Venus in Transit

VENUS IN TRANSIT

✶

PATHS OF VENUS

(MOST NORTHERLY, CENTRAL, AND MOST SOUTHERLY)

ACROSS THE SUN’S FACE

DURING THE TRANSITS OF A.D. 1631, 1639, 1761, 1769, 1874, 1882, 2004, AND 2012.

VENUS IN TRANSIT

Eli Maor

✶

PRINCETON UNIVERSITY PRESS

PRINCETON AND OXFORD

Copyright © 2000, 2004 by Princeton University Press

Published by Princeton University Press, 41 William Street,

Princeton, New Jersey 08540

In the United Kingdom: Princeton University Press,

3 Market Place, Woodstock, Oxfordshire OX20 1SY

All Rights Reserved

This paperback is an expanded edition of June 8, 2004: Venus in Transit, originally published in hardcover in 2000 by Princeton University Press

Library of Congress Cataloging-in-Publication Data has been applied for

ISBN 0-691-11589-3

eISBN 978-0-691-22535-7

Excerpts from Transit of Earth, in The Wind from the Sun: Stories of the Space Age, © 1972 by Arthur C. Clarke, reprinted

by permission of Harcourt, Inc.

British Library Cataloging-in-Publication Data is available

pup.princeton.edu

R0

In memory of my grandparents,

Frida and Karl Stiefel

CONTENTS

PREFACE ix

PROLOGUE 3

CHAPTER 1. The Dreamer 7

CHAPTER 2. Dawn of a New Cosmology 15

CHAPTER 3. A Sight Never Seen Before 23

CHAPTER 4. Venus Stripped Bare 30

Solar and Stellar Parallax 44

CHAPTER 5. The Dance of Two Planets 51

CHAPTER 6. A Call for Action 67

CHAPTER 7. Venus Returns 77

CHAPTER 8. A Second Chance 92

CHAPTER 9. The Next Two Appointments 111

Father Hell: Falsely Accused 126

Afterthoughts 134

CHAPTER 10. Transits of Fancy 140

CHAPTER 11. A View from Other Worlds 150

Toward Distant Suns 158

A Personal Pilgrimage 162

CHAPTER 12. June 8, 2004 165

APPENDIXES

1. Halley’s Method 175

2. Times of the Transit of June 8, 2004, for Some Major Cities 180

3. Dates of Some Past and Future Transits 181

BIBLIOGRAPHY 185

ILLUSTRATION CREDITS 189

INDEX 191

PREFACE

CHILDHOOD memories often last a lifetime. When I was four or five years old, my grandmother used to take me out after dinner on Saturday night to watch for the first three stars visible in the evening sky, the moment when, according to Jewish tradition, Shabbat ends. Tel Aviv in those days was a small town, not yet awash in light as most cities are today, and one could still enjoy a fairly clear view of the heavens. I remember my pride when I was able to see those first three stars in the fading glow of dusk! Later she bought me a star map, one of those revolving contraptions where the constellations, etched in white against a dark-blue background, were visible through an oval-shaped window; as you rotated the map and set it to the right day and hour, the entire sky would unfold before you, revealing a miniature image of the universe.

On the night of March 3, 1942, Tel Aviv was treated to the spectacle of a total lunar eclipse. My grandfather prepared me for the event, and with great anticipation the two of us waited for the show to begin. And lo and behold, at the precise predicted moment you could see a small dark notch biting into the full moon. We watched in fascination as Earth’s shadow slowly covered the lunar disk, until the entire moon was immersed in darkness, leaving a dim, reddish, ghostly sphere hanging in the sky. What impressed me most, however, was not the event itself but its predictability, the fact that someone could foresee with absolute certainty a heavenly event taking place more than 200,000 miles away—the moon’s entrance into earth’s shadow.* My grandfather then told me the story of Christopher Columbus, who, when the natives refused to give his men food and water, warned them that God will punish them by taking away the moon’s light. His admonition was at first ridiculed, but when at the appointed time the moon’s light began to fade, they repented and fell into submission. So, astronomical events not only could be predicted, they could also be put to good use.

Other stories followed: Galileo’s defiant exclamation, But it doeth move! at the end of his trial by the Roman Inquisition for his belief in the Copernican system, left a deep impression on me. Later I learned that he didn’t actually say these words, as the records of the trial show. I also learned that the story about Galileo dropping stones from atop the Leaning Tower of Pisa may not have been true either; and that Newton may never have seen the famous apple fall from the tree. Never mind; these stories were too beautiful to be dismissed!

Out of these early impressions grew a passion for things astronomical. I read every astronomy book I could lay my hands on. The stories of total solar eclipses, with photos showing the black moon completely covering the solar disk, leaving only the pearly corona in sight, made me determined to one day witness this grand spectacle with my own eyes. But the moon’s shadow was not to pass over the Holy Land for another hundred years, so I knew I had to go wherever else an eclipse would be visible. My chance came on February 26, 1979, when I took my wife and our two small children on a two-day trip to Montana. On the night before the eclipse, we drove through a blinding snowstorm, and our hopes dimmed. But Eclipse Day dawned bright and clear, and we saw the event from beginning to end. A spectacular sight it was, worth the long trip.

I was also left with some nonastronomical memories from that event. In describing past eclipses, writers have often commented on the eerie silence during totality, when not only humans but all of nature seems to be awestruck by the grand heavenly spectacle. But during this particular eclipse, someone decided that the excitement of the event itself was not enough: at the instant totality began, the town s sirens went off, as if to announce the arrival of an imminent disaster. I tried to ignore this distraction when I noticed another peculiarity: we were stationed near a major highway, and heavy trucks were rolling by at the crucial moment. I could not imagine how someone could just keep driving and not stop to watch this once-in-a-lifetime experience. But perhaps in the eyes of those truck drivers, we were the real oddballs, having traveled 1,500 miles to watch two and a half minutes of darkness.

The appetite comes with eating, says an old proverb. This first total eclipse created in me an urge to read every piece of eclipse literature I could get hold of. Before I knew it, I became an eclipse addict, willing to spend time and money to chase the moons shadow whenever and wherever it crossed our planet. Then one day I read in an old astronomy book that on June 8, 2004, the planet Venus will pass in front of the sun, making itself visible as a small black circle slowly moving across the solar disk. A strange eclipse of sorts! But when I searched for literature on this rarest of heavenly events, I found very little, most of it written more than a hundred years ago for the previous transit of Venus. Thus the present book was conceived.

Only five times before have humans witnessed the passage of Venus in front of the sun. The last transit was in 1882, and in our lifetime only two will present themselves. The rarity of the event, combined with the incredible misfortunes that befell some of the scientists who tried to observe it, gives the story all the elements of a true drama.

With the layperson in mind, I have limited the use of technical terminology to a bare minimum. I have, however, amply quoted from primary sources to preserve the spirit of the words in their original. I hope that the story told here will recapture some of the excitement that the five past Venus transits have evoked in all those who saw them.

The paperback edition of this book has two new sidebars: one on the recent news that an extrasolar planet has, for the first time, been observed transiting its parent star, and the other on my trip to Manchester, England, and the village of Much Hoole, where Jeremiah Horrocks observed the historic transit of Venus in 1639, the first ever seen. I have also added several new references that became available to me since the first edition was published, resulting in an expanded bibliography.

In the hardcover edition I thanked our son Eyal for designing the line drawings for this book. To our deep sorrow, he passed away on April 26, 2000, after a short battle with cancer. We miss him dearly.

Special thanks go to Helene Auer for translating some of Camille Flammarion’s reports of the 1882 transit from the French; to Joe Rao of the Hayden Planetarium and Cablevision’s News 12, New York, and to Jack Zirker, former head of the National Optical Astronomical Observatory, for their careful reading of the manuscript and their very useful suggestions; to Fred Espenak of NASA’s Goddard Space Flight Center for providing me with updated times for the 2004 transit; to Reny O. Montandon for sending me some hard-to-find publications on past transits of Venus; to Avi Varkowitzky for helping me plan my visit to the village of Much Hoole, England; to the staff of Princeton University Press for their care and dedication in preparing the work for print; to the Skokie and Morton Grove Public Libraries, whose staff greatly helped me in locating rare and out-of-print sources; and last but not least, to my dear wife, Dalia, for her continued encouragement and useful comments as the book was taking shape.

A NOTE ABOUT UNITS

Because much of the literature on transits was written by Englishmen, solar-system distances are given in this book in miles, rather than kilometers. I avoided the common but annoying practice of giving distances in both units, trusting that the reader can make the conversion to kilometers by multiplying by 1.609, a fairly close approximation for most practical purposes.

A NOTE ABOUT SPELLING

There is a tendency among modern authors to capitalize the words for all solar-system objects, including the sun, earth, and moon. I have capitalized these words only when they specifically refer to astronomical objects. For example, the view from planet Earth, but a transit of Venus as seen from the earth. When quoting, I have, of course, kept the original spelling.

September 15, 2003

* I was able to identify the date of this eclipse with the help of Fred Espenak’s Fifty Year Canon of Lunar Eclipses: 1986–2035 (NASA Reference Publication 1216, March 1989).

VENUS IN TRANSIT

✶

Prologue

JERUSALEM, Tuesday, June 8, 2004. The sun has just risen over the barren hills of the Judean Desert to the east, where, on a clear day, one can see the Dead Sea and the Moab Mountains beyond. From atop a tall minaret in the Moslem Quarter of the walled Old City, the muezzin’s monotonous, melancholic chant is already calling the faithful for their morning prayer. In the adjacent Christian Quarter, a lonely church bell chimes in the distance. And in the Jewish Quarter, pious Jews in their black garb solemnly walk down a narrow alley leading to the Western Wall, the sole remnant of King Herod’s mighty Temple, where they will pray in devotion, as Jews have done every day for the past two thousand years. In another hour or two, throngs of shoppers and tourists will fill the Old City’s narrow alleys, lined up with countless bazaars, small coffeehouses, crafts stores, and souvenir shops. The air will be saturated with the inviting fragrance of spices, the smell of produce and meat, and the aroma of freshly baked bread and pita. Another hot summer day in this 3,000-year-old city is about to begin.

But for several hundred people, gathered on the high ridge of Mount Scopus overlooking the city from the east, this will be anything but just another day. Below them to the west, a breathtaking panorama of the city has just unfolded, dominated by the golden Dome of the Rock glittering in the first rays of sunlight. From this very ridge, the Roman legions under Titus’s command lay siege to Jerusalem in a.d. 68, to be followed by the Crusaders, the Mamluks, the Turks, the British, the Jordanians, and the Israelis. From this ridge, countless pilgrims followed Jesus’ last journey down the Via Dolorosa into the walled city; it was here, one mile to the south, that Jesus was tried and imprisoned. Kings and statesmen stood in awe at this very place, taking in the sights and sounds surrounding them. Kaiser Wilhelm II of Germany came here on a royal visit in 1898; Winston Churchill, then the British colonial secretary, followed in 1921, and Albert Einstein gave here his inaugural address at the ceremonies opening the Hebrew University of Jerusalem in 1923, his first and only speech in Hebrew.

But the group of people gathered here today are directing their gaze not westward but to the rising sun in the east; their thoughts, at least for now, are not about the 3,000 years of history surrounding them, but on the immediate future before them. They came here from all over the world to witness a once-in-a-lifetime heavenly spectacle. Their cameras and telescopes, carefully covered with protective filters, are already aimed at the rising sun. Last-minute adjustments are made in a hurry, the equipment is checked and rechecked for any possible glitches, and everyone is anxiously listening to the latest weather forecast, hoping and praying that an unexpected cloud will not block the sun at the last minute. But so far the sky has been clear, as it usually is at this time of the year.

As the minutes tick by, a sense of expectation settles over the group. Time passes: it is 7:30 in the morning, then 8:00. Now the tension is almost unbearable. In just a few minutes these people, like many others at locations as far away as China and Australia, will witness a sight seen by humans only five times before. At precisely 8:19 A.M., a tiny notch, barely visible at first, is seen entering the eastern edge of the solar disk. A loud shout spontaneously erupts from everyone’s throat: first contact! In the next few minutes the notch slowly encroaches on the sun’s face, and the shape of a small black circle clearly makes itself apparent. The spectators are glued to their instruments. Clocks tick, cameras click, and in a few more minutes the black circle will be totally immersed in the sun’s disk: second contact. It is 8:38 A.M.

The tension