Billions & Billions

by Carl Sagan

  From paper clips, rubber bands, hair dryers, ballpoint pens, computers, dictating and copying machines, electric mixers, microwave ovens, vacuum cleaners, dish and clothes washers and driers, widespread interior and street lights, to automobiles, aviation, machine tools, hydroelectric power plants, assembly line manufacturing, and enormous construction equipment, the technology of our century has eliminated drudgery, created more leisure time, and enhanced the lives of many. It has also upended many of the routines and conventions that were prevalent in 1901.

  The use of potentially life-saving technology differs from nation to nation. The United States, for example, has the highest infant mortality of any industrial nation. It has more young black men in prison than in college, and a greater percentage of its citizens in jail than any other industrial nation. Its students routinely perform poorly on standardized science and mathematics tests when compared with students of the same age in other countries. The disparity in real income between the rich and the poor and the decline of the middle class have been growing swiftly over the last decade and a half. The United States is last among industrialized nations in the fraction of the national income given each year to help people in other countries. High technology industry has been fleeing American shores. After leading the world in almost all these respects in midcentury, there are some signs of decline in the United States at century’s end. The quality of leadership can be pointed to, but so can the dwindling penchant for critical thinking and political action in its citizens.

  TOTALITARIAN AND MILITARY

  TECHNOLOGY

  The means of making war, of mass killings, of the annihilations of whole peoples, has reached unprecedented levels in the twentieth century. In 1901, there were no military aircraft or missiles, and the most powerful artillery could loft a shell a few miles and kill a handful of people. By the second third of the twentieth century, some 70,000 nuclear weapons had been accumulated. Many of them were fitted to strategic rocket boosters, fired from silos or submarines, able to reach virtually any part of the world, and each warhead powerful enough to destroy a large city. Today we are in the throes of major arms reductions, both in warheads and delivery systems, by the United States and the former Soviet Union, but we will be able to annihilate the global civilization into the foreseeable future. In addition, horrendously deadly chemical and biological weapons are in many hands worldwide. In a century bubbling over with fanaticism, ideological certainty, and mad leaders, this accumulation of unprecedentedly lethal weapons does not bode well for the human future. Over 150 million human beings have been killed in warfare and by the direct orders of national leaders in the twentieth century.

  Our technology has become so powerful that not only on purpose but inadvertently we have become able to alter the environment on a large scale, and threaten many species on Earth, our own included. The simple fact is that we are performing unprecedented experiments on the global environment and in general hoping against hope that the problems will solve themselves and go away. The one bright spot is the Montreal Protocol and ancillary international agreements by which the industrial nations of the world agreed to phase out production of CFCs and other chemicals that attack the ozone layer. But in reducing carbon dioxide emissions to the atmosphere, in solving the problem of chemical and radioactive wastes, and in other areas progress has been slow to dismal.

  Ethnocentric and xenophobic vendettas have been rife on every continent. Systematic attempts to annihilate whole ethnic groups have occurred—most notably in Nazi Germany, but also in Rwanda, the former Yugoslavia, and elsewhere. Similar tendencies have existed throughout human history, but only in the twentieth century has technology made killing on such a scale practical. Strategic bombing, missiles, and long-range artillery have the “advantage” that the combatants need not come face-to-face with the agony they have worked. Their consciences need not trouble them. The global military budget at the end of the twentieth century is close to a trillion dollars a year. Think of how much human good could be purchased for even a fraction of that sum.

  The twentieth century has been marked by the collapse of monarchies and empires and the rise of at least nominal democracies—as well as many ideological and military dictatorships. The Nazis had a list of reviled groups they set out to systematically exterminate: Jews, gays and lesbians, socialists and communists, the handicapped, and people of African origin (of whom there were almost none in Germany). In the militantly “pro-life” Nazi regime, women were relegated to “Kinder, Küche, Kircher”—children, cooking, the church.* How affronted a good Nazi would be at an American society that, more than any other country, dominates the planet, in which Jews, homosexuals, the handicapped, and people of African origin have full legal rights, socialists are at least tolerated in principle, and women are entering the workplace in record numbers. But only around 11 percent of the members of the U.S. House of Representatives are women, instead of a little more than 50 percent, as it would be if proportional representation were practiced. (The corresponding number for Japan is 2 percent.)

  Thomas Jefferson taught that a democracy was impractical unless the people were educated. No matter how stringent the protections of the people might be in constitutions or common law, there would always be a temptation, Jefferson thought, for the powerful, the wealthy, and the unscrupulous to undermine the ideal of government run by and for ordinary citizens. The antidote is vigorous support for the expression of unpopular views, widespread literacy, substantive debate, a common familiarity with critical thinking, and skepticism of pronouncements of those in authority—which are all also central to the scientific method.

  THE REVELATIONS OF SCIENCE

  Every branch of science has made stunning advances in the twentieth century. The very foundations of physics have been revolutionized by the special and general theories of relativity, and by quantum mechanics. It was in this century that the nature of atoms—with protons and neutrons in a central nucleus and electrons in a surrounding cloud—was first understood, when the constituent components of protons and neutrons, the quarks, were first glimpsed, and when a host of exotic short-lived elementary particles first showed up under the ministrations of high energy accelerators and cosmic rays. Fission and fusion have made possible the corresponding nuclear weapons, fission power plants (a not-unmixed blessing), and the prospect of fusion power plants. An understanding of radioactive decay has given us definitive knowledge of the age of the Earth (about 4.6 billion years) and of the time of the origin of life on our planet (roughly 4 billion years ago).

  In geophysics, plate tectonics was discovered—a set of conveyer belts under the Earth’s surface carrying continents from birth to death, and moving at a rate of about an inch a year. Plate tectonics is essential for understanding the nature and history of landforms and the topography of the sea bottoms. A new field of planetary geology has emerged in which the landforms and interior of the Earth can be compared with those of other planets and their moons, and the chemistry of rocks on other worlds—determined either remotely or from returned samples brought back by spacecraft or from meteorites now recognized as arising from other worlds—can be compared with the rocks on Earth. Seismology has plumbed the structure of the deep interior of the Earth and discovered beneath the crust a semi-liquid mantle, a liquid iron core, and a solid inner core—all of which must be explained if we wish to know the processes by which our planet came to be. Some mass extinctions of life in the past are now understood by immense mantle plumes gushing up through the surface and generating lava seas where solid land once stood. Others are due to the impact of large comets or near-Earth asteroids igniting the skies and changing the climate. In the next century, at the very least we ought to be inventorying comets and asteroids to see if any of them has our name on it.

  One cause for scientific celebration in the twentieth century is the discovery of the nature and function of DNA, deoxyribonucleic acid—the key molecule responsible for heredity in humans and in most other plants
and animals. We have learned to read the genetic code and in increasing numbers of organisms we have mapped all the genes and know what functions of the organisms most of them are in charge of. Geneticists are well on their way to mapping the human genome—an accomplishment with enormous potential for both good and evil. The most significant aspect of the DNA story is that the fundamental processes of life now seem fully understandable in terms of physics and chemistry. No life force, no spirit, no soul seems to be involved. Likewise in neurophysiology: Tentatively, the mind seems to be the expression of the hundred trillion neural connections in the brain, plus a few simple chemicals.

  Molecular biology now permits us to compare any two species, gene by gene, molecular building block by molecular building block, to uncover the degree of relatedness. These experiments have shown conclusively the deep similarity of all beings on Earth and have confirmed the general relations previously found by evolutionary biology. For example, humans and chimpanzees share 99.6 percent of their active genes, confirming that chimps are our closest relatives, and that we share with them a recent common ancestor.

  In the twentieth century for the first time field researchers have lived with other primates, carefully observing their behavior in their natural habitats, and discovering compassion, foresight, ethics, hunting, guerrilla warfare, politics, tool use, tool manufacture, music, rudimentary nationalism, and a host of other characteristics previously thought to be uniquely human. The debate on chimpanzee language abilities is still ongoing. But there is a bonobo (a “pigmy chimp”) in Atlanta named Kanzi who easily uses a symbolic language of several hundred characters and who has also taught himself to manufacture stone tools.

  Many of the most striking recent advances in chemistry are connected with biology, but let me mention one that is of much broader significance: the nature of the chemical bond has been understood, the forces in quantum physics that determine which atoms like to link up with which other atoms, how strongly, and in what configuration. It has also been found that radiation applied to not implausible primitive atmospheres for the Earth and other planets generate amino acids and other key building blocks of life. Nucleic acids and other molecules in the test tube have been found to reproduce themselves and reproduce their mutations. Thus substantial progress has been made in the twentieth century toward understanding and generating the origin of life. Much of biology is reducible to chemistry and much of chemistry is reducible to physics. This is not yet completely true, but the fact that it is even a little bit true is a most important insight into the nature of the Universe.

  Physics and chemistry, coupled with the most powerful computers on Earth, have tried to understand the climate and general circulation of the Earth’s atmosphere through time. This powerful tool is used to evaluate the future consequences of the continued emission of CO2 and other greenhouse gases into the Earth’s atmosphere. Meanwhile, much easier, meteorological satellites permit weather prediction at least days in advance, avoiding billions of dollars in crop failures every year.

  At the beginning of the twentieth century astronomers were stuck at the bottom of an ocean of turbulent air and left to peer at distant worlds. By the end of the twentieth century great telescopes are in Earth orbit peering at the heavens in gamma rays, X rays, ultraviolet light, visible light, infrared light, and radio waves.

  Marconi’s first radio broadcast across the Atlantic Ocean occurred in 1901. We have now used radio to communicate with four spacecraft beyond the outermost known planet of our Solar System, and to hear the natural radio emission from quasars 8 and 10 billion light-years away—as well as the so-called black body background radiation, the radio remnants of the Big Bang, the vast explosion that began the current incarnation of the Universe.

  Exploratory spacecraft have been launched to study 70 worlds and to land on three of them. The century has seen the almost mythic accomplishment of sending 12 humans to the Moon and bringing them, and over a hundred kilograms of moon rocks, back safely. Robotic craft have confirmed that Venus, driven by a massive greenhouse effect, has a surface temperature of almost 900° Fahrenheit; that 4 billion years ago Mars had an Earth-like climate; that organic molecules are falling from the sky of Saturn’s moon Titan like manna from Heaven; that comets are made of perhaps a quarter of organic matter.

  Four of our spacecraft are on their way to the stars. Other planets have recently been found around other stars. Our Sun is revealed to be in the remote outskirts of a vast, lens-shaped galaxy comprising some 400 billion other suns. At the beginning of the century it was thought that the Milky Way was the only galaxy. We now recognize that there are a hundred billion others, all fleeing one from another as if they are the remnants of an enormous explosion, the Big Bang. Exotic denizens of the cosmic zoo have been discovered that were not even dreamt of at the turn of the century—pulsars, quasars, black holes. Within observational reach may be the answers to some of the deepest questions humans have ever asked—on the origin, nature, and fate of the entire Universe.

  Perhaps the most wrenching by-product of the scientific revolution has been to render untenable many of our most cherished and most comforting beliefs. The tidy anthropocentric proscenium of our ancestors has been replaced by a cold, immense, indifferent Universe in which humans are relegated to obscurity. But I see the emergence in our consciousness of a Universe of a magnificence, and an intricate, elegant order far beyond anything our ancestors imagined. And if much about the Universe can be understood in terms of a few simple laws of Nature, those wishing to believe in God can certainly ascribe those beautiful laws to a Reason underpinning all of Nature. My own view is that it is far better to understand the Universe as it really is than to pretend to a Universe as we might wish it to be.

  Whether we will acquire the understanding and wisdom necessary to come to grips with the scientific revelations of the twentieth century will be the most profound challenge of the twenty-first.

  * After outlining traditional Christian views of women from patristic times to the Reformation, the Australian philosopher John Passmore (Man’s Responsibility for Nature: Ecological Problems and Western Traditions [New York: Scribner’s, 1974]) concludes that Kinder, Kuche, Kircher “as a description of the role of women is not an invention of Hitler’s, but a typical Christian slogan.”

  CHAPTER 19

  IN THE VALLEY

  OF THE SHADOW

  Is this, then, true or mere vain fantasy?

  EURIPIDES,

  Ion (ca. 410 B. C.)

  Six times now have I looked Death in the face. And six times Death has averted his gaze and let me pass. Eventually, of course, Death will claim me—as he does each of us. It’s only a question of when. And how.

  I’ve learned much from our confrontations—especially about the beauty and sweet poignancy of life, about the preciousness of friends and family, and about the transforming power of love. In fact, almost dying is such a positive, character-building experience that I’d recommend it to everybody—except, of course, for the irreducible and essential element of risk.

  I would love to believe that when I die I will live again, that some thinking, feeling, remembering part of me will continue. But as much as I want to believe that, and despite the ancient and worldwide cultural traditions that assert an afterlife, I know of nothing to suggest that it is more than wishful thinking.

  I want to grow really old with my wife, Annie, whom I dearly love. I want to see my younger children grow up and to play a role in their character and intellectual development. I want to meet still unconceived grandchildren. There are scientific problems whose outcomes I long to witness—such as the exploration of many of the worlds in our Solar System and the search for life elsewhere. I want to learn how major trends in human history, both hopeful and worrisome, work themselves out: the dangers and promise of our technology, say; the emancipation of women; the growing political, economic, and technological ascendancy of China; interstellar flight.

  If there were life after death,
I might, no matter when I die, satisfy most of these deep curiosities and longings. But if death is nothing more than an endless dreamless sleep, this is a forlorn hope. Maybe this perspective has given me a little extra motivation to stay alive.

  The world is so exquisite, with so much love and moral depth, that there is no reason to deceive ourselves with pretty stories for which there’s little good evidence. Far better, it seems to me, in our vulnerability, is to look Death in the eye and to be grateful every day for the brief but magnificent opportunity that life provides.

  For years, near my shaving mirror—so I see it every morning—I have kept a framed postcard. On the back is a penciled message to a Mr. James Day in Swansea Valley, Wales. It reads:

  Dear Friend,

  Just a line to show that I am alive & kicking and going grand. It’s a treat.

  Yours,

  WJR

  It’s signed with the almost-indecipherable initials of one William John Rogers. On the front is a color photo of a sleek, four-funneled steamer captioned “White Star Liner Titanic.” The postmark was imprinted the day before the great ship went down, losing more than 1,500 lives, including Mr. Rogers’s. Annie and I display the postcard for a reason. We know that “going grand” can be the most temporary and illusory state. So it was with us.

  We were in apparent good health, our children thriving. We were writing books, embarking on ambitious new television and motion picture projects, lecturing, and I continued to be engaged in the most exciting scientific research.

  Standing by the framed postcard one morning late in 1994, Annie noticed an ugly black-and-blue mark on my arm that had been there for many weeks. “Why hasn’t it gone away?” she asked. So at her insistence I somewhat reluctantly (black-and-blue marks can’t be serious, can they?) went to the doctor to have some routine blood tests.