Kitabı oku: «Symphony in C»

Contents

COVER

TITLE PAGE

COPYRIGHT

DEDICATION

PROLOGUE

SILENCE

MOVEMENT I—EARTH: Carbon, the Element of Crystals

Prelude—Before Earth

Exposition—Earth Emerges and Evolves

Development—Deep Earth Carbon

Recapitulation—Carbon Worlds

Coda—Unanswered Questions

MOVEMENT II—AIR: Carbon, the Element of Cycles

Introduction—Before Air

Arioso—The Origin of Earth’s Atmosphere

Intermezzo—The Deep Carbon Cycle

Arioso, da Capo—Atmospheric Change

Coda—The Known, the Unknown, and the Unknowable

MOVEMENT III—FIRE: Carbon, the Element of Stuff

Introduction—Material World

Scherzo—Useful Stuff

Trio—Nano Stuff

Scherzo, da Capo—Stories

Coda—Music

MOVEMENT IV—WATER: Carbon, the Element of Life

Introduction—The Primeval Earth

Exposition—Origins of Life

Development—Life Evolving (Theme and Variations)

Recapitulation—The Human Carbon Cycle

Finale—Earth, Air, Fire, and Water

PICTURE SECTION

NOTES

INDEX

ACKNOWLEDGMENTS

ABOUT THE AUTHOR

ABOUT THE BOOK

ALSO BY ROBER T M. HAZEN

ABOUT THE PUBLISHER

Prologue

LOOK AROUND YOU. Carbon is everywhere: in the paper of this book, the ink on its pages, and the glue that binds it; in the soles and leather of your shoes, the synthetic fibers and colorful dyes of your clothes, and the Teflon zippers and Velcro strips that fasten them; in every bite of food you eat, in beer and booze, in fizzy water and sparkling wine; in the carpets on your floors, the paint on your walls, and the tiles on your ceilings; in fuels from natural gas to gasoline to candle wax; in sturdy wood and polished marble; in every adhesive and every lubricant; in the lead of pencils and the diamond of rings; in aspirin and nicotine, codeine and caffeine, and every other drug you’ve ever taken; in every plastic, from grocery bags to bicycle helmets, cheap furniture to designer sunglasses. From your first baby clothes to your silk-lined coffin, carbon atoms surround you.

Carbon is the giver of life: Your skin and hair, blood and bone, muscle and sinews all depend on carbon. Every cell in your body—indeed, every part of every cell—relies on a sturdy backbone of carbon. The carbon of a mother’s milk becomes the carbon of her child’s beating heart. Carbon is the chemical essence of your lover’s eyes, hands, lips, and brain. When you breathe, you exhale carbon; when you kiss, carbon atoms embrace.

It would be easier for you to list everything you touch that lacks carbon—aluminum cans in your fridge, silicon microchips in your iPhone, gold fillings in your teeth, other oddities—than to enumerate even 10 percent of the carbon-bearing objects in your life. We live on a carbon planet and we are carbon life.

Every chemical element is special, but some elements are more special than others. Of all the periodic table’s richly varied denizens, the sixth element is unique in its impact on our lives. Carbon is not simply the static element of “stuff.” Carbon provides the most critical chemical link across the vastness of space and time—the key to understanding cosmic evolution. Over the course of almost 14 billion years, the Universe has evolved and become ever more richly patterned, with seemingly endless fascinating and quirky behaviors. Carbon lies at the heart of this evolution—choreographing the emergence of planets, life, and us. And, more than any other ingredient, carbon has facilitated the rapid emergence of new technologies, from steam engines of the Industrial Revolution to our modern “Plastic Age,” even as it accelerates unprecedented changes in environment and climate on a planetary scale.

Why focus on carbon? Hydrogen is a far more abundant chemical element, helium more stable, and oxygen more reactive. Iron, sulfur, phosphorus, sodium, calcium, nitrogen—all have fascinating stories to tell. All played critical roles in Earth’s complex evolution. But if you wish to find meaning and purpose in the vast cold and dark of the Universe, look to carbon; carbon, by itself and in chemical combinations with other atoms, provides unmatched cosmic novelty and unparalleled potential for cosmic evolution.

Of more than 100 chemical elements, carbon stands out as an element of our aspirations and fears. Novel carbon-based materials, invented by the thousands every year—Kleenex, spandex, Freon, nylon, polyethylene, Vaseline, Listerine, Bactine, Scotch tape, Silly Putty—enhance our lives in countless ways, both seen and unseen. But the proliferation of these synthetic chemicals has led to unintended consequences: troubling holes in the protective ozone layer, deadly allergic reactions, and carcinogens by the score. As the basis of all biomolecules, no other element contributes so centrally to the well-being and sustainability of life on Earth, including our human species. But carbon atoms, when missing or misaligned, can lead to disease and death.

The near-surface carbon cycle stabilizes Earth’s climate, ensures the health of ecosystems, and provides us with our most abundant supplies of inexpensive energy. Yet, if the distribution of carbon atoms becomes skewed by natural or human activities—erupting volcanoes, burning coal, an errant asteroid, vanishing forests—climates can change and ecosystems can collapse. And carbon’s influence is not confined to the near-surface realm of the living; carbon’s behavior in Earth’s hidden, deep interior epitomizes the dynamic processes that set apart our planet from all other known worlds.

The story of carbon is, in a sense, the story of everything. Yet mysteries about this ubiquitous, indispensable element abound. We don’t know how much carbon Earth holds, nor do we fully comprehend its varied forms hidden deep within our planet. We don’t understand the movements of carbon atoms as they cycle between Earth’s surface and its deep interior, nor can we say whether those movements have changed significantly through billions of years of Earth history—through “deep time.” Despite the existence of millions of known carbon compounds, scientists have only just begun to explore the richness of carbon chemistry. And the greatest mystery of all—the origin of life—is inextricably linked to the behavior of carbon in complex chemical combinations with other elements.

From quantities and forms, to movements and origins, what we know about carbon is dwarfed by our ignorance. We must find answers, but how can we hope to bridge such yawning chasms in our understanding? The very structure of the scientific enterprise would seem to conspire against sustained progress. Universities lack departments of carbon science, and large-scale, cross-disciplinary research ventures are rare. Scientific discovery rests on asking questions about the natural world, but it also depends on finding resources in a climate of limited time and money, at a time when disciplinary specialization often trumps integration.

Who will champion a different kind of research support?

The scene is the venerable Century Association club in New York City, early 2007, where the fund-raisers with the Carnegie Institution for Science have invited several dozen potential donors to an elegant dinner. The economy is booming, and Barack Obama is still a senator from Illinois. Paintings and sculptures by some of the greatest artists in American history line the spacious, wood-paneled rooms of the club. The major artworks, by such luminaries as John Frederick Kensett, Winslow Homer, and Paul Manship, were proffered in exchange for coveted and pricey club memberships. It was a great deal all around: the Century Association built a superb collection of masterpieces, while the artists gained access to wealthy patrons who could afford the club’s steep initiation fees.

I was the after-dinner speaker, and my theme was origins-of-life research, an intrinsically entertaining topic that was enhanced by simple props: a glass of carbonated soda water, a rock picked up in a nearby park, a teaspoon, and a straw. Presto!—a user-friendly demonstration of the chemical steps by which life might have emerged from a deep, hot, carbon-rich volcanic environment on the ocean floor. That my ideas were a bit controversial—a source of a lively, sometimes acrimonious debate with skeptical peers—added a bit of spice to my remarks. As a bonus, everyone was given a copy of Genesis, my recent book on the subject. I remember feeling a kinship with the artists whose work hung about me. Like them, I was singing for my supper, trying to catch the eye of some prospective patron, hoping for that next commission that would allow my colleagues and me to create a new scientific canvas.

Science isn’t cheap. It can cost $100,000 per year to support each graduate student or postdoc. New analytical machines can run upwards of a million dollars, with service contracts and replacement parts adding 10 percent or more per year to the price tag. Travel to conferences, page charges for publications, and basic lab supplies like test tubes, reagents, and Kimwipes are essential. And don’t get me started on “overhead.” Without support from industry, government agencies, and private foundations, scientific research would quickly wither and die. But it’s a tough road writing grant proposals to agencies and foundations, requesting $100,000 per year with less than a 10 percent chance of winning funding.

So there I was in the Big Apple, hat in hand, promoting science to a room full of nonscientists. One might do a score of such events without a nibble, but you have to try. The evening was fun, but soon forgotten in the crush of research projects and grant deadlines. And then came the phone call that changed everything.

It was three months later, early spring 2007, as Washington was coming into bloom.

“Hi Bob. Jesse Ausubel here, from the Sloan Foundation in New York.” Apparently I’d met Jesse at the Century Association talk, but I didn’t remember him. He seemed cordial but businesslike, his voice a pleasant baritone.

“The Sloan Foundation is considering new programs.” My ears perked. Sloan supports major science research and education efforts: an ambitious Census of Marine Life, the digital sky survey that discovered dark energy, NPR, and PBS.

“We’re wondering whether you’d be interested in discussing a program on the deep origins of life?” The subject of my New York talk, the very speculative hypothesis that life emerged from a deep volcanic zone on the ocean floor, had evidently hit the mark.

Ausubel told me that Sloan’s programs typically run for ten years at $7 to $10 million per year, paused, and waited for some kind of reaction. From me, silence. A one with eight zeros paralyzed my brain.

Eventually, I recovered and we began to discuss details. I suggested that focusing exclusively on deep origins of life was too narrow a view for a big ten-year effort. A host of fundamental mysteries relate to carbon at the planetary scale—not just in biology, but also in physics, chemistry, and geology. I explained that we can’t really understand life’s ancient, mysterious origins until we understand the broader story of carbon in Earth.

Jesse Ausubel liked the idea of a comprehensive approach: physics, chemistry, geology, and biology; 4.5 billion years of Earth history; crust to core, at scales from nano to global. He offered a one-year, $400,000 exploratory grant—“preapproved,” he said—to gather experts from around the world, hold workshops, define what we know and what we don’t know, and consider a global strategy to transform our understanding of Earth’s carbon.

This was no mere canvas. It was an insanely ambitious Beethoven symphony with unprecedented forces—a great bellowing chorus, multiple operatic soloists, and an oversized orchestra with myriad voices from tuba to piccolo. Nothing like it had ever been attempted before.

Fast-forward a year, to May 15, 2008. More than 100 experts gathered from around the world.1 Distinguished senior professors joined early career scientists from a dozen countries and as many scientific disciplines. We were tasked with discovering whether the rationale and will existed to tackle carbon science in a new, integrated approach.

Day 1 wasn’t all that encouraging, as scientists seldom stray far from their comfort zones. In spite of lofty rhetoric about “abandoning silos” and “crossing boundaries,” the biologists pretty much talked to biologists, while geophysicists and organic chemists also huddled within their specialized subgroups.

Day 2 was better. Gradually, as a succession of vivid talks provided glimpses of unexplored vistas—the puzzle of carbon in Earth’s core, the enigmatic ancient origins of life, the stately cycling of plate tectonics, hints of a vast subsurface microbial biosphere—we saw our narrow specialties in new, broader contexts. For the first time, we learned about paradoxical, unexplored connections between exploding volcanoes and diamond deposits, plate tectonics and climate change, and chemically reactive minerals and hidden deep life. The fascination of carbon science as a universal integrating theme seduced us.

By the end of Day 3, the structure for a new global endeavor had been framed. Leaders emerged and enthusiasm was high. Observers from the Sloan Foundation felt the energy in the room and saw the commitment in our eyes; they quickly gave a green light for the Deep Carbon Observatory.2 Ours would be a global endeavor of unusual scientific ambition and scope. The prospect was thrilling, but I suspect that every participant also worried about being part of a spectacular, embarrassing, expensive failure.

A decade later, the adventure has exceeded our most ambitious vision. An international army of carbon researchers—more than a thousand scientists from fifty countries—tackles the mysteries of carbon in Earth. With total international funding approaching a half-billion dollars from dozens of agencies and foundations worldwide, the Deep Carbon Observatory represents one of the most comprehensive and broadly interdisciplinary scientific endeavors in history.

As with any successful science program, we have learned a lot, but we’ve also become more keenly aware of how much we don’t know. Nagging, unanswered questions have become more deeply etched, more insistent drivers of future research. The paradox of science is that the more we know, the more we realize is unknown, perhaps even unknowable. Each discovery opens a door to a vaster unexplored landscape.

I’m driven to share some of the emerging, breathtaking vistas of carbon science—to chronicle the discoveries made, as well as the great unknown that remains to be explored. But how? If I were John Frederick Kensett or Winslow Homer, perhaps I could paint a picture. Words are harder. A multivolume encyclopedia of carbon could scarcely do justice to the many nuances of the subject. How, then, can carbon’s story be captured within the pages of a single book? The opportunity beckoned, but I was stymied. The blank page mocked me until Jesse Ausubel suggested a path forward.

“You must write a symphony!” he commanded.3

Jesse knew I had spent forty years as a symphony musician, juggling long days of lab work and evening gigs as a trumpeter with many groups—a regular with the Washington Chamber Symphony and National Gallery Orchestra, an extra with the National Symphony Orchestra and Washington National Opera. I had played every symphony of Beethoven, Brahms, Schuman, and Mendelssohn many times over. Still, at first his remark was puzzling. A symphony in words, not music? Four movements of . . . what?

I was uncertain and confused, but the metaphor also made sense on several levels. Like the varied physicists, chemists, biologists, and geologists of the Deep Carbon Observatory, a symphony orchestra features diverse specialists, each with years of training and dedication. Each orchestra musician has a distinctive instrument; violin and tuba, flute and snare drum, trumpet and viola—every timbre and range is essential, but none alone can unleash the swelling grandeur of the whole. So it is with the symphony of carbon science. Without the many voices of the Deep Carbon Observatory, the Symphony in C could never be heard.

The metaphor also recognizes that beautiful solos periodically emerge from the orchestra’s fabric. Our carbon symphony thus features the exceptional contributions of individual women and men of science, even as it integrates their focused research into a larger work with grander themes.

Like every symphony, this volume is a personal journey—idiosyncratic in content, limited in scope, composed from my own biased perspective, and playing out in many moods. I have benefited from the work of hundreds of colleagues, but this telling of the carbon story is inherently personal. Many other symphonies in C are waiting to be written.

As the parallels between the scientific endeavor and great orchestral compositions came into focus, I warmed to the idea of Symphony in C, though I struggled to envision a coherent framework. Then a thought: Ancient scholars postulated the existence of four elements—Earth, Air, Fire, and Water—each “essence” with a distinctive set of characteristics, each an irreducible component of the Universe, but collectively the source of all material creation. Carbon, alone among the atoms of the periodic table, displays the varied characteristics of all four classical elements, which suggest a four-movement framework for our story.

As in a symphony, the book’s four movements differ in their broad themes, their moods, and their tempi. “Movement I—Earth” examines minerals and rocks, the solid crystalline foundation of our planet. The movement begins with the dawn of creation, long before the formation of planet Earth, when atoms of carbon were forged from smaller atomic bits. It shifts to the emergence and evolution of Earth’s mineral wealth—a celebration of the growing diversity and exuberant beauty of crystalline carbon compounds.

The focus of “Movement II—Air” is Earth’s stately carbon cycle. Carbon atoms constantly shift among reservoirs, trading places between the oceans and atmosphere, plunging into the deep interior by way of plate tectonics and venting back to the surface in the hot gases released from hundreds of active volcanoes. For millions of years, this deep carbon cycle has enjoyed a reliable balance—an equilibrium that human actions may now be altering in ways that will lead to unintended consequences. Like the slow movement of a symphony, this topic calls for a softer, gentler treatment.

Carbon’s dynamic roles in energy, industry, and emerging high-tech applications demand the punchy, fast-paced Scherzo of “Movement III—Fire.” Carbon is the element of “stuff”—essential materials with myriad properties that benefit every facet of our lives. Stories of scientists and musicians punctuate the Scherzo, as carbon permeates every aspect of our lives.

And finally, “Movement IV—Water” explores the origins and evolution of life. The movement opens peacefully as life emerges from Earth’s primitive ocean, but it relentlessly accelerates with life’s astonishing evolutionary diversifications and innovations. Symphony in C rushes to a unifying Finale in which the many themes of carbon science come together.

Settle into your seats. The lights are dimming. Our story begins at the beginning, before carbon, even before time, as the Universe is about to emerge from absolute nothingness.