Mark Fiege

the atomic scientists, the SENSE OF WONDER, AND THE BOMB

ABSTRACT

The atomic scientists' intense fascination with nature helped them to produce the knowledge necessary to create the bomb. These physicists, chemists, and mathematicians believed that nature should be reduced to its essential parts, observed, explained in terms of laws, and manipulated for human purposes. Their relationship to nature, however, included more than just this instrumental mentality and method, which alone were insufficient to yield scientific insights. Walking, hiking, and mountain climbing loosened the scientists' minds and helped them to think about atoms and subatomic particles. More important, the scientists' deep feelings about nature—curiosity and emotions generally known as wonder—inspired them to undertake the research that eventually informed their Manhattan Project work. By describing a little-known side of the bomb, this essay advances a recent scholarly trend toward studies of the hidden or unexpected environmental features of America's atomic project.

IN DAY OF TRINITY, a history of the atomic bomb, the journalist Lansing Lamont recounted a story about Robert Oppenheimer, the scientific director of the Manhattan Project and the guiding light of Los Alamos, the federal government's secret laboratory located in the high country of north central New Mexico. On July 15, 1945, Oppenheimer and other project personnel gathered at Trinity Site, some 150 miles south of their research compound, to test the weapon that they had conceived and built. As the final hours in the countdown slipped away, Oppenheimer climbed the one-hundred-foot steel tower that loomed above ground zero. Like the other Manhattan Project scientists, he was anxious about the test, and he wanted to reassure himself that the bomb was set to go. Finding nothing amiss, he descended and returned to base camp, several miles away, and there struck up a conversation with the metallurgist Cyril Smith. In the midst of their talk, Lamont reported, Oppenheimer paused and gazed at the sheer slope of the darkening Sierra Oscura, immediately east of the test site. "Funny," he mused, "how the mountains always inspire our work."¹

Lamont never explained what Oppenheimer meant by that comment. It was one quotation extracted from numerous interviews with Manhattan Project participants, and the journalist clearly intended it to add little but geographical texture to a fast-paced story centered on colorful personalities, technological wizardry, secret strategizing, espionage, the demands of global war, and a climactic, mind-boggling explosion. The mountains that spoke to Oppenheimer provided the backdrop to the drama, but that was all. Peaks, slopes, rock, and the sunlight and shadow that played across them—these were part of the story's setting, not its substance.

Environmental historians, however, might well pause and reflect on Oppenheimer's statement before hastening to the mushroom cloud. Mountains, we know, are not trivial, and the powerful feelings that they evoke are worthy of attention. Modern people have gone to the mountains for all kinds of reasons: to escape the constraints of everyday life, experience physical challenge, gain an altered sense of self, witness beauty, feel awe and wonder, and come close to God. Mostly, modern people have viewed the mountains as sources of insight and joy: Physical elevation has involved a corresponding elevation of the soul.² In light of this popular attitude, Oppenheimer's comment might seem strange. How could mountains matter to scientists focused on mastering nature for terrible purposes? How could a source of spiritual insight and goodness contribute to the creation of such a fearsome, destructive, perhaps immoral, weapon?

That strangeness intensifies when Oppenheimer is juxtaposed to the figures most often associated with the mountains' majesty. John Muir, Stephen Mather, Ansel Adams, David Brower, Olaus and Margaret Murie, Howard Zahniser, and like-minded artists, writers, naturalists, and preservationists exemplified a deep appreciation of, and attachment to, the high country. These nature lovers, moreover, were the kind of people who often opposed the bomb and doubted the science that informed it. Consider Zahniser, whose tireless political work resulted in the Wilderness Act, one of America's greatest achievements in nature preservation. News of the bomb in August 1945 literally nauseated him. "The splitting of the atom," his biographer has explained, "violated an ethical code to which [he] subscribed, a code that obligated mankind to understand nature before manipulating it."³ In the context of people such as Zahniser and the postwar preservationist reaction against the bomb, Oppenheimer's statement might seem dubious. How could he claim to be moved by mountains when he was so unlike the people whom we know the mountains moved? Indeed, how could he truly understand nature at all?

The apparent inconsistency between building the bomb and finding inspiration in the mountains might lead us to dismiss or ignore Oppenheimer's comment, or, like Lamont, downplay it. We might conclude that the physicist was a hypocrite, a tragic protagonist in a Faustian bargain, or a Frankenstein deluded by dreams of omnipotence. We might think that whatever his utterance meant, it has become irrelevant in light of the terror that he and his colleagues unleashed upon the world. Thus we might be tempted to pass over his words as we hurry toward the mushroom cloud and the toxic history that it has come to symbolize.

Such a choice would be a mistake, however, because it would preclude an opportunity to gain a deeper understanding of America's troubled atomic past. By uncovering the origins and implications of Oppenheimer's comment, I propose to offer a brief history of the bomb that challenges simple assumptions about atomic scientists, mountains, and mushroom clouds.⁴ Oppenheimer (1904–1967) and Zahniser (1906–1964) were, after all, contemporaries, and despite their differences, they had much in common. Both valued knowledge, and both found solace in books and ideas. Both had strong feelings about things eternal, infinite, and divine. Both were patriots who supported the United States in its wars against Germany and Japan. And both, it turns out, found inspiration in nature. Mountains and other natural environments stimulated the likes of Oppenheimer no less than people such as Zahniser; from alpine vistas and other landscape vantages, the atomic scientists gained insight into the universe and its possibilities.

Understanding this alternative history of the bomb requires us to examine the multifarious ways that the atomic scientists understood nature and interacted with it. In part, the scientists' mentality was reductive, abstract, and mechanistic; the universe consisted of matter, forces, motion, and voids that could be, and should be, broken into parts (sometimes literally so), observed, explained in terms of laws, and manipulated for human purposes. Formulating abstract hypotheses and then testing these with mathematical calculations and laboratory experiments, they discovered, between the 1890s and the late 1930s, X rays and radiation, the atomic nucleus and the electrons that surrounded it, the equivalence of mass and energy, the relativity of time and motion, the uncertainty of velocity and position, the neutron and other subatomic particles, previously unknown elements and their properties, and nuclear fission. In the process, the atomic scientists developed new, powerful tools and laboratory techniques, such as the Geiger counter, the cloud chamber, the mass spectrometer, the particle accelerator, and the use of neutrons to penetrate the nucleus. The atomic scientists' instrumental method was as useful at it was insightful. Certainly the knowledge and technologies that it yielded enabled them to produce the death machine that the United States dropped on Japan.⁵

The production of scientific knowledge and techniques, however, involved more than just heartless men in white coats calculating on chalkboards and experimenting in laboratories. The atomic scientists' formal papers, in which they represented nature with abstract mathematical equations, masked the subjective intuitions, sense perceptions, kinesthetic movements, aesthetic judgments, and emotional reactions that profoundly shaped their research. Behind the cold logic of numbers existed a domain of thought and action crucially important to atomic science yet unacknowledged in its formal discourse. Oppenheimer's comment about mountains gestured toward this domain, and if we follow his gaze and the sweep of his hand, we can begin to see it more clearly. For many atomic scientists, interaction with mountains and other relatively undeveloped landscapes, especially by means of walking, hiking, and climbing, enabled their intellectual processes and helped them to imagine the microscopic nature that they could not see, but that they knew existed.

The physicist Werner Heisenberg (1901–1976), for example, well knew the subjective domain where intuition in combination with the experience of landscape yielded insights into nature's deepest recesses. On a summer day in 1922, Heisenberg joined the Danish physicist Niels Bohr (1885–1962) for a long walk on the Hainberg, a forested prominence outside Göttingen, Germany. Such excursions were a common practice among atomic scientists. Away from stuffy classrooms and urban noise, relaxed by rhythmic movement and emotionally uplifted by expansive vistas, they clarified their ideas. As Bohr and Heisenberg traversed the heights, the older scientist held forth on atomic theory. Somewhere along the way, Heisenberg began to grasp a central feature of Bohr's method: The imagination of physical phenomena, and the intuitive understanding of the relationship between theory and phenomena, preceded mathematical explanation. As Heisenberg stated, "knowledge of nature was obtained primarily in this way, and only as the next step can one succeed in fixing one's knowledge in mathematical form and subjecting it to completely rational analysis."⁶ It was an important lesson. As we will see, Heisenberg's intuition in conjunction with his movement across landscape later yielded one of his greatest atomic discoveries.

There existed still other, even more important parts of the subjective domain that influenced the atomic scientists' work. Linked to their formal method were their motivations. The atomic scientists investigated nature for various reasons, among them professional ambition and prestige.⁷ But of all the reasons for studying the atom, the psychological condition of wonder may have been the strongest. Physicists, chemists, and mathematicians studied atoms out of profound curiosity, and when they detected the inner workings of the tiny particles, they experienced awe, amazement, delight, and transcendence. Their feelings were closely associated with their responses to other natural things, such as mountains, sunsets, planets, galaxies, and the universe itself. Physical science opened infinite vistas on a range of phenomena, from the fantastically small to the incomprehensibly large; the scientists' realization of the vastness, unity, mystery, and sublimity of the cosmos evoked feelings of wonder that drove them onward. Among those so impelled was Albert Einstein (1879–1955), whose famous mass-energy equation, E=mc2, proved enormously useful to the scientists who created the bomb. Yet building a weapon was not Einstein's purpose. Rather, he attributed the scientific quest to a state of mind that he called the "cosmic religious feeling," an intuitive awareness of the universe's size, grandeur, order, and rationality. "I maintain," he stated in 1930, "that the cosmic religious feeling is the strongest and noblest motive for scientific research."⁸

Despite the importance of wonder to the atomic scientists, they seldom discussed it, especially in the context of their formal method. Their reticence was rooted in history. In the sixteenth and seventeenth centuries, wonder had an accepted place in European science. Natural philosophers believed that it prompted their curiosity and inspired the disciplined, methodical investigation of physical phenomena. The Enlightenment emphasis on objectivity, however, relegated wonder to the margins of the scientific enterprise. Instrumental measurement, mathematical description, and the goal of eliminating all human bias—including emotion—made it formally irrelevant, if not illegitimate. By the twentieth century, a reader could search in vain for references to it in scientific papers, including those authored by Oppenheimer and his cohorts.⁹

Yet wonder did not disappear. That it could be difficult to find in the atomic scientists' mathematical calculations did not mean that it was absent from their lives or that it had no influence on their work. From a young age, they marveled at nature's myriad forms. In particular, elements, forces, motion, light, and numerical patterns attracted and inspired them. When their study of these physical phenomena unsettled their understanding of the universe, their awestruck reactions confirmed that the feeling was far from dead.¹⁰

Figure 1. Albert Einstein, c. 1930, in the Desert at Palm Springs, California

Library of Congress. Photograph by William H. Smith, courtesy AIP Emilio Segrè Visual Archives.
The physicist Freeman Dyson once remarked that "the chief reward for being a scientist is not the power and the money but the chance of catching a fleeting glimpse of the transcendent beauty of nature."

The atomic scientists' experience of wonder in part derived from the very nature of their subject. Atomic particles were so small and strange, so unlike anything in the everyday world, that they defied complete comprehension. Even the most brilliant scientists at moments expressed astonishment at the intangible, uncertain realm in which the familiar laws of gravity, mass, and motion did not apply; some even believed that language itself could not capture the atom's essential weirdness. To the extent that the atomic scientists were able to describe and interpret their bizarre subject, they had to exercise a faculty more often associated with artists than with people such as themselves—the imagination. Indeed, the deeper the scientists probed, the greater the need to conjure unexpected, fantastical, wondrous things: electrons that shimmered around the nucleus; light that consisted of both distinct particles and a continuous wave; a peculiar force that in binding the atom absorbed a portion of its mass. But no matter how much they revealed of the atom, Einstein, Oppenheimer, and their colleagues could not explain all of it. That which defied their powers, that which remained unfathomable and mysterious, forever ignited their wonder.¹¹ Although wonder had no place in their formal writings, the atomic scientists could not suppress it. In personal conversations, interviews, and popular writings, they voiced it.¹²

The atomic scientists' experience of wonder matched that of other prominent contemporary observers of nature, including the biologist, writer, and preservationist Rachel Carson (1907–1964). In 1956, Carson authored an article in Woman's Home Companion titled "Help Your Child to Wonder." From an early age, Carson asserted, children are drawn to butterflies, birds, forests, seashores, and other parts of nature. "A child's world is fresh and new and beautiful, full of wonder and excitement," she wrote. Although most people by adulthood lost "that clear-eyed vision, that true instinct for what is beautiful and awe-inspiring," some did not. Carson pointed to the Swedish oceanographer Otto Pettersson (1848–1941) as an example, and she urged parents to cultivate in their offspring a "sense of wonder."¹³ It might seem odd to place the atomic scientists in such company, to compare rather than contrast Oppenheimer, the father of the bomb, with Carson, the mother of modern environmentalism. Yet in their capacity for wonder and in their fundamental enthusiasm for nature, the two were very similar.¹⁴

Oppenheimer's comment about mountains thus opens a potentially unsettling insight: A passion for nature motivated the atomic scientists to accumulate the knowledge and techniques that eventually allowed them to build the bomb. The scientific method, narrowly defined, was the instrument by which they explored, manipulated, and explained nature; that combination of curiosity and emotion generally called wonder prompted them to do the work.¹⁵ Between the 1890s and the 1940s, across mountain ranges and other landscapes from Germany to California, they pieced together a picture of the universe the magnitude and mystery of which left them in awe. Wonder, of course, did not compel them to transform their knowledge into a weapon. Yet the feeling certainly was integral to the discoveries without which the weapon would have been impossible.

Examining the relationship between the atomic scientists' enthusiasm for nature and the bomb advances a recent trend in atomic historiography. Scholarship on the bomb and its legacy is deep, and includes accounts of the Manhattan Project, biographies of scientists and politicians, analyses of politics, diplomacy, and military doctrines, studies of atomic cities, test sites, uranium mines, and power plants, and discussions of cultural and political reactions to America's atomic complex.¹⁶ A few scholars, however, also have begun to examine hidden or unexpected environmental features of the nation's atomic history. Often their work draws connections among seemingly disparate landscapes, processes, and perspectives, focusing on, for example, the similarities between atomic reserves and nature parks, the links between atomic and ecological science, and the aesthetic of the sublime as applied to mushroom clouds.¹⁷ Such studies counter the popular and scholarly tendency to overlook the ways that the nation's atomic project, especially the bomb, was deeply embedded in the human relationship to nature. Clearly, the bomb shaped, and was shaped by, society's efforts to know, manipulate, and appreciate the natural world. Moreover, as I argue here, reverence for nature—awe and delight in natural things—was a precondition to the bomb's production.

Of the hundreds of atomic scientists whose research and discoveries established the body of knowledge essential to the Manhattan Project and the bomb, this essay focuses on some of the most able, influential, and prominent. The story follows them through the life course, examining their childhoods, upbringings, educations, careers, and experiences at Los Alamos. Nature was present in their lives in multiple ways; understanding the bomb that they created requires us to take seriously Oppenheimer's observation, to think about wonder experienced in relation to both mountains and microscopic particles.

PETER PANS OF THE HUMAN RACE

LIKE OTTO PETTERSON, the oceanographer whose childlike capacity for wonder drew Rachel Carson's admiration, many atomic scientists never lost the wide-eyed curiosity that characterized their youthful embrace of the world. Albert Einstein believed that his interest in space and time was typical of a child, not an adult. Leo Szilard (1898–1964), a Hungarian physicist who worked on the Manhattan Project and opposed the indiscriminate use and proliferation of atomic weapons, thought of himself similarly. "As far as I can see," he wrote near the end of his life, "I was born a scientist. I believe that many children are born with an inquisitive mind, the mind of a scientist, and I assume that I became a scientist because in some ways I remained a child." Niels Bohr, the Dane who helped found quantum mechanics and who came to Los Alamos with the British mission to the Manhattan Project, had the same childlike qualities. "To be able to fully understand Bohr's rare nature," recalled a childhood friend, "one must be clear that through the years he has retained the boy in him, retained the boy's love of play and the boy's curiosity, the latter of course being a very important thing for a researcher in science." And in the view of Isidor Rabi (1898–1988), who served as an adviser to Robert Oppenheimer and the other Los Alamos scientists, "physicists are the Peter Pans of the human race. They never grow up, and they keep their curiosity."¹⁸

The paths of inquiry and inspiration that carried the atomic scientists to the bomb sometimes began with specific forms of nature. A native New Yorker, Robert Oppenheimer became interested in the structure of crystals while building an impressive mineral collection. His childhood curiosity led him to chemistry, then physics. Growing up in Vienna during the 1880s, Lise Meitner (1878–1968) wondered about the spectrum of color produced by a drop of oil on a puddle of water. The questions that she asked eventually resulted in a doctorate in physics, and she became one of the discoverers of atomic fission, the basic process that made possible the bomb. In some cases, a dramatic event sparked a lifelong fascination. When he was a boy, Isidor Rabi looked down a New York street one evening and saw the rising moon staring down at him. "And it scared the hell out of me! Absolutely scared the hell out of me," he recalled of that profound moment, and its magic ultimately impelled him into science. The experiences of children such as Oppenheimer, Meitner, and Rabi mirrored events in Rachel Carson's girlhood. According to one story, Carson's discovery of a fossilized shell and her questions about the origin and the fate of the animal that had inhabited it marked the beginning of her enduring interest in the ocean.¹⁹

Most youngsters who became atomic scientists did not exhibit a single-minded interest in natural phenomena, however. A few may have felt no attraction at all. Rudolf Peierls (1907–1995), coauthor of a report on the bomb's feasibility (the Frisch-Peierls Memorandum) and a member of the British mission, manifested a boyhood fascination for machinery, railways, automobiles, and radio. Similarly, Robert Serber (1909–1997), a protégé of Oppenheimer and author of The Los Alamos Primer, a summary of atomic bomb knowledge, showed a decidedly practical bent while growing up in Philadelphia, and he eventually earned an engineering degree.²⁰ In contrast to Peierls and Serber, many, perhaps most, proto-atomic scientists were interested in both nature and technology. Niels Bohr grew up absorbed in the natural history lessons taught by his biologist father and by various teachers and tutors, yet he was also interested in clocks and he became an accomplished bicycle mechanic. Railroads fascinated the young Victor Weisskopf (1908–2002), but as he matured, he focused his attention on astronomy. Eventually he earned a doctorate in physics and became the deputy leader of the Manhattan Project's Theoretical Division. Perhaps the interest in both technology and nature came together most completely in the person of Enrico Fermi (1901–1954), an Italian who oversaw the world's first controlled chain reaction and who worked on the bomb at Los Alamos. According to Fermi's biographers, he and a boyhood friend "tried to explain a certain number of natural phenomena, and for a long time they were puzzled by what seemed to them the deepest mystery of nature," the behavior of a spinning top. After much intense reading, observation, analysis, and debate, the boys "arrived at a working theory of the gyroscope."²¹

For some atomic scientists, a fascination with technology masked deep feelings about nature. During his Wyoming boyhood, Robert Wilson (1914–2000) often rode after cattle, and he also enjoyed the practical tinkering, repairing, and fabricating that took place in the ranch blacksmith shop. He became absorbed in amateur radio, and he and a friend built an early version of a hang glider, which they flew over the prairie. Wilson's interests eventually carried him into physics and a PhD from the University of California, Berkeley, where he conducted research on the cyclotron, the first particle accelerator. From his academic work, Wilson went to Los Alamos and the bomb. Yet this practitioner of cowboy physics also was a romantic who later claimed that as a youth he had "a very strong feeling about nature." American Indians and mountain men drew his admiration, as did a wise uncle who seemed to know everything about horses, weather, and wildflowers. The Wyoming landscape, too, sparked his sense of wonder: "A sunset, or looking at a mountain ... I remember being strongly affected by that and wanting to know more about it. A kind of a reverence for nature, and a desire to identify with it." Wilson believed that such feelings were a hidden part of the cowboy tradition, "a 'sissy' part," he said, "which doesn't normally ... show through."²²

Wilson evidently developed his interests and fashioned his sensibilities on his own initiative, from personal experiences, his uncle's example, and stories told by cowboys around the campfire. Other budding atomic scientists, however, received more structured, systematic, concerted guidance. Field trips, hiking, and other outdoor experiences, often in the company of teachers, tutors, or parents, stimulated their curiosity. These guided activities showed the influence of the nature study movement that became popular during the late nineteenth and early twentieth centuries. Educational reformers believed that the artificiality of modern life dulled children's sensibilities and stunted their physical, moral, and spiritual development. As an antidote, the reformers advocated science lessons, field trips, plant study, rock and mineral collection, weather observation, and other activities which, they claimed, would liberate children's creativity, teach them lessons in right living, and give them an appreciation for the wonder of God's creation.²³

Nature study influenced many, and probably most, atomic scientists. In addition to outings with his father, Niels Bohr ventured into the Danish landscape in the company of his siblings and an aunt, Hanna Adler, a prominent educational innovator. "When she could spare time from her school work," Bohr said of Adler, "she took us on Sundays around Copenhagen's natural history and ethnological exhibitions and art museums[,] and in the summer holidays at Naerumgaard where she accompanied us often on foot or on a bicycle in the woods and fields of the district we learned both about nature and human life, while she jokingly or seriously talked to us about everything that could catch our imagination." Emilio Segrè (1905–1989), who later directed the research on the detonation of the atomic bomb, benefited from a private tutor, "Signorina Maggini," who "had just graduated from a teachers' training college." Maggini took the young boy on long excursions on foot into the hills around Tivoli, the Italian city that the Segrè family called home. "During those walks," Segrè stated, Maggini taught him "history, natural history, poetry, civics, and so on," and he recalled that he "greatly enjoyed learning things such as the physiology of digestion, illustrated by the experiment of chewing on a piece of bread until it became sweet through the action of the enzyme ptyalin on starch." Robert Oppenheimer attended Felix Adler's Ethical Culture School in Manhattan, which encouraged hands-on experience. There he studied with a science teacher, Augustus Klock, who occasionally took him on "a mineral hunting junket" as a reward for his accomplishments in the chemistry laboratory.²⁴

Nature study also shaped the outlook of thousands of children besides those who became atomic scientists. One of those young naturalists was Rachel Carson. In keeping with the movement's methods and objectives, Carson's mother exposed her daughter to the landscape around their Pennsylvania home, and she encouraged Carson's interest in books about nature.²⁵ The seed planted in the child bore fruit in the scientist and writer; Carson's celebration of the sense of wonder was her effort to spread her mother's precious gift.

The formative experiences of at least one atomic Peter Pan resembled those of Carson. Nature study and the guidance of a devoted parent shaped the physicist Richard Feynman (1918–1988) no less powerfully than they did the future author of "Help Your Child to Wonder" and Silent Spring. Feynman's father, Melville, was a salesman with frustrated scientific aspirations who carefully nurtured his son's interest in natural phenomena. According to Feynman's biographer, when the two took walks near their home in Far Rockaway, New York, the father "would turn over stones and tell [his son] about the ants and the worms or the stars and the waves." Melville encouraged Richard to mistrust formal knowledge and received wisdom, and to ask questions and describe in his own words what he observed. This approach to nature became the core of Richard's own method as he matured into a scientist and proponent of educational techniques that enabled children to discover for themselves how the world functioned.²⁶

Nature study with loving parents, wonder experienced in local landscapes, scientific careers, the championing of unmediated contact between children and the physical world: Carson and Feynman shared much. Yet their common origins and development ultimately propelled them on different paths. Whereas Carson's childhood fascinations launched her in the direction of tide pools, oceans, and environmental advocacy, Feynman's steered him toward atoms, electrons, and the bomb.

WE TOUCHED THE NERVE OF THE UNIVERSE

AS THE ATOMIC SCIENTISTS entered their teenage years, their childhood interests and experiences began to take adult form. Outdoor play and excursions into the countryside grew into enthusiasm for walking, hiking, skiing, horseback riding, and mountain climbing; interests in minerals, stars, or spinning tops evolved into a passion for formal scientific inquiry. Often recreation and research were directly connected. In August 1923, when he was fifteen, Victor Weisskopf and a friend, George Winter, climbed the Loser, a mountain in the Austrian Alps. As darkness fell, the boys "sat back to back, ... eyes focused on the heavens," waiting for the annual Perseid meteor shower. When streaks of red, yellow, and white lit up the sky, Weisskopf and Winter recorded their observations in notebooks. At daybreak, the exhausted but elated friends descended the mountain, the raw data for a scientific paper in their knapsacks. They submitted their findings to the newsletter of the Friends of the Stars, an organization of amateur astronomers, but the editors, recognizing the sophistication of the boys' scientific accomplishment, forwarded the manuscript to a scholarly journal, which published it. Weisskopf exulted in "the joy of insight," and he and Winter proudly associated their mountaineering skills with their enthusiasm for scientific investigation. The boys disdained soccer and other team athletics as the unintellectual pursuits of "sport guys," and they convinced themselves that their preferred recreational activities, hiking and skiing, were not really sports. "They involved something higher," Weisskopf asserted: "the love of nature."²⁷

The same interests and enthusiasms characteristic of the atomic scientists' childhoods and teenage years continued to develop and flourish as they underwent graduate training and entered their careers. They embraced parks, the countryside, and wilderness landscapes, and many interspersed their scientific work with outdoor pursuits. Such activities were characteristic of well educated, relatively affluent, leisured Europeans and Americans. Yet even those scientists from modest or working-class origins, or from rural cultures centered on outdoor labor, also enjoyed nature and found beauty in it.²⁸

Robert Oppenheimer reveled in the outdoor life. He especially liked grueling horseback rides in the deserts and mountains of New Mexico, which he first visited in 1922. The experience of those remote, rugged landscapes, often in harsh weather, stirred his emotions. "It was evening when we came to the river/with a low moon over the desert/that we had lost in the mountains, forgotten,/what with the cold and the sweating/and the ranges barring the sky," he wrote in "Crossing," published in 1928.²⁹ He briefly contemplated an undergraduate major in mining engineering, less because he wanted to rip apart mountains than because he imagined himself traveling through them in pursuit of the crystals that intrigued him. He was a romantic, and the mystique of the rough-and-ready, itinerant mining engineer evidently appealed to him. "I loved that kind of life," he recalled. In the end, though, he chose another major. "Study chemistry," a friend advised him; "there are always summer vacations."³⁰

Many atomic scientists devoted their summer vacations and other free time to mountain hikes. Around 1910, Max Teller began to take his young son, Edward, on trips to the mountains near Budapest, and these excursions fostered in the boy a love of mountains. When Edward (1908–2003) reached adulthood and embarked on a career in physics, he courted Augusta Harkanyi-Schütz on hikes in the Tatra Mountains, the massif of the central Carpathian range. During a visit to the Buda Mountains near the Hungarian capital, Edward—to the accompaniment of honking geese—proposed marriage; Augusta (d. 2000), better known by her nickname, Mici, accepted. When the Tellers immigrated to the United States in the 1930s, they struck up a friendship with a German émigré couple, the physicist Hans Bethe (1906–2005) and his wife Rose Ewald Bethe (c.1918- ), and the two couples often enjoyed hiking together. In 1937, they took an extended trip through some of the major ranges of the American West, stopping at national parks and monuments such as Rocky Mountain, Grand Teton, Mount Rainier, and Crater Lake. According to Hans, Edward "always used to say, 'This is almost as beautiful as the High Tatra.'" Like the Tellers and other scientific couples, Hans and Rose Bethe discussed weighty matters during high country rambles. In the summer of 1942, while hiking in Yosemite National Park, the Bethes pondered whether Hans should participate further in the Manhattan Project. They decided that he should, and he went on to serve as the head of the Theoretical Division at Los Alamos.³¹

Figure 2. Robert Oppenheimer with His Horse, Crisis, at his New Mexico Mountain Ranch

Photo by Mrs. J. Robert Oppenheimer, courtesy AIP Emilio Segrè Visual Archives.
Oppenheimer relished grueling horseback rides across undeveloped terrain, one of which he memorialized in the poem "Crossing."

Mountaineering appealed to the most adventuresome atomic scientists. During his San Francisco boyhood, Luis Alvarez (1911–1988) was primarily interested in machinery, electronics, and radio. Yet he also enjoyed Boy Scout camping, and when he was 12, he spent "three wonderful weeks" with his father on a Sierra Club High Trip, hiking the John Muir Trail in the Sierra Nevada Mountains. When Alvarez finished high school, his father took him and his brother on a Sierra Club High Trip to British Columbia, where the young men scaled a glacier, learned rock-climbing techniques, and ascended Mount Resplendent. After the High Trip, Alvarez proceeded to college and the study of physics.³² Later, he joined other atomic scientists at Los Alamos and helped to develop the mechanism that detonated the bomb.

Alvarez's experiences with mountains and physics were hardly exceptional. Emilio Segrè became a lover of wildflowers, wild plant foods, and mountains. During the 1920s and 1930s, he sometimes teamed up with the physicist, entomologist, botanist, and paleontologist Franco Rasetti (1901–2001) for climbs in the Alps. A staunchly independent scientist who refused to work on the Manhattan Project, Rasetti took pride in scaling the Matterhorn and other peaks on difficult routes without the help of guides. Enrico Fermi sometimes joined Segrè and Rasetti; photographs from Segrè's camera show Fermi, Rasetti, and another physicist, Nello Carrara (1900–1993) on rocky peaks with their climbing rope and boots. The sense of wonder never left the scientists on such expeditions. On one climb, Segrè, Rasetti, and some companions found themselves in an electrical storm. "The sight of the sparks coming out of our ice axes and of our hair standing on end was truly spectacular, and scary," Segrè recalled.³³

A few physicists were able to afford rural or wilderness retreats from which they launched hikes, climbs, horseback rides, and other forays. During the 1920s and 1930s, Niels Bohr often took his family to Lynghuset (Heather House), their summer home at Tisvilde, a dispersed rural community about thirty miles north of Copenhagen. Through forests of birch, spruce, and pine, across moorland of heather, and along the seashore, Bohr took long walks with family, friends, and other scientists. An American equivalent to Bohr's Heather House was Perro Caliente, the rustic log cabin and small ranch in New Mexico's Sangre de Cristo Mountains that Robert Oppenheimer shared with his brother, Frank (1912–1985), a fellow physicist and Manhattan Project participant. Robert first viewed the place in 1928 while on a horseback ride; his reaction when told that it was for rent ("hot dog!") became the basis of its Spanish name. Perched in a meadow at an altitude of some 9,500 feet, Perro Caliente offered a stunning view of the pine-covered mountains and the Pecos Valley. The Oppenheimer brothers often went there during the summer, and it served as their base for horseback rides and hikes into the surrounding wilderness. Although most scientists did not own rural retreats, the practice was far from rare. In July 1953, for example, Rachel Carson moved into Silverledges, her summer cottage on the Maine coast.³⁴

Contact with parks, rural areas, and undeveloped landscapes was important to the atomic scientists, but for most, such places did more than just help them to relax and enjoy beauty. The experience of mountains and other environments inspired them, focused their minds, and helped them to understand matter, forces, energy, and light. Niels Bohr believed the environment of Tisvilde stimulated his intellectual creativity. He "felt ... that here he received inspiration," wrote his biographer, that "here his mind was in tune with nature." Robert Oppenheimer's relationship to Perro Caliente seems to have been more complicated. On one hand, he apparently wanted the place to be a retreat from academic pressures at the University of California, Berkeley, where he was a professor; discussion of physics generally "was forbidden at the ranch," recalled Robert Serber, Oppenheimer's student and close friend. On the other hand, Perro Caliente's beauty and tranquility activated Oppenheimer's mind and allowed it to range widely; the physicist could not help but think about atomic nature while he was in the mountains. The desire to institutionalize the interplay of unencumbered science and the experience of landscape pulled at Oppenheimer. "My two great loves are physics and New Mexico," he once told a friend. "It's a pity they can't be combined."³⁵

Many atomic scientists liked to mull over their research problems while strolling on mountain paths, along beaches, down country lanes, or through parks. The steady, rhythmic movement away from human constructions relaxed their minds and helped them to clarify their thoughts. As much kinesthetic, artistic, and improvisational as cerebral, scientific, and analytical, the method joined the atomic scientists to a peripatetic tradition that stretched back to the classical Greek philosophers. Like their ancient forebears, the atomic scientists walked less to reach a geographical destination than to ponder and resolve intellectual problems.³⁶ Eugene Wigner (1902–1995), a German expatriate who developed an early theory of neutron chain reaction—the basis of the atomic bomb—and who worked on the Manhattan Project at the University of Chicago, offered this description: "Once outside, my mind immediately begins to move freely and instinctively over my subject. Ideas come rushing to mind, without being called. Soon enough, the best answer emerges from the jumble. I realize what I can do, what I should do, and what I must abandon."³⁷

From childhood onward, atomic scientists associated walking outdoors with thinking. A family vacation to the mountains may have stimulated Edward Teller's keen interest in numbers. At age five, while on a walk with his mother, Hans Bethe grasped the concept of zero. When he was fourteen, Enrico Fermi began taking long walks with a friend and future physicist, Enrico Persico (1900–1969), during which they discussed scientific problems.³⁸ Habits established in youth continued into adulthood. Fermi and Bohr were famous for walking and thinking in the company of colleagues. Bethe and Teller discussed many topics on their hiking trips to the mountains or seashore, but "physics, especially nuclear physics," was their mainstay. Robert Oppenheimer and Ernest Lawrence (1901–1958), colleagues at the University of California, talked about physics during long walks along San Francisco Bay.³⁹

These out-of-doors forays prompted important discoveries. One spring day in 1905, Albert Einstein went for a long walk with a friend on the outskirts of Bern, Switzerland, where Einstein worked as a government patent clerk. The physicist felt that he was on the verge of a great insight, and he wanted to talk over his idea with his companion, a mechanical engineer. Einstein did not come up with firm conclusions during the outing, but he awoke the following morning greatly excited. Over the next several weeks, he laid out his theory of relativity, including his explanation of the equivalence of mass and energy, a concept that would account for the violent transformation at the heart of an atomic explosion.⁴⁰

Years later, in 1927, Werner Heisenberg's path led him to a revelation of extraordinary significance. Well past midnight on a winter evening, Heisenberg left his attic room at Niels Bohr's research institute in Copenhagen and went for a walk in nearby Faelled Park. Past the beech trees, under the stars, in the darkness, the thought occurred to him that it was impossible to calculate independently both the position and velocity of an electron. To pinpoint its position was to lose track of its velocity; to determine its velocity was to lose sight of its position. The mechanical act of determining one rendered the other unknowable. The principle of uncertainty that Heisenberg began to formulate on his nocturnal ramble was a major innovation in atomic physics. The behavior of electrons and other subatomic particles was indefinite, he realized, and could be described best according to statistical probabilities. It was in terms of such probabilities that the atomic scientists one day began to calculate the neutron penetration of nuclei, the process that finally made possible the bomb.⁴¹

Two refugee scientists, Lise Meitner and Otto Frisch (1904–1979), made a crucial contribution to the science of fission in late 1938 while traversing a portion of the wintry Swedish countryside. Meitner, accustomed to outings of six to eight miles, walked briskly through the snowy forest on that December day; Frisch, her nephew as well as colleague, accompanied her on skis. After some distance, they stopped. While Meitner sat on a log, resting, they came up with a solution to the problem that had absorbed them. When laboratory scientists directed a neutron into the nucleus of a uranium atom, the neutron caused the nucleus to wobble like a liquid drop, grow narrow in the middle, and bulge on either end. Two new drops—two incipient nuclei, each the core of a new atom—began to develop, and their positive electrical charges repelled them further and further apart. Eventually, the so-called strong force within each proto-nucleus completed the separation by pulling each into its own distinct unit. Borrowing the biological term for cell division, Meitner and Frisch dubbed the process fission.⁴² After the Second World War, of course, the popular term for fission became "splitting the atom," which called to mind not organic reproduction, but mechanical destruction—an ax cleaving firewood, or a steel wedge, driven by a sledgehammer, cracking apart a boulder.

For a few atomic scientists, at least, activities such as walking, hiking, or climbing were more than kinesthetic exercises that loosened their minds and enabled them to think of fantastically small things. Some found correspondences between the terrain that they traversed and the minute phenomena that they studied. High on an Alpine peak on a July afternoon in 1927, Franco Rasetti collected beetle specimens from the genus Bythinus while lecturing Emilio Segrè on the motion of atoms. There seems to have been no connection between Rasetti's multiple nature enthusiasms, save that he pursued them at the same time. Mountains, insects, and atoms were dissimilar forms of nature at radically contrasting spatial scales; each was to be studied and appreciated differently. Superficially, Rasetti's method seems consistent with the modern scientific method, which tended to break nature into parts. A closer look, however, reveals another picture. Rasetti gloried in the freedom of unguided climbs; analogously, he took pride in his independent research into the most accessible, unrestricted of atomic forms. When asked why he had chosen to study cosmic rays, the atomic nuclei that stream from outer space into Earth's atmosphere, he replied: "Because [they] are free and everywhere." Such was Rasetti's libertarian credo, which influenced his love of mountains as well as his fascination with atoms.⁴³

Figure 3. Enrico Fermi, Nello Carrara, and Franco Rasetti (L-R) Climbing in the Alps

Photo courtesy AIP Emilio Segrè Visual Archives.
"The sight of the sparks coming out of our axes and of our hair standing on end was truly spectacular, and scary," recalled Segrè, who took this picture.

Niels Bohr tried to draw an explicit connection between the nature that he could observe directly and the minute atoms that he could only imagine. He was fascinated by "the wonders of instinct," as one physicist said, and specifically by the anadromous movement of eels and salmon. Could atomic theory, Bohr asked, help scientists to understand the genetics and behavior of such creatures? For much of his life, Bohr doubted that it could. His outlook reflected the influence of his father, Christian, a physiologist who took a mechanistic view of organisms, but who was also drawn to the concept of vitalism, which held that mechanistic theories alone could not explain the life force that pulsed through an animal's body. Bohr's beliefs led him to articulate his theory of complementarity, according to which there can be mutually exclusive but equally valid—and therefore complementary—ways of understanding nature. In his final years, however, developments in the field of molecular biology caused him to adjust his view, and he anticipated that the application of atomic knowledge to biological research would generate the same kind of excitement that had swept through physics decades before. "I think that the feeling of wonder which physics had thirty years ago has taken a new turn," he stated in 1962. "Life will always be a wonder, but what changes is the balance between the feeling of wonder and the courage to understand."⁴⁴

For Bohr and his colleagues, salmon, mountains, or sunsets were not the only forms of nature that inspired the sense of wonder. So did time, space, forces, energy, light, particles, and atoms, all of the things to which they had devoted lifetimes of research. Physical science and its subjects were beautiful, sublime, and enchanting; indeed, the deeper the physicists, chemists, and mathematicians went, the grander their view.

Their discoveries delighted and excited them. Einstein called the principle of relativity "the happiest thought of my life." Heisenberg felt alarm, excitement, and giddiness when he first worked out the complex mathematical calculations that eventually led him to the problem of uncertainty. Gazing at the equations, he sensed "a strangely beautiful interior" below "the surface of atomic phenomena." Particle and wave mechanics entranced Robert Oppenheimer. "I never found physics so beautiful," he said. He liked cosmic rays, and he imagined their fragmentation into various particles upon striking Earth's atmosphere. "This theory of cascades or multiplicative showers, shining bright in his mind's eye," wrote one of his biographers, "was a glimpse of austere beauty that brought him his happiest hours of 1936."⁴⁵ Lise Meitner and Otto Frisch reacted with astonishment to the experiment that demonstrated the fission of a uranium atom. It was "impossible," "amazing," and "fantastic," they first thought; there must be "some mistake." But as they calculated the quantities using Einstein's mass-energy equation, they realized that there could be no doubt. Weeks later, Meitner still felt the euphoria. She wrote to Otto Hahn (1879–1968), who had conducted the laboratory experiment: "I am still happy about the marvelousness of these findings." The results astonished and delighted the global physics community, including Niels Bohr. "Oh but this is wonderful!" he exclaimed. "This is just as it must be!"⁴⁶

Looking back on the twentieth century's great atomic discoveries, some scientists expressed feelings of exaltation. "We touched the nerve of the universe," said Victor Weisskopf. "It was a great revolution that allowed us to get at the root of the matter—why are leaves green, why are metals hard, why are the mountains so high and not higher?" Isidor Rabi went even further; probing atoms, he glimpsed the divine. Although a New Yorker and the product of a machine-driven, modern city, Rabi had grown up spellbound by the Old Testament and by folktales inherited from his family's ancestral shtetl, nestled in the foothills of the Carpathian Mountains. Rabi was a mechanist, to be sure, but ultimately nature was a vast mystical realm of enchanting supernatural forces. Physics, he concluded in middle age, was "infinite," and it had led him to perceive "the mystery of it: how very different it is from what you can see, and how profound nature is." When a graduate student brought a scientific finding to him, he would ask: "Does it bring you near to God?"⁴⁷

Such feelings were so intense for Oppenheimer that they may have constrained his scientific work. Ever the romantic, he loved the poetry of John Donne and read the Bhagavad Gita, the great Hindu epic, in the original Sanskrit. The emotions that churned inside him could not help but influence his view of the universe. "It was as if he were aiming at initiating his audience into Nature's divine mysteries," the physicist Abraham Pais (1918–2000) recalled of an Oppenheimer lecture. Isidor Rabi, ironically, believed that this reverence blinded him: "His interest in religion resulted in a feeling for the mystery of the universe that surrounded him almost like a fog. He saw physics clearly ... but at the border he tended to feel that there was much more to the mysterious than there actually was." One of the most brilliant thinkers of his time, Oppenheimer never made the kind of discoveries that earned others the Nobel Prize. The sense of wonder that drew him to atoms may have prevented him from scrutinizing them deeply enough to win the greatest of all scientific honors.⁴⁸

Although perhaps unusual in their depth and fervor, Oppenheimer's romantic impulses were typical of many atomic scientists' feelings. Wonder, not a drive to dominate nature, amass wealth, or build weapons, had carried them to their discoveries. Until 1939, they speculated that the atom contained fantastic quantities of energy, but most of them did not believe that humankind could learn to extract and use it. Quantum mechanics remained an esoteric branch of physics, its practitioners absorbed in "the urge and fascination of a search into the deepest secrets of nature," in the words of the New Zealander Ernest Rutherford (1871–1937).⁴⁹

They could not ignore the implications of fission, of course. Like many other scientists in early 1939, Oppenheimer reacted with astonishment to its discovery. "That's impossible," he said upon receiving the news. But he and other scientists soon realized its truth, and almost instantly they grasped its potential.⁵⁰ Besides yielding light, heat, and radioactive gamma rays, fission released additional neutrons that in turn struck other nuclei, setting off a chain reaction mass-to-energy conversion that could culminate, theoretically, in an explosion.

Had political and military circumstances been different, the destructive nature of fission might have remained in the realm of theory for years, if not indefinitely. But that is not what happened. War erupted in 1939, and it compelled the atomic scientists to move chain reaction violence from theory to practice. Werner Heisenberg, Otto Hahn, Hans Geiger (1882–1945), and a few others remained in Germany and founded its atomic bomb project. But most of the scientists despised the Nazis' illiberalism, anti-Semitism, and militarism, and they feared the consequences if Germany built the weapon first. Save for researchers such as Lise Meitner in Sweden and Franco Rasetti in Canada, both of whom chose to abstain from working on weapons, the majority of the atomic scientists offered their services and prestige to Britain and the United States. By 1942, the Manhattan Project was underway; in early 1943, Oppenheimer greeted his colleagues as they arrived at Los Alamos.⁵¹

It was a turning point of profound significance. Knowledge that had resulted from the "cosmic religious feeling," as Einstein called it, would be put to military purposes. In developing the destructive potential of neutron and nucleus, however, the atomic scientists did not—could not—turn off or abandon the affinity for nature that had been so important to their earlier work. To the contrary, wonder still rippled through them, even as they involved themselves in the most instrumental project of their lives.

GOD AND NATURE ARE SIMPLE

THE NATURAL SETTING of Los Alamos reflected their basic sentiments. Oppenheimer chose the site not simply for its isolation and security, but because of its beauty and because of his intellectual and emotional attachment to the New Mexico high country. Here, at last, he would bring together his two great loves. High on a mesa top, surrounded by pines and stunning views of the Jemez Mountains, the Rio Grande Valley, and the Sangre de Cristo range, he and his colleagues would combine physics and physical setting in the service of making a weapon that might defend liberal democracy against the fascist threat. Despite doubts about living at a remote location above seven thousand feet in elevation, the scientists and their families on the whole responded enthusiastically to their new environment.⁵² Mud, dust, water shortage, shoddy construction, and other nuisances sometimes detracted from the vistas, but the residents struggled to minimize the disturbances and keep the surroundings consistent with their expectations and values. Desiring some shade for their children, and no doubt acting on their past experience of mountains and mountain resorts, Mici Teller and a group of women staged a sit-in to prevent an Army Corps of Engineers bulldozer operator from knocking down pine trees.⁵³ Environmental amenities mattered to Mici and her friends and neighbors; some pine trees must remain standing.

As they labored on the bomb, the atomic scientists took in the spectacular scenery. On winter mornings, they watched the sun rise over the Sangre de Cristos to the east; on summer afternoons, they gazed at enormous thunderclouds that billowed above the peaks. "I never tired of that view," Robert Wilson wrote.⁵⁴ Emilio Segrè and the junior physicists in his charge perhaps had the best opportunity to merge daily labors with the Los Alamos environment. Whereas most of the scientists worked in the laboratories, offices, and meeting rooms of the Tech Area, a secure compound within the town, Segrè's team occupied a U.S. Forest Service log cabin in Pajarito Canyon, fourteen miles distant. Segrè and his scientists were investigating the spontaneous fission of uranium and plutonium, and the site shielded their experiments from background noise and electromagnetic disturbances. Seclusion brought a welcome side benefit. Each morning, the group climbed into a jeep and drove along a track lined with purple and yellow asters and Indian rock art, finally arriving at a grove in which sat the cabin. "Seldom have I seen such a romantic and picturesque place," Segrè observed.⁵⁵

Segrè and the other atomic scientists, however, did more than simply appreciate the view, the shade of the pines, and the wildflowers. They and their families also spent weekends and Sundays experiencing the open country that surrounded Los Alamos. Horseback riding, picnicking, fishing, and skiing were favorite pursuits, as were hiking and climbing. In some instances, the atomic scientists' instrumentalist proclivities shaped their outdoor recreations; while Mici Teller rescued pine trees for shade, other Los Alamos residents destroyed them in the name of sport. The chemist George Kistiakowsky (1900–1982), the Manhattan Project's explosives expert, felled trees with plastic explosive to make "a nice little ski slope," which went into operation in late 1944. Some 150 people joined the Sawyer's Hill Ski Tow Association, including such scientific luminaries as Enrico Fermi, Hans Bethe, Robert Bacher (1905–2004), and Niels Bohr. Mostly, however, the atomic scientists' embrace of mountains and canyons was unmediated by such intensive landscape modifications.⁵⁶

Figure 4. Niels Bohr Skiing at Los Alamos During the Manhattan Project

Photograph by John P. Miller, courtesy AIP Emilio Segrè Visual Archives, Segrè Collection.

Figure 5. A Mountain Hike

AIP Emilio Segrè Visual Archives, Fermi Film Collection.
Los Alamos scientists, left to right, Isador Rabi, Enrico Fermi, L. D. Percival King, during a hike in Frijoles Canyon, Bandelier National Monument, noted for its ancient American Indian ruins.

An especially popular retreat was Bandelier National Monument, which occupied a swath of canyons and mesas south of the laboratory reserve. The National Park Service had closed Bandelier to the general public for the duration of the war, but left it open to Los Alamos personnel. The monument's archaeological remains, canyons, watercourses, vegetation, and wildlife left the visitors with many vivid memories. In the fall of 1944, Laura Fermi (1907–1977), Enrico Fermi's wife, accompanied Niels Bohr on a hike into Frijoles Canyon, "where his mind could focus on the marvels of nature that surrounded us." Nearly sixty years old, Bohr took great delight in a skunk, his first encounter with the North American mammal. Jumping across a stream, "his body straightened" and "his eyes glowed with pleasure." When Fermi and Bohr arrived at the mouth of the canyon, they "stopped in silence" to gaze at the Rio Grande, the cacti, the canyon wall, the blue sky, and a puffy cloud. "There is a sense of reverence in the perception of some landscapes," Fermi wrote of that enchanted moment.⁵⁷

Such encounters with nature were not simply pastimes or diversions. For some Los Alamos personnel, contact with canyons, forests, lakes, and peaks was essential to their work, because it rejuvenated them after intense, exhausting weeks in laboratories and meeting rooms. "The ability to hike in the mountains on Sundays was one of the things that kept one sane," said the British metallurgist Cyril Smith (1903–1992), whose favorite hiking partner was Edward Teller. Emilio Segrè, the Swiss physicist Hans Staub (1908–1980), and the Briton James Chadwick (1891–1974), the discoverer of the neutron, found a similar reward in fishing. Segrè had learned to angle along the Merced River in Yosemite National Park, and at Los Alamos he continued the activity. Standing on the bank, enjoying the wildflowers or the autumn colors and observing the wildlife, his mind relaxed and he began to meditate.⁵⁸

Yet the atomic scientists' thoughts did not stray far from their work. Most important to their experience of nature at Los Alamos was the peripatetic intellectual tradition, the compulsive habit of walking, thinking, and talking. Niels Bohr and his son, Aage (1922- ), also a physicist, took a long walk each day during which they discussed scientific problems. "God and nature are simple," the elder Bohr told the chemist Joseph Hirschfelder (1911–1990) while they strolled; "it is we who are complicated!" The Swiss chemist and physicist Egon Bretscher (1896–1973), an enthusiastic mountaineer and perambulator, often departed Los Alamos for its environs. A guard at the main gate recorded his reason: "Walking!!!" After the physicist Herbert Anderson (1914–1988) arrived at Los Alamos in the autumn of 1944, he accompanied Enrico Fermi on a four-hour hike on some of the Italian's favorite trails. Along the way, Anderson absorbed a lecture on the research being conducted at Los Alamos. Theodore Welton (1918- ) received a similar lecture from Richard Feynman during a descent into a nearby canyon. When the chemist James Bryant Conant (1893–1978), the director of the federal government's Office of Scientific Research and Development, visited Los Alamos to advise Oppenheimer, the two scientists talked during hikes. And for some Manhattan Project personnel, the ascent of mountain peaks yielded deep insights. "Very often on a Sunday," Hirschfelder wrote, Hans Bethe "would climb to the top of Lake Peak" in the Sangre de Cristos "with Enrico Fermi and some of his other friends and sit there in the sunshine discussing physics problems. This is how many discoveries were made."⁵⁹

The scientists' observation of nature, not just movement through it, stimulated their imaginations and helped them with their work. Pondering the potential physical effects of the bomb, a group of researchers decided to take a lesson from natural history, and they traveled into the desert near Flagstaff, Arizona, to examine Meteor Crater, an enormous hole left over from an ancient impact. On other occasions, the matter and energy that swirled around them stimulated their minds and supplied analogies for understanding microscopic particles. This was especially so for Richard Feynman, whose brilliant intellect and experiential method—learned in childhood from his father—enabled him to make important contributions to the research at Los Alamos. "It is all really like the shape of clouds," Feynman remarked to the Polish mathematician Stanislaw Ulam (1909–1984) as they observed puffs of white glide across the blue sky. "As one watches them they don't seem to change, but if you look back a minute later, it is all very different."⁶⁰

At Los Alamos, Oppenheimer and his colleagues never closed their hearts and minds to atomic wonder. It was true that they had devoted themselves to a profoundly instrumental project. Poring over diagrams, manipulating metals, fabricating and assembling components, they were like engineers. Yet they did more than just build a machine. Researching the properties of chemical compounds, the spontaneous fission of plutonium, or the shock waves that imploded the bomb's core into a critical mass, they opened new vistas on the universe. "We all agreed that the work we were engaged in was fascinating," recalled Victor Weisskopf. "Never before had my colleagues and I lived through a period of so much learning, of so many insights into the structure of matter in all its manifestations."⁶¹

Their research, however, did not necessarily bring delight and exaltation. The atomic scientists' awareness of the bomb's terrible power opened them to another form of wonder, a dark mixture of awe and fear called dread. A dreadful thought first occurred to them in 1942, during a meeting at the University of California at Berkeley. As Edward Teller calculated on the chalkboard, Oppenheimer and other physicists realized that the intense heat of fission might set off nuclear reactions culminating in the ignition of atmospheric nitrogen. Shaken, Oppenheimer suspended the seminar and telephoned Arthur Holly Compton (1892–1962), then in charge of the nascent bomb project. They had "found something very disturbing—dangerously disturbing," Oppenheimer reported. After further analysis, the scientists realized that they had miscalculated the potential for such a catastrophe.⁶² But for the remainder of the Manhattan Project, a number of them could not completely quell the fear that the weapon they were creating might engulf the world in flames. Reason dictated that it could not happen; imagination and emotion said otherwise.

Anxieties mounted as the Manhattan Project neared its climax. The Allied forces' gradual defeat of Germany and their impending victory over Japan led some scientists to question the need for the bomb. They and a number of their colleagues also began to feel the awful moral burden of their impending complicity in the mass annihilation of human life. During a policy meeting in May 1945, Oppenheimer still could speak of "the visual effect of an atomic bombing," which "would be tremendous. It would be accompanied by a brilliant luminescence which would rise to a height of 20,000 to 30,000 feet." But in moments of introspection, he and others worried about the people whom such a wondrous spectacle would destroy. Overwork, excitement, and apprehension imposed intense psychological strain on the Los Alamos scientists. Early one morning, they and their families gathered outside their homes and stared at a strange bright object in the sky. Awe and fear swept through them. And then one scientist, an astronomer, reassured them that it was only Venus.⁶³

The name of the test site reflected the atomic scientists' cosmic and eschatological vision. To some, Trinity probably called to mind the Father, Son, and Holy Ghost of Christian belief. To the deeply intellectual and spiritual Oppenheimer, reader of Sanskrit and the Bhagavad Gita, it may have evoked the Hindu trinity of Brahma, Vishnu, and Shiva. For Hindus as for physicists, matter and energy are never ultimately destroyed; they are only transformed. What Brahma creates, Vishnu preserves, and Shiva reduces to primordial nature; and what Shiva thus destroys, Brahma refashions, and Vishnu again sustains, an endless cycle of transfigurations that is the fundamental dynamic of the universe.⁶⁴

As the moment of truth approached, the atomic scientists were not entirely confident in their instrumental abilities, nor were they even completely certain that they wanted the test to turn out as planned. "Human calculation indicates that the experiment must succeed," said Hans Bethe, the chief theoretician, in a speech to his colleagues before they boarded the buses to Trinity. "But will nature act in conformity with our calculations?" Feelings of doubt gnawed at them as they rolled down the highway. "I think most of the people on those school buses that went down there were sort of hoping that it wouldn't work," recalled the physicist David Inglis (1905–1995). As they gathered at the test site, they did what they could to preoccupy their minds and calm their nerves. George Kistiakowsky, the chemist whose research team designed and fabricated the explosives that would initiate the chain reaction, drove into the desert "to look for rare cacti."⁶⁵ Alone atop the tower, Robert Oppenheimer gave the bomb—a giant metal ball covered with detonator knobs and electrical wire—his final inspection.

Figure 6. Los Alamos Scientists on Excursion in the Nearby Mountains

AIP Emilio Segrè Visual Archives, Segrè Collection.
Standing, left to right, Emilio Segrè, Enrico Fermi, Hans Bethe, Hans Staub, Victor Weisskopf; seated, Erika Staub, Elfriede Segrè.

The unearthly light that pierced the darkness early in the morning of July 16, 1945, evoked profound wonder in the atomic scientists, an intense adrenaline rush of delight and dread. The bomb was beautiful and terrible, alluring and repugnant, an expression of a sublime, transcendent power, at once marvelous and awful, that pulsed through the universe. "My God, it's beautiful," blurted an assistant to Julian Mack (1903–1966), as the enormous fiery cloud rose into the stratosphere. "No," countered Mack, "it's terrible." To Robert Serber, "the grandeur and magnitude of the phenomenon were completely breathtaking"; to George Kistiakowsky, it was how "the last millisecond of the earth's existence" would appear to people at some future end-time. "I thought that the explosion might set fire to the atmosphere and finish the earth," recalled Emilio Segrè, "even though I knew that this was not possible." The test was "wonderful," said David Inglis, but it made him apprehensive about the world's future. Robert Oppenheimer claimed that a line from the Baghavad Gita passed through his mind: "Now I am become Death, the destroyer of worlds." Victor Weisskopf recalled that "an aureole of bluish light" around the fireball reminded him of a medieval painting of Jesus ascending to heaven in a bright yellow sphere surrounded by a blue halo: "The explosion of an atomic bomb and the resurrection of Christ—what a paradoxical and disturbing association!"⁶⁶

FERTILE SOIL FOR KNOWLEDGE AND WISDOM

IN THE AFTERMATH of the Second World War, some American citizens judged the bomb to be a violation of nature and a denial of all that was good, beautiful, and true. As the United States committed ever more deeply to the atom's power, and as the poisonous consequences of that commitment spread across the land, their objections hardened and their numbers increased. Like Howard Zahniser, they came to believe that science had taken a wrong turn, and that there must be other means—poetry, literature, religion—by which to contemplate nature's mysteries. They embraced Rachel Carson's greatest work, Silent Spring, which explained how the insidious movement of Strontium 90 through the food chain modeled the infiltration of DDT along the same path. And they celebrated the sense of wonder as the root of a lifelong relationship to nature and the means to intellectual and moral development. "I sincerely believe," Carson wrote, "that ... it is not half so important to know as to feel. If facts are the seeds that later produce knowledge and wisdom, then the emotions and the impressions of the senses are the fertile soil in which the seeds must grow."⁶⁷

There is no reason to think that a Zahniser or a Carson could have known the intimate histories of the scientists responsible for building the bomb. Yet in retrospect, we can see that the path those physicists, chemists, and mathematicians followed to New Mexico did not just run through laboratories, particle accelerators, reactors, and other technologies that composed the world of instrumental science. Rather, the atomic scientists' path to the bomb also ran through many of the people, environments, experiences, and things that Zahniser and Carson held dear. It ran through children, mineral collections, oil drops on water, spinning tops, ants, beetles, worms, waves, salmon, eels, skunks, nature walks, and numbers. It ran through a father who taught his son to look and wonder and think for himself, and another who introduced his offspring to the question of whether an animal should be understood as a machine or as an organism enlivened by a vital essence. It ran through a Wyoming youngster who wondered if his wildflower-loving cowboy hero was, at heart, a sissy. It ran through sunsets, the full moon, meteor showers, and a club called Friends of the Stars. It ran through poetry, pine groves, and rural retreats with names like Heather House. It ran down deep canyons, through forests, along rivers and seashores, across fields covered with snow, into national parks, and up mountain peaks. That path, finally, ran through a strange, beautiful, wondrous place of vibrating, shimmering, energy-packed particles too small to see or feel yet nonetheless reflecting the face of God.

If we could transcend space and time, if we could rewind the tape, so to speak, and stand with Robert Oppenheimer as the shadows ascend the Sierra Oscura on the evening of July 15, 1945, we might better comprehend the bomb's origins in both reason and emotion. Although the atomic scientists employed theories of uncertainty and relativism, they were still Newtonians whose reductive, abstract, mechanistic method broke nature into parts for the purpose of description and analysis. Nowhere was their approach more starkly demonstrated than in the particle accelerator (popularly known as atom smasher), which used an electrical field to drive particles into a target, shattering them and allowing the scientists to observe the fundamental characteristics of matter. Yet for all its utility, the scientific method alone was not enough to establish the bomb's intellectual basis. The atomic scientists did not conduct their research simply because they could, or because it promised them wealth and power (indeed, before 1939, it promised them neither). They did it because it aroused their curiosity, allowed them to glimpse the fundamental forces shaping the universe, and gave meaning to their lives—in short, because it inspired their sense of wonder. They may have been relentless instrumentalists, but they were also childlike innocents enthralled by glittering particles. The sense of wonder compelled them to explore the recesses of those tiny pieces of matter; the scientific method enabled them to undertake the journey. The sense of wonder and the scientific method were a formidable combination. Together, they made possible the bomb.

Contemplating the atomic scientists and the bomb from the perspective of the mountains allows us to reflect on the moral implications of wonder. Perhaps the experience of that emotion made children better people and the world a better place, as the proponents of nature study believed. But wonder did not prevent some of those same children from growing up to build bombs. Indeed, as Oppenheimer and his compatriots showed, an abiding passion for nature actually enabled destructive ends. Still, atomic delight quickly gave way to a related emotional state, with a corresponding moral sensibility. To the extent that the atomic scientists felt dread, they also felt guilt, revulsion, remorse, and nausea, reactions that revealed their growing doubts that the bomb was the only, or best, solution to conflict. The drops on Hiroshima and Nagasaki deepened their misgivings and plunged some of them into psychological depression. Even those who believed that the bomb ended a horrible conflict had reservations about the weapon. They took solace in the theory that its destructiveness made war unwinnable and therefore obsolete. And they recognized that the family of nations must take concerted action to avert a dreadful fate.⁶⁸ It is tragic that a noble sentiment contributed to the production of a terrifying weapon; perhaps it is grounds for hope, if not comfort, that the dark side of that same feeling fostered a movement for restraint.

The atomic scientists' transit from delight to dread placed them in the company of an intellectual now famous for his awareness of the deep meaning to be found in a mountain. The ecologist Aldo Leopold (1887–1948) felt "a sense of wonder" when he pondered "the magnitude of the biotic enterprise." He felt it when migrating geese flew overhead, or when he contemplated the passenger pigeon, a "biological storm," "feathered tempest," and "chain reaction" that "roared up, down, and across the continent, sucking up the laden fruits of forest and prairie, burning them in a traveling blast of life." Although nature's explosive fecundity and diversity delighted him, a dreadful experience in New Mexico conditioned his outlook. His job had been to eliminate predators from the national forests. When he killed the animals—when he gunned down a mother wolf and watched "the fierce green fire" fade from her eyes—he became death, the destroyer of worlds. The slaughter changed him; he recoiled from extermination, rejected the reductive, mechanistic assumptions that informed it, and struggled to transform loss into wisdom. The murderer of wolves and other predators became their advocate. They and all other species, he said, had a necessary place in "the biotic community," the health and stability of which should become the ethical foundation for human actions. The mountain knew the value of the wolf; "thinking like a mountain" enabled people to appreciate that truth.⁶⁹

Oppenheimer and his colleagues were physical scientists, not ecologists, and atoms, not wolves, were the focus of their concerns. Nor did their experiences lead them to become outspoken environmentalists or ethicists. Yet the same brooding landform that instructed Leopold also taught them hard lessons. Like Leopold, they confronted the awful prospect of extermination, and like Leopold, they drew back. And much as Leopold doubted the machine and recognized the importance of the collective, so did they. When Oppenheimer foresaw the suicidal nature of atomic war, when he suffered guilt and confessed to having blood on his hands, when he agonized about the hydrogen bomb and eventually opposed it because he believed it to be an instrument of genocide, and when he stated his conviction that humanity's only hope lay in the binding obligations of the world community, he was closer to Leopold than either of them could have known.⁷⁰ Oppenheimer and other atomic scientists could find inspiration in a mountain. But somewhere on a lonely, windswept, vertiginous slope, they also learned, in their own way, to think like one.

As night falls on the Sierra Oscura, the atomic scientists beckon us to look past the mushroom cloud that has defined them. For a moment, at least, we might stand with Oppenheimer and survey the atomic landscape from an alpine vantage.⁷¹ In back of the fireball, the smoke, and the fallout we glimpse another story. The emotions that it evokes, the impressions that it makes, are fertile soil for knowledge and wisdom.

Mark Fiege is associate professor in the Department of History at Colorado State University, Fort Collins. He is completing a book on the environmental history of the United States.

NOTES

My thanks to Fredrik Albritton-Jonsson, Scott Casper, Mark Cioc, Nate Citino, Steve Fountain, Phyllis Hunter, Prakash Kumar, Peter Mallios, Janet Ore, Jared Orsi, Adam Sowards, Jennifer Sullivan, Louis Warren, two anonymous readers, the National Humanities Center, the CSU College of Liberal Arts, and the Niels Bohr Library and Archives, American Institute of Physics.

^1. Lansing Lamont, Day of Trinity (New York: Atheneum, 1965), 193.

^2. Marjorie Hope Nicolson, Mountain Gloom and Mountain Glory: The Development of an Aesthetics of the Infinite (1959; reprint, Seattle: University of Washington Press, 1997), describes the origins of the modern view of mountains. John Muir, The Mountains of California (San Francisco: Sierra Club Books, 1988), originally published in 1894, is a prominent work that emphasizes the wonder, delight, and beauty of mountains rather than the terror typical of the classic sublime as described by Nicolson.

^3. Mark Harvey, Wilderness Forever: Howard Zahniser and the Path to the Wilderness Act (Seattle: University of Washington Press, 2005), 46–47, quotation on 253.

^4. Although the term nuclear has become conventional and is more scientifically precise, people did speak of the atomic bomb or the atomic scientists, and thus I have chosen to retain that idiomatic usage.

^5. Carolyn Merchant, The Death of Nature: Women, Ecology, and the Scientific Revolution (1983; reprint, San Francisco: HarperCollins, 1990), describes the origins of modern science. For overviews of nuclear physics and the atomic bomb, see George Gamow, Atomic Energy in Cosmic and Human Life: Fifty Years of Radioactivity (New York: Macmillan, 1947); and Lawrence Badash, Scientists and the Development of Nuclear Weapons: From Fission to the Limited Test Ban Treaty, 1939–1963 (Atlantic Highlands, NJ: Humanities Press, 1995). For discussions of instrumental reason and its consequences, see Donald Worster, Rivers of Empire: Water, Aridity, and the Growth of the American West (New York: Pantheon, 1985), 54–58; and Michael Sherry, The Rise of American Air Power: The Creation of Armageddon (New Haven: Yale University Press, 1987), 219–55.

^6. Werner Heisenberg, "Quantum Theory and Its Interpretation," in Niels Bohr: His Life and Work as Seen by His Friends and Colleagues, ed. Stefan Rozental (New York: Interscience Publishers, 1964), 94–95, quotation on 95. Oppenheimer contrasted Paul A. M. Dirac's mathematical approach to thinking and communicating with Bohr's verbal method. J. Robert Oppenheimer, interview by Thomas S. Kuhn, November 20, 1963, 1, Niels Bohr Library, Center for History of Physics, American Institute of Physics, College Park, Maryland (hereafter NBL).

^7. Paul A. M. Dirac, The Development of Quantum Theory (New York: Gordon and Breach, 1971), 13–14, 19; Werner Heisenberg, Across the Frontiers (New York: Harper and Row, 1974), 163. See also Subramanyan Chandrasekhar, "The Pursuit of Science," Minerva 22 (1984): 410–20.

^8. Albert Einstein, "Religion and Science," New York Times Magazine, 9 November 1930: 1–4, in Albert Einstein, Ideas and Opinions (New York: Modern Library, 1994), 39–43, quotations on 41, 42; Henry Margenau, "Einstein's Conception of Reality," in Albert Einstein: Philosopher-Scientist, ed. Paul Arthur Schilpp (New York: Tudor Publishing, 1951), 249; Rebecca Goldstein, Betraying Spinoza: The Renegade Jew Who Gave Us Modernity (New York: Schocken, 2006), 61–62; Abraham Pais, Einstein Lived Here (New York: Oxford University Press, 1994), 186. See also Einstein's insightful discussion of wonder in "Autobiographical Notes," in Albert Einstein: Philosopher-Scientist, 8–11; Isidor Rabi's thoughts on the same topic in Robert P. Crease and Charles C. Mann, The Second Creation: Makers of the Revolution in Twentieth Century Physics (New York: Macmillan, 1986), 59–61; Ken Wilber's Quantum Questions: The Mystical Writings of the Great Physicists (Boston: Shambhala, 2001), which argues that "wonderment" (p. xii) moved the atomic scientists beyond quantum physics toward an awareness of ultimate reality; and Freeman Dyson, "The Scientist As Rebel," in Nature's Imagination: The Frontiers of Scientific Vision, ed. John Cornwell (New York: Oxford University Press, 1995), 10, in which the author observes that "the chief reward for being a scientist is not the power and the money but the chance of catching a fleeting glimpse of the transcendent beauty of nature." On Einstein's indirect relationship to the bomb, see Andrew Robinson, Einstein: A Hundred Years of Relativity (New York: Harry N. Abrams, 2005), 191–96.

^9. On the history of wonder and the Enlightenment emphasis on mechanical objectivity, see Lorraine Daston and Katharine Park, Wonder and the Order of Nature, 1150–1750 (New York: Zone Books, 1998), 13–20, 303–68; Lorraine Daston and Peter Gallison, "The Image of Objectivity," Representations 40 (Fall 1992): 81–128; Lorraine Daston, "Objectivity and the Escape from Perspective," Social Studies of Science 22 (1992): 597–618; Lorraine Daston, "Enlightenment Calculations," Critical Inquiry 21 (Autumn 1994): 182–202; and Bruce Bower, "Objective Visions: Historians Track the Rise and Times of Scientific Objectivity," Science News 154 (5 December 1998): 360. The work of Daston and Park is one of the more prominent expositions of a recent scholarly trend; see also, for example, Caroline Walker Bynum, "Wonder," American Historical Review 102 (February 1997): 1–26. Wonder has close ties to the sublime. For one of the classic treatments, see Edmund Burke, A Philosophical Enquiry into the Origin of our Ideas of the Sublime and Beautiful (London: Penguin Books, 2004), a reprint of the book's second edition, published in 1759. For a more recent version, see David E. Nye, American Technological Sublime (Cambridge: MIT Press, 1994). J. F. Carlson and J. R. Oppenheimer, "On Multiplicative Showers," Physical Review 51 (15 February 1937): 220–31, is a typical scientific paper.

^10. Peter Gallison, "Objectivity is Romantic," American Council of Learned Societies Occasional Paper No. 47, 1 May 1999, at http://www.acls.org/op47-3.htm; and Werner Heisenberg, "The Idea of Nature in Contemporary Physics," in The Physicist's Conception of Nature (1958; reprint, Westport, CT: Greenwood Press, 1970), 7–31, suggest the limitations of objectivity and the need for creative thought outside conventional methods. Freeman Dyson contends that a reductively mathematical approach leads to intellectual sterility. See his discussion in "The Scientist As Rebel," 5–8.

^11. According to Burke, A Philosophical Enquiry, 114, "we become amazed and confounded at the wonders of minuteness; nor can we distinguish in its effect this extreme of littleness from the vast itself."

^12. See, for example, Einstein, "Autobiographical Notes," 8–11. The expression of wonder in popular science continues; notable examples include, among many other titles, Carl Sagan, Broca's Brain: Reflections on the Romance of Science (New York: Random House, 1979), especially 137–46; and Lawrence M. Krauss, Atom: An Odyssey from the Big Bang to Life on Earth ... and Beyond (Boston: Little, Brown, 2001), especially 285–86.

^13. Rachel Carson, The Sense of Wonder (New York: Harper and Row, 1965), 42 (quotation), 45. Carson's essay first appeared as "Help Your Child to Wonder," Woman's Home Companion (July 1956): 25–27, 46–48, 89. Carson was only one among many biologists and nature writers to address the theme. Charles Darwin (1809–1882), for example, wrote eloquently of "endless forms most beautiful and most wonderful" in The Origin of Species. Charles Darwin, The Origin of Species by Means of Natural Selection, ed. J. W. Burrow (1859; reprint, London: Penguin Books, 1985), 435–60 (quotation on 460) and passim. See also, for example, Edward O. Wilson, The Diversity of Life (New York: Norton, 1992); George Levine, Darwin Loves You: Natural Selection and the Re-enchantment of the World (Princeton: Princeton University Press, 2006); and Thomas Dunlap, Faith in Nature: Environmentalism as Religious Quest (Seattle: University of Washington Press, 2004), 14–41.

^14. Although Carson's concept emphasized living things, she acknowledged that forms of nonliving nature, such as stars and constellations, also inspired the sense of wonder. See Carson, Sense of Wonder, 54–55. Stars and constellations, of course, were the very sorts of nonliving physical phenomena that also evoked wonder in the atomic scientists. Conversely, for a famous physicist's expression of wonder at earthworms, weeds, insects, and other quotidian forms of nature, see Peter A. Bucky, The Private Albert Einstein (Kansas City: Andrews and McMeel, 1992), 15. Carson suggested that affinity for nature, especially living nature, was innate. Stephen R. Kellert and Edward O. Wilson, eds., The Biophilia Hypothesis (Washington, DC: Island Press, 1993), centers on a similar conviction, as articulated by Wilson.

^15. On this point see Werner Heisenberg, "The Meaning of Beauty in the Exact Sciences," in Across the Frontiers, 182.

^16. J. Samuel Walker, "Recent Literature on Truman's Atomic Bomb Decision: The Search for a Middle Ground," Diplomatic History 29 (April 2005): 311–34, a historiographical treatment of one important part of the literature on the bomb, suggests the field's overall depth and complexity. For the standard account of the history of physics in the United States, see Daniel J. Kevles, The Physicists: The History of a Scientific Community in Modern America (1977; reprint, Cambridge: Harvard University Press, 1995).

^17. John Wills, "'Welcome to the Atomic Park': American Nuclear Landscapes and the 'Unnaturally Natural,'" Environment a