the moon, with all its pockmarked imperfections; he had found that the supposedly pristine sun was marred with black spots. In short, Wotton reported in slack-jawed astonishment, “he hath . . . overthrown all former astronomy.”
Four decades before, the Danish astronomer Tycho Brahe had startled the world with a discovery of his own. In 1572 Tycho saw what he took to be a new star in the constellation Cassiopeia.23 The last of the great naked-eye astronomers, Tycho was a meticulous observer with an unsurpassed knowledge of the sky. He had known “all the stars in the sky” from boyhood, he boasted, but even casual stargazers knew Cassiopeia, with its striking W shape. The supposed star shone so brightly that it could be seen during the day. It stayed in view for well over a year, which meant that it couldn’t be a comet. It never changed its position against the backdrop of other stars, which meant that it had to be immensely far away. Nothing but a star had those properties. It was undeniable, and it was impossible.
Today every promising actor or athlete is a “new star,” and the cliché has lost its force, but the appearance of the first new star in the immutable heavens was shocking. Tycho proclaimed it “the greatest wonder that has ever shown itself in the whole of nature since the beginning of the world, or in any case as great as when the Sun was stopped by Joshua’s prayers.”
Unable to sort out its meaning, most observers labeled this aberration “Tycho’s star” and did their best to put it out of their minds. But in 1604, still another new star appeared, this one perhaps even brighter than its predecessor. Galileo, caught up in the excitement, delivered a public lecture on the new star to a standing-room-only crowd. The discovery of two new stars within three decades shocked the learned world. Stargazers knew the appearance of the night sky as intimately as coast dwellers know the sea. We miss the point if we downplay their astonishment. How could a star appear where no star could be? All Europe was as stunned as another group, on the other side of the Atlantic, at almost the same moment.
On the morning of September 3, 1609, a band of Indians fishing from dugout canoes just off present-day Manhattan saw something odd in the distance. At first, it was only clear that the strange object was “something remarkably large swimming or floating on the water, and such as they had never seen before.” These first witnesses raced to shore and recruited reinforcements. The object drew closer. The guesswork grew frenzied, “some [of the Indians] concluding it either to be an uncommon large fish or other animal, while others were of opinion it must be some very large house.” The mysterious object drew closer still and then halted, its huge white wings billowing. In fear and fascination, the Indians on shore and the sailors on the deck of Henry Hudson’s Half Moon stood staring at one another.
What was it like to see what no one had ever seen before?
In that same year of 1609, perhaps in May, Galileo heard talk of a Dutch invention, a lens maker’s device with the power to bring far-off objects into close view. By this time, reading glasses to compensate for farsightedness were centuries old. Glasses to help with nearsightedness were more recent but widely available, too. Lenses for farsightedness were convex, thick in the middle and thin at the edges (lentil-shaped, hence the word lens); lenses for nearsightedness were concave, thinner in the middle than at the edges. The breakthrough that made the telescope possible was to combine a convex lens with a concave one. Everything hinged on the proportion between the strengths of the two lenses, which called for difficult feats of grinding and polishing.
By the end of August, Galileo had built one of the sorcerer’s tubes for himself. It didn’t look like much—a skinny tube about a yard long made mostly from paper and wood, it resembled a tightly rolled poster—and it took a bit of fiddling to get the hang of seeing through it. Galileo unveiled it to a group of high-ranking Venetians. They took turns peering through his telescope and responded with “infinite amazement,” in Galileo’s proud words.
“Many of the nobles and senators, although of a great age, mounted more than once to the top of the highest church tower in Venice,” Galileo reported, “in order to see sails and shipping that were so far off that it was two hours before they were seen, without my spy-glass, steering full sail into the harbor.” The military advantages of such an invention were plain, but Galileo made sure that no one could miss them. The telescope, he pointed out, allows its users “to discover at a much greater distance than usual the hulls and sails of the enemy, so that for two hours and more we can detect him before he detects us.”
Galileo rocketed to fame. Thrilled by what they had seen, the senators immediately doubled his salary and awarded him a lifetime contract at Padua. (Galileo had helped his own cause by presenting the senators an elaborate telescope as a gift, this one no drab tube but an ornate instrument in red and brown leather decorated, like an elegant book, in gold filigree.)
Galileo’s decision to highlight the telescope’s value for warfare and commerce was cagey, but it was necessary, too. Galileo had grand ambitions. He knew from the start that the real discoveries would come from looking up to the stars, not out to sea. Which meant that the world had to be cajoled into believing that it could trust the sights revealed by this new, mysterious invention. In Rome, in 1611, he pointed his telescope at a palace far in the distance, and “we readily counted its each and every window, even the smallest.” With the telescope trained on a distant wooden sign, “we distinguished even the periods carvedbetween the letters.”
So the telescope provided honest information. It revealed true features of faraway objects; it didn’t somehow, through trickery or strange properties of light and lenses, conjure up mirages. If Galileo had simply aimed his telescope at the heavens, without preliminaries, skeptics might have dismissed the wonders he claimed to see. (Even so, some people refused to look, as today some might shy away from a purported ESP machine.)
Galileo continued to improve his design and soon produced a telescope able to magnify twenty times, twice as powerful as his first model. He could now be certain that the new stars that had appeared in 1572 and 1604 were the merest prelude, a two-note introduction to a visual symphony.
His own excitement fully matched that of the ecstatic senators in San Marco’s belltower. The “absolute novelty” of his discoveries, Galileo wrote, filled him with “incredible delight.” He marveled at the sight of “stars in myriads, which have never been seen before, and which surpass the old, previously known stars in number more than ten times.” The moon, the perfect disc of a thousand poets’ odes, “does not possess a smooth and polished surface but one rough and uneven and just like the face of the Earth itself, everywhere full of vast protuberances, deep chasms, and sinuosities.”
The Milky Way was not some kind of cosmic fog reflecting light from the sun or moon, as had long been speculated. A glance through the telescope would at once put an end to all “wordy disputes upon this subject,” Galileo boasted, and would leave no doubt that “the Galaxy is nothing else but a mass of innumerable stars planted together in clusters . . . many of them tolerably large and extremely bright, and the number of small ones quite beyond determination.”
Yet another discovery was the most important of all, guaranteed to “excite the greatest astonishment by far.” But even for Galileo the astonishment was slow in dawning. He had aimed his telescope at Jupiter and spotted several bright objects near the planet. The next day they were still there, but they had rearranged themselves. A few days later, another rearrangement. Some days there were four objects; some days only two or three. What could it mean?
Jupiter and nearby mysterious objects, as seen by Galileo
The answer, Galileo came to see, was that four objects were in orbit around Jupiter. “I have discovered four planets, neither known nor observed by any one of the astronomers before my time,” Galileo crowed. (He hurried to name the moons in honor of Cosimo de’ Medici, Grand Duke of Tuscany, who swallowed the bait with gusto.) Here was a planetary system in miniature, and not a diagram or a mathematical hypothesis but an observable reality. Jupiter’s moons were mini-Earths moving in orbit around a central body. Why could not the Earth itself be in orbit around a huge central body? And if the Earth, why not the other planets, too?
These were exhilarating, disorienting discoveries. The unsuspected vistas revealed by the telescope inspired a fair number of seventeenth-century thinkers to rejoice at this proof that God’s creation was truly without bounds. It was only fitting that an infinite God should have created an infinite universe. What could be “more splendid, glorious, and magnificent than for God to have made the universe commensurate with his own immensity?” asked the Royal Society’s Joseph Glanvill.
The gates to the cosmos had been thrown open, and optimists ran through and turned cartwheels in the vastness. “When the heavens were a little blue arch stuck with stars, methought the universe was too strait and close,” exulted the French writer Bernard de Fontenelle, in an immensely popular account of the new doctrines called On the Plurality of Worlds. “I was almost stifled for want of air; but now it is enlarged in height and breadth and a thousand vortexes taken in. I begin to breathe with more freedom, and I think the universe to be incomparably more magnificent than it was before.”24
But the endless expanses that beckoned so invitingly to some induced a kind of trembling agoraphobia in others. Pascal spoke for all who found themselves horrified by a vision of the planets as specks of dust adrift in a black immensity. “The eternal silence of these infinite spaces frightens me,” he observed, and he seemed to view humankind on its lonely voyage as akin to a ship’s crew adrift in an endless sea. “What is a man in the midst of infinity?” Pascal asked.
Decades before, Copernicus’s pushing of the Earth off center stage had inspired similar questions and similar fears, but among a smaller audience. Galileo had far more impact. Anyone could look through a telescope, while almost no one could follow a mathematical argument. But whether Copernicus or Galileo took the role of narrator, the story was the same. The Earth was not the center of the universe but a run-of-the-mill planet in a random corner of the cosmos.
This stripping away of Earth’s special status is always cited as a great assault on human pride. Freud famously contended, for example, that in the course of modern history three thinkers had dealt enormous blows to humankind’s self-esteem. The three were Copernicus, Darwin, and Freud himself. Darwin had proved that humans are animals, and Freud that we are blind to our own motivations. But the first body blow had come from Copernicus, who had displaced mankind from his place of honor.
Freud had a key piece of the story almost exactly backward. Before Copernicus and Galileo, humans had believed that they lived at the center of the universe, but in their minds the center was a shameful, degraded place, not an exalted one. The Earth was lowly in every sense, at the furthest possible remove from the heavens. Man occupied “the filth and mire of the world,” wrote Montaigne, “the worst, lowest, most lifeless part of the universe, the bottom story of the house.”
In the cosmic geography of the day, heaven and hell were actual places. Hell was not consigned to some vague location “below” but sat deep inside the Earth with its center directly beneath Jerusalem. The Earth was the center of the universe, and hell was the center of the center. Galileo’s adversary Cardinal Bellarmine spelled out why that was so. “The place of devils and wicked damned men should be as far as possible from the place where angels and blessed men will be forever. The abode of the blessed (as our adversaries agree) is Heaven, and no place is further removed from Heaven than the center of the earth.”
Mankind had always occupied a conspicuous place in the universe, in other words, but it was a dangerous and exposed position rather than a seat of honor. Theologians through the ages had thought well of that arrangement precisely because it did not puff up human pride. Humility was a virtue, they taught, and a home set amid “filth and mire” was nearly certain to have humble occupants.
In a sense, Copernicus had done mankind a favor. By moving the Earth to a less central locale, he had moved humankind farther from harm’s way. For religious thinkers, ironically, this was yet another reason to object to the new doctrine. Theologians found themselves contemplating a riddle—how to keep humanity in its place when its place had moved?
In time, they would come up with an answer. They would seize on a different aspect of the new astronomy, the vast expansion in the size of the universe. If the universe was bigger, then man was smaller. For theologians in search of a way to reconcile themselves to science’s new teachings, a doctrine that seemed to belittle mankind was welcome news.