Billions And Billions

BILLIONS AND BILLIONS
Thoughts on Life and Death at the Brink of the Millennium

CARL SAGAN
BALLANTINE BOOKS NEW YORK

Copyright © 1997 by The Estate of Carl Sagan All rights reserved under International and Pan-American Copyright Conventions. Published in the United States by The Ballantine Publishing Group, a division of Random House, Inc., New York, and simultaneously in Canada by RandomHouse of Canada Limited, Toronto. http://www.randomhouse.com Library of Congress Catalog Card Number: 98-96080 ISBN: 0-345-37918-7

TO MY SISTER, CARI, ONE IN SIX BILLION

Contents
List of Illustrations .....
PART I THE POWER AND BEAUTY OF QUANTIFICATION

1. Billions and Billions 2. The Persian Chessboard 3. Monday-Night Hunters 4. The Gaze of God and the Dripping Faucet 5. Four CosmicQuestions 6. So Many Suns, So Many Worlds
PART II WHAT ARE CONSERVATIVES CONSERVING?

7. The World That Came in the Mail 8. The Environment: Where Does Prudence Lie? x • Contents 9. Croesus and Cassandra 10. A Piece of the Sky Is Missing 11. Ambush: The Warming of the World 12. Escape from Ambush 13. Religion and Science: An Alliance
PART III WHERE HEARTS AND MINDS COLLIDE

14. The CommonEnemy 15. Abortion: Is It Possible to Be Both "Pro-Life" and "Pro-Choice"? (cowritten with Ann Druyan) 16. The Rules of the Game 17. Gettysburg and Now (cowritten with Ann Druyan) 18. The Twentieth Century 19. In the Valley of the Shadow Epilogue by Ann Druyan Acknowledgments References Index

List of Illustrations
Photograph of Carl Sagan with Johnny Carson on the Tonight show, May 30, 1980..... Counting big numbers—six sketches by Patrick McDonnell The Grand Vizier's reward—three sketches by Patrick McDonnell Exponential growth in bacterial population, showing the flattening of the curve Exponential growth in human population, showing the flattening of the curve Ripples in water on the surface of a lake, showing the wave pattern 40 The electromagnetic wave spectrum—note the smallportion that we experience as visible light Surface-reflectance properties of ordinary pigments in visible light . .52 Carbon dioxide concentrations in Earth's atmosphere over time . .127 Timeline of global temperatures Greenhouse Warming—sketch by Patrick McDonnell Nuclear Power—sketch by Patrick McDonnell xii • List of Illustrations Solar Energy—sketch by Patrick McDonnell Human fetaldevelopment—drawings showing fetus at conception and at three weeks Human fetal development—drawings showing fetus at five weeks and at sixteen weeks Human fetal development—drawings showing resemblance of a human fetus to, in succession, a worm, an amphibian, a reptile, and a primate

Part I

THE POWER AND BEAUTY OF QUANTIFICATION

There are some . . . who think that the number of [grains of] sand isinfinite. . . . There are some who, without regarding it as infinite, yet think no number has been named which is great enough. . . . But I will try to show you [numbers that] exceed not only the number of the mass of sand equal to the Earth filled up ... but also that of a mass equal in magnitude to the Universe.
ARCHIMEDES (CA. 28y-2I2 B.C.),

The Sand-Reckoner

I never said it. Honest. Oh, Isaid there are maybe 100 billion galaxies and 10 billion trillion stars. It's hard to talk about the Cosmos without using big numbers. I said "billion" many times on the Cosmos television series, which was seen by a great many people. But I never said "billions and billions." For one thing, it's too imprecise. How many billions are "billions and billions"? A few billion? Twenty billion? A hundredbillion? "Billions and billions" is pretty vague. When we reconfigured and updated the series, I checked—and sure enough, I never said it. But Johnny Carson—on whose Tonight Show I'd appeared almost thirty times over the years—said it. He'd dress up in a corduroy jacket, a turtleneck sweater, and something like a mop for a wig. He had created a rough imitation of me, a kind of Doppelganger,...