God's Planet

Owen Gingerich

• Verlag: Harvard University Press
• Jahr: 2014
• ISBN:
  9780674745018
• Thema: Teología y religión
• Thema: Religión y ciencia

With exoplanets being discovered daily, Earth is still the only planet we know of that is home to creatures who seek a coherent explanation for the structure, origins, and fate of the universe, and of humanity's place within it. Today, science and religion are the two major cultural entities on our planet that share this goal of coherent understanding, though their interpretation of evidence differs dramatically. Many scientists look at the known universe and conclude we are here by chance. The renowned astronomer and historian of science Owen Gingerich looks at the same evidence—along with the fact that the universe is comprehensible to our minds—and sees it as proof for the planning and intentions of a Creator-God. He believes that the idea of a universe without God is an oxymoron, a self-contradiction. God's Planet exposes the fallacy in thinking that science and religion can be kept apart.Gingerich frames his argument around three questions: Was Copernicus right, in dethroning Earth from its place at the center of the universe? Was Darwin right, in placing humans securely in an evolving animal kingdom? And was Hoyle right, in identifying physical constants in nature that seem singularly tuned to allow the existence of intelligent life on planet Earth? Using these episodes from the history of science, Gingerich demonstrates that cultural attitudes, including religious or antireligious beliefs, play a significant role in what passes as scientific understanding. The more rigorous science becomes over time, the more clearly God's handiwork can be comprehended.

Nicolaus Copernicus (1473–1543). Portrait by Isaac Bullarts, Académie des Sciences, vol. 2, 1682.

1

Was Copernicus Right?

FOR MANY YEARS I have puzzled about the nature of science and its theoretical structures of explanation. What gives science the ability to make predictions? In 1705 Edmond Halley predicted that a bright comet he had observed in 1682 would return again in 1758, and if it happened, he said, he hoped that candid posterity would notice that it had first been predicted by an Englishman. He was lampooned for placing the date of the comet’s return well after his lifetime, so he would not have to face public scorn for such a ridiculous prognostication. But the comet did return and has borne his name ever since.

And there have been many later astronomers who envisioned planets around many distant stars, though they had little hope of actually verifying this. Today, with the recent Kepler mission, direct evidence for this prediction has been attained for nearly a thousand extrasolar planets, or exoplanets, as they are called. In another field, biologists have concluded that the ancestors of whales lived on the land, and today paleontologists have found hundreds of skeletons of early whales that still have vestiges of legs. Or in physics, we have all heard of the massive search for the so-called Higgs boson, which was predicted to exist and was finally found this past year.

This uncanny ability to make such a coherent picture of the physical and biological world has now allowed science to reign at the top of the tree of knowledge. This has not always been the case. Five centuries ago in Western civilization theology was considered the queen of the sciences, that is, the queen of knowledge. So what is the epistemological relationship between science and theology today? Are they separate magisteria, each going its own way, entirely unrelated? This is a major puzzle, and one I do not expect to resolve. Nevertheless, it is a central puzzle that I hope to address in these chapters, gradually circling around the issues from a historical perspective.

The theme of this first chapter is “Was Copernicus right?” Nicolaus Copernicus was of course the Polish astronomer who introduced the earthshaking heliocentric cosmology. When this first chapter was presented as a lecture, I remarked that presumably nearly everyone in the audience would agree that his cosmology was right. A few might have suspected that I had a perverse reason to answer “no” and a few others may very well have hoped that I would simply say “yes, he was right” and sit down. Either response would of course have led to a scandal, and the audience wouldn’t have wanted to miss that.

But then again, if Copernicus’s cosmology was right, why did it take a century and a half before a majority of educated people accepted the idea that the Earth moved and the Sun stood still? So that is the particular puzzle facing us. First we should look briefly at the astronomy involved and then at the cultural and theological milieu into which it was thrown.

Let me begin by introducing Copernicus. He was a contemporary of Columbus and of Martin Luther, two other personalities who reshaped our world views. Young Nicolaus came under the patronage of his maternal uncle, who was making great strides in ecclesiastical politics, and who became bishop of Varmia, the northernmost Catholic diocese in Poland, a post in authority and power comparable to being governor of the province. Nicolaus was elected a canon of the Frombork Cathedral in Varmia, which meant that he was one of the sixteen members of the cathedral chapter, that is, its board of directors. Never ordained as a priest, he nevertheless took minor orders and had charge of one of the cathedral altars. His uncle sent him to Italy to study law and medicine, two areas of interest to the diocese. As a graduate student in Italy, Copernicus was in Bologna on the same day as Leonardo da Vinci, though it’s unlikely that the eminent artist met the aspiring young canon lawyer.

Even as an undergraduate in Cracow, Copernicus had taken a keen interest in the stars and planets, and had armed himself with a few basic books in astronomy. Remember that the printing of books was not even fifty years old; had Copernicus lived a century earlier, it would have been far more difficult to obtain the sources he needed for his reform of astronomy. While in Italy he boarded at the home of Domenico Maria Novara, the university’s astronomer, and while there he made some of his earliest preserved observations.

Frombork Cathedral in the northernmost Catholic diocese in Poland, where Copernicus worked as a lawyer and medical doctor. In the distance is the Vistula Lagoon, brackish waters separated from the Baltic Sea by a narrow spit of land. Photograph by Paul Gander.

The astronomy that Copernicus studied at Cracow and then in Italy was geocentric, that is, with the Earth firmly fixed in the center of the cosmos. Now today, if we wanted to calculate the position of Mars with a very rough approximation, we could use two circles, one for the orbit of Mars around the Sun and the other for the orbit of the Earth around the Sun, and we could connect them with some simple trigonometry. In Copernicus’s day, using astronomy based on the ancient Ptolemaic system, there were also two circles, one going around the fixed Earth and the other, called an epicycle, riding on the first circle. From the point of view of geometry, the basic calculation was the same, whether you used the Sun as the center or used the Earth as your fixed reference point. The goal was identical, to know where to look for Mars as seen from the Earth. It was just mathematics, one way or the other.

But now suppose you are a student at the Jagiellonian University in Cracow in 1492, and someone came along and told you that the Sun is really a lot bigger than the Earth, and therefore the Sun, not the Earth, should be at the center of the universe, and furthermore, it didn’t make any sense for the entire cosmos to spin around the Earth every day. You would no doubt have told him to get lost and to take all that nonsense with him. If the Earth was whizzing around the Sun, and spinning on an axis every day, a thousand miles an hour, we would surely just be spun off into space. And think how much harder it would be to walk west than to walk east! Totally ridiculous!

The goal of the planetary model is to find the direction to a planet in the sky, the line EM from Earth to Mars in either model. The diagram shows the simplified “kindergarten” model, without variations of speed, for example, but the important point is that the complexity is the same in either model. The triangle ESM is identical in both models. It was long known that the direction of the radius in the geocentric epicycle was always parallel to the direction to the Sun. After constructing the parallelogram, Copernicus realized that he could place the Sun at the upper-left corner of the parallelogram (as shown here) and then link all of the planets into a unified Sun-centered system.

When I described Copernicus’s heliocentric cosmology as earthshaking, the adjective was deliberately chosen, for not only did it defy common sense, but it was soon to run up against Psalm 104: “The Lord God fixed the Earth on its foundation so that it can never be shaken.” For all these reasons, Copernicus was very reluctant to publish his radical ideas, although he had spent years not only working through all the mathematics, but also assembling the specific observations he needed. He was able to show that some of the parameters describing the planetary motions had changed slightly since the days of Ptolemy and some had remained the same, yet they could all be fit into a Sun-centered system. But Copernicus, as he himself put it, feared that he would be hissed off the stage.¹

There the matter rested as Copernicus neared the age seventy, when, remarkably, a young teacher from the Protestant university in Wittenberg, Georg Joachim Rheticus, turned up on his doorstep, begging to learn what Copernicus has accomplished. Rheticus’s visit, intended to last a few days, soon extended to weeks, then months, and finally to over two years. He persuaded Copernicus to publish, and eventually took the precious manuscript to Nuremberg, where it was finally printed in 1543 under the title De revolutionibus orbium coelestium, or On the Revolutions of the Heavenly Spheres. Copernicus himself received the final pages on his death bed. It was a hefty tome of 400 pages, rivaling Ptolemy’s Almagest, the only comparable treatise.

So, what was its impact?

Let me reset the clock from Germany in 1543 to the British Isles in 1970 and invite you to join me on a school-holiday family trip from Cambridge, England, where I was on a sabbatical leave. En route to Edinburgh, Scotland, we stopped in York so I could consult with a colleague, Jerry Ravetz, who like me was on the committee to plan the forthcoming international celebrations for the five-hundredth anniversary of Copernicus’s birth in 1473. And we asked ourselves that very question, what was impact of Copernicus’s De revolutionibus?

Now, a dozen years earlier, the German-American novelist Arthur Koestler had published a history of astronomy entitled The Sleepwalkers. As he later confessed, he had been upset by the fact that virtually all German schoolboys knew the name of the Italian Galileo, but few could identify Johannes Kepler, the German astronomer who had discovered the elliptical form of the planetary orbits.² So he deliberately set out to write a book to redress the balance. As a novelist, he was prone to see the world in terms of good guys and bad guys, and thus in The Sleepwalkers Kepler was given the role of good guy and Copernicus and Galileo were the bad guys. In particular, he branded De revolutionibus as “the book nobody read” and “an all-time worst seller.”³

On that evening in York, Ravetz and I asked ourselves who might have read Copernicus’s book in the sixteenth century, and we counted fewer than a dozen names before we ran out of ideas. And then our conversation drifted off to other matters.

In Scotland two days later, while Miriam and our sons explored the Edinburgh castle, I delved into the fabulous collection of rare astronomy books at the Royal Edinburgh Observatory, and there I discovered something truly astonishing. It was not just a first edition of De revolutionibus, but a copy filled with marginal annotations by a reader who worked his way through the entire opus, highlighting key passages, explicating complex sections, and finding a scattering of small errors. If this book had so few readers, what was my chance that the very next copy I saw would bear the weight of heavy and perceptive reading? It just didn’t add up.

With a pounding heartbeat I looked for clues to the identity of the annotator, and eventually noticed impressed into the binding the initials E and R. “Jackpot!” I thought, for these matched a name from our list of probable readers, Erasmus Reinhold, the senior professor of astronomy at Wittenberg, colleague of Rheticus, and a leading astronomical pedagogue of the sixteenth century. In my excitement I grabbed a sheet of paper and made a rubbing of the initials on the binding. ERS appeared on the sheet. Wait a minute! Where did that S come from? That let all of the air out of my balloon!

With respect to early books, I was then a mere adolescent, but I was a fast learner, and it was only a matter of days for me to find out that ERS was exactly what I should have expected, for in those days the town of one’s birth was part of one’s identity. Erasmus Reinholdus Salveldiensis was the Wittenberg professor’s full appellation, and the mysterious S stood for Saalfeld, the town of his birth.

The serendipitous discovery of Reinhold’s richly annotated copy of De revolutionibus provided a window into the way a skilled sixteenth-century astronomer looked at Copernicus’s unorthodox cosmology—in fact, he essentially ignored it!—but more of that in a moment. Finding this spectacularly annotated book ignited a quest to see what the margins of other copies might contain, a possibly quixotic search to examine all possible surviving sixteenth-century examples of De revolutionibus, a series of globe-trotting journeys extending over thirty-five years and tens of thousands of miles. One result was a detailed census of 600 copies, and the other was a memoir ironically entitled The Book Nobody Read, whose last words are, “Arthur Koestler was wrong, dead wrong!”⁴ In other words, every astronomer who took his occupation seriously was very likely to have had and to have read a copy of De revolutionibus.

Still, Arthur Koestler was a clever, educated man. How could he have been so wrong? And this is part of our puzzle, the very long time it took for a majority of educated persons to accept the heliocentric cosmology.

An overwhelming majority of us agree that it is the Earth going around the Sun and not vice versa. We know the Sun is a mass of incandescent gas, very different from the planets arrayed around it, or as Copernicus put it in his soaring cosmological chapter, “the sun, seated on a royal throne, governs the family of ...