Coming of Age in the Milky Way
Page 1
COMING
OF AGE
IN THE
MILKY
WAY
TIMOTHY FERRIS
For Carolyn
If I could write the beauty of your eyes
And in fresh numbers number all your graces,
The age to come would say, “This poet lies—
Such heavenly touches ne’er touched earthly faces.”
—SHAKESPEARE
PREFACE TO THE
PERENNIAL EDITION
If, as is often suggested, writing a book is like giving birth, publishing a book is like watching one’s child graduate from college. The author hopes that the book will have a healthy life of its own, going off into the world and requiring little more in the way of parental help or guidance. The longer the book fares well, the less the author matters: Such is the apt, implicit bargain struck by parents with their children, and authors with their books.
This author has had occasion to feel proud of this child. During the fifteen years since its publication, Coming of Age in the Milky Way has made its way on sturdy legs. Critics have been kind to it, professors have taught it, and readers around the world have proved gratifyingly loyal to it.
So why, now, is the author injecting himself back into its affairs, like a father preposterously hogging the spotlight at his daughter’s wedding?
Principally because fifteen years is a long time in astronomy and cosmology, during which new and exciting things have happened. Some readers—the professors especially—have asked if a new edition might not be prepared, to update the unfolding story of humanity’s investigations into the nature of space and time. So here it is.
Few revisions have been required to the original book, except to correct a handful of typographical errors and authorial infelicities. Fevered newspaper headlines to the contrary, established sciences nowadays seldom undergo “revolutions” that oblige researchers to “rethink their basic notions” about the cosmos. There have, however, been several genuine surprises, some of which have profound potential consequences. Cosmology appears to be entering a new era, characterized both by a greatly improved ability to probe the history and evolution of the universe and by startling discoveries that open up exciting new vistas on the cosmos. This news of the universe is reported in the Addendum to this new edition, beginning on page 389.
The best news is that human knowledge of time and space continues to expand, shining like a brightening beacon in a world still benighted by ignorance and by the fear, rage, and greed that ignorance fosters. When tempted to curse the darkness we do well to remember that the circle of light is growing. Tending to it are many heroes, ranging from celebrated scientists to unsung teachers whose students may, in time, light a few lamps of their own. Without them, books like this one could not be written.
PREFACE
AND
ACKNOWLEDGMENTS
How oft we sigh
When histories charm to think that histories lie!
—Thomas Moore
This book purports to tell the story of how, through the workings of science, our species has arrived at its current estimation of the dimensions of cosmic space and time. The subject is grand, and it goes without saying that the book is unequal to it. Of the limitations and liabilities of this work I would hope to defend only those resulting from its brevity. Obedient to the dictum of Callimachus that “a big book is equal to a big evil,” I have striven for economy, but economy has its price.
First, it has of course meant leaving out many things. In a general survey of science it would be ludicrous, for instance, to discuss quantum mechanics without making reference to Erwin Schrödinger, who was one of the principal architects of that innovative and fruitful discipline. My justification is that this is not a general survey. It is a book with one tale to tell—that of the awakening of the human species to the spatiotemporal dimensions of the universe—and owes its loyalties to that theme alone.
In addition to encouraging sins of omission, compression tends to foreshorten history, making it seem more coherent and purposeful than it really is, or was. The real history of science is a maze, in which most paths lead to dead ends and all are littered with the broken crockery of error and misconception. Yet in this book all that is underrepresented, while disproportionate emphasis is devoted to the ideas and observations that have in retrospect proved most salient. A book that assigned a full measure of devotion to the mistakes of science would, however, be almost unreadable: Plowing through it would be like reading a collection of mystery stories of which only one or two came to any satisfactory resolution, while in most the detective switched careers before the identity of the culprit could be ascertained or the butler was irrelevantly run over by a bus.
Similarly, in recounting the long-term development of enduring conceptions one tends to assign missions to people that they did not have, or did not know that they had, at the time. Thus Maxwell becomes the father of unified theory, Fraunhofer a founder of astrophysics, and Einstein the theorist who anticipated the expansion of the universe, though there is no evidence that any of these men ever got up in the morning with the intention of doing any such thing. As Thomas Carlyle wrote, “No hammer in the Horologe of Time peals through the universe when there is a change from Era to Era. Men understand not what is among their hands.”1 But history, as they say, is comprehended backward though it must be lived forward, and when we examine our predecessors we bring our own lamps.
Economy also implies simplification. This book is intended for general readers. It keeps mathematics and jargon to a minimum—such technical terms as seemed unavoidable are explained in the text and the glossary—and in so doing sometimes warps the very concepts it seeks to explain. Where the distortion is excessive or ill-advised the fault is of course entirely my own, but much of it results from a change of perspective: Relativity and quantum mechanics and cosmology look different to a lay observer than to a practicing scientist, just as the experience of making an Atlantic crossing on a cruise ship is different for a passenger than for a stoker in the boiler room. On the other hand, I have tried in general not to oversimplify, preferring that a subtle idea remained subtle in the retelling rather than hammering it so flat as to make it appear trivial or self-evident.
Much the same applies when it comes to ambiguities and disagreements over the facts of our intellectual heritage and their interpretation. The history of science is full of disputations about such questions as just why Galileo was persecuted by the Roman Catholic Church or whether Einstein had the Michelson-Morley experiment in mind when he composed his special theory of relativity. Having tiptoed through more than a few of these minefields, I am full of admiration for scholars who choose to habituate them. Nevertheless, I have devoted little space to detailing the contrasting arguments they have set forth. If the resulting narrative is unambiguous it is also skewed, and can claim to be accurate only insofar as I may have succeeded in supporting or inventing a point of view that may itself prove to be accurate. Here endeth the confession, with the plea that economy is a jealous god.
A word about numerical style. Exponential numbers are employed, in which the exponents express powers of ten; thus 10skies of our ancestors hung−3 equals a one followed by three zeros, or 1,000, and 10−3 equals 0.001. By the word “billion” is meant the American billion, equal to 1,000,000,000 or 109.
Coming of Age in the Milky Way was written in New York, Los Angeles, and San Francisco over a period of twelve years, from 1976 through 1988. As one might expect, in the course of so long a project I have incurred more debts of gratitude than I can properly retire. I should like, however, to express my thanks for aid and criticism provided by William Alexander, Sh
erry Arden, Hans Bethe, Nancy Brackett, Ken Broede, Robert Brucato, Lisa Drew, Ann Druyan, David Falk, Andrew Fraknoi, Murray Gell-Mann, Owen Gingerich, J. Richard Gott III, Stephen Jay Gould, Alan Guth, Stephen Hawking, He Xiang Tao, Karen Hitzig, Larry Hughes, Res Jost, Kathy Lowry, Owen Laster, Irwin Lieb, Dennis Meredith, Arthur Miller, Bruce Murray, Lynda Obst, Heinz Pagels, Abraham Pais, Thomas Powers, Carl Sagan, Allan Sandage, David Schramm, Dennis Sciama, Frank Shu, Erica Spellman, Gustav Tammann, Jack Thibeau, Kip S. Thorne, Michael Turner, Nick Warner, Steven Weinberg, John Archibald Wheeler, Houston Wood, and Harry Woolf.
I am grateful to Prairie Prince for the line illustrations that accompany the text. For research aid and secretarial assistance at various stages along the way I am indebted to Eustice Clarke, Dave Fredrick, Russ Gollard, Michele Harrah, Sandra Loh, and Camille Wanat, and to the exertions of librarians too numerous to mention at the American Institute of Physics, Brooklyn College of the City University of New York, CERN, Caltech, the Federal Polytechnic Institute in Zurich, Fermilab, Harvard University, the Massachusetts Institute of Technology, the Mount Wilson and Las Campanas Observatories, New York University, Princeton University, the University of Southern California, the University of California at Berkeley, and the public libraries of New York City, Los Angeles, Chicago, Boston, and Miami.
I am happy to acknowledge the support provided by research grants from the University of California at Berkeley, the Division of Social Sciences of the University of Southern California, and the John Simon Guggenheim Memorial Foundation.
My thanks go as well to my mother, Jean Baird Ferris, for her lively conversation and steadfast encouragement, her tireless proffering of intriguing clippings and articles, and for having taught me, as a boy, to love and to live by books.
Finally I should like to express my gratitude to my wife and family, for their loving and generous forbearance through the long years of long hours that writing this book consumed.
—T.F.
Berkeley, California
CONTENTS
PREFACE TO THE PERENNIAL EDITION
PREFACE AND ACKNOWLEDGMENTS
ONE: SPACE
1. THE DOME OF HEAVEN
2. RAISING (AND LOWERING) THE ROOF
3. THE DISCOVERY OF THE EARTH
4. THE SUN WORSHIPERS
5. THE WORLD IN RETROGRADE
6. NEWTON’S REACH
7. A PLUMB LINE TO THE SUN
8. DEEP SPACE
9. ISLAND UNIVERSES
10. EINSTEIN’S SKY
11. THE EXPANSION OF THE UNIVERSE
TWO: TIME
12. SERMONS IN STONES
13. THE AGE OF THE EARTH
14. THE EVOLUTION OF ATOMS AND STARS
THREE: CREATION
15. THE QUANTUM AND ITS DISCONTENTS
16. RUMORS OF PERFECTION
17. THE AXIS OF HISTORY
18. THE ORIGIN OF THE UNIVERSE
19. MIND AND MATTER
20. THE PERSISTENCE OF MYSTERY
ADDENDUM TO THE PERENNIAL EDITION
GLOSSARY
A BRIEF HISTORY OF THE UNIVERSE
NOTES
BIBLIOGRAPHY
INDEX
About the Author
Books by Timothy Ferris
Copyright
About the Publisher
One thing I have learned in a long life: that all our science, measured against reality, is primitive and childlike—and yet it is the most precious thing we have.
—Albert Einstein
The wind was flapping a temple flag, and two monks were having an argument about it. One said the flag was moving, the other that the wind was moving; and they could come to no agreement on the matter. They argued back and forth. Eno the Patriarch said, “It is not that the wind is moving; it is not that the flag is moving; it is that your honorable minds are moving.”
—Platform Sutra
PART ONE
SPACE
The self shines in space through knowing.
—The Upanishads
1
THE DOME OF HEAVEN
You may have heard the music of Man but not the music of Earth. You may have heard the music of Earth but not the music of Heaven.
—Chuang Tzu
Had we never seen the stars, and the sun, and the heaven, none of the words which we have spoken about the universe would ever have been uttered. But now the sight of day and night, and the months and the revolutions of the years, have created number, and have given us a conception of time, and the power of enquiring about the nature of the universe; and from this source we have derived philosophy, than which no greater good ever was or will be given by the gods to mortal man.
—Plato
The skies of our ancestors hung low overhead. When the ancient Sumerian, Chinese, and Korean astronomers trudged up the steps of their squat stone ziggurats to study the stars, they had reason to assume that they obtained a better view that way, not, as we would say today, because they had surmounted a little dust and turbulent air, but because they had got themselves appreciably closer to the stars. The Egyptians regarded the sky as a kind of tent canopy, supported by the mountains that demarked the four corners of the earth, and as the mountains were not all that high, neither, presumably, were the heavens; the gigantic Egyptian constellations hovered close over humankind, as proximate as a mother bending to kiss a sleeping child. The Greek sun was so nearby that Icarus had achieved an altitude of only a few thousand feet when its heat melted the wax in his wings, sending the poor boy plunging into the uncaring Aegean. Nor were the Greek stars significantly more distant; when Phaethon lost control of the sun it veered into the stars as suddenly as a swerving chariot striking a signpost, then promptly rebounded to earth (toasting the Ethiopians black on its way down).
But if our forebears had little notion of the depths of space, they were reasonably well acquainted with the two-dimensional motions of the stars and planets against the sky, and it was by studying these motions that they were led, eventually, to consider the third dimension as well. Since the days of the ancient Sumerians and probably before, there had been students of the night sky willing to devote their evening hours to the lonely business of squinting and straining to take sightings over aligned rocks or along wooden quadrants or simply across their fingers and thumbs, patiently keeping records of what they saw. It was a lot of trouble. Why did they bother?
Part of the motive may have had to do with the inchoate longing, mysterious but persistent then as now, to express a sense of human involvement with the stars. As Copernicus noted, reverence for the stars runs so deep in human consciousness that it is embedded in the language itself. “What is nobler than the heavens,” he wrote, “the heavens which contain all noble things? Their very names make this clear: Caelum (heavens) by naming that which is beautifully carved; and Mundus (world), purity and elegance.”1 Even Socrates, though personally indifferent toward astronomy, conceded that the soul “is purified and kindled afresh” by studying the sky.
There were obvious practical incentives as well. Navigation, for one: Mariners could estimate their latitude by measuring the elevation of the pole star, and could tell time by the positions of the stars, and these advantages were sufficiently appreciated that seafaring peoples codified them in poetry and mythology long before the advent of the written word. When Homer says that the Bear never bathes, he is passing along the seafarer’s knowledge that Ursa Major, the constellation that contains the Big Dipper, is circumpolar at Mediterranean latitudes—that is, that it never sinks beneath the ocean horizon.
Another practical motive was timekeeping. Early farmers learned to make a clock and a calendar of the moving sky, and consulted almanacs etched in wood or stone for astronomical guidance in deciding when to plant and harvest their crops. Hesiod, one of the first poets whose words were written down, emerges from the preliterate era full of advice on how to read the sky for clues to the seasons:
When great Orion rises, set your slav
es
To winnowing Demeter’s holy grain
Upon the windy, well-worn threshing floor….
Then give your slaves a rest; unyoke your team.
But when Orion and the Dog Star move
Into the mid-sky, and Arcturus sees
The rosy-fingered Dawn, then Perseus, pluck
The clustered grapes, and bring your harvest home….
When great Orion sink, the time has come
To plough; and fittingly, the old year dies.2
The hunter-gatherers who preceded the farmers also used the sky as a calendar. As a Cahuilla Indian in California told a researcher in the 1920s:
The old men used to study the stars very carefully and in this way could tell when each season began. They would meet in the ceremonial house and argue about the time certain stars would appear, and would often gamble about it. This was a very important matter, for upon the appearance of certain stars depended the season of the crops. After several nights of careful watching, when a certain star finally appeared, the old men would rush out, cry and shout, and often dance. In the spring, this gaiety was especially pronounced, for … they could now find certain plants in the mountains. They never went to the mountains until they saw a certain star, for they knew they would not find food there previously.3