The Nature-Study Idea

Front matter

AND RELATED WRITINGS

A VOLUME IN THE SERIES

THE LIBERTY HYDE BAILEY LIBRARY Edited by John Linstrom

Contents

List of Illustrations ix Foreword by David W. Orr xi Introduction 1

Bringing Education to Life and Life to Education: Contemporary

Relevance of Bailey’s Nature-Study by Dilafruz R. Williams 10 “It Is Spirit”: The Genesis of The Nature-Study

Index

227 229 236

243 243 247 250 255

261 265

Rw NH Re

ILLUSTRATIONS

. Central School, South Haven, Michigan

. Advertisement for Nature Portraits

. Staff of The College Speculum

. Faculty and students of the Nature-Study Summer School at Cornell

. Advertisement for The Nature-Study Idea . Advertisement for The Little Nature Library, June 1903 . Advertisement for The Little Nature Library,

September 1903

. Whittier School students on a field trip studying plants,

Hampton, Virginia

. How a man impressed a child

. What a little girl saw

. Squash plant a week old

. Squash plant that has brought the seed-coats out of the ground x

25: 26. 27.

Illustrations

Germination just beginning

The root and peg

Third day of root growth

The plant breaking out of the seed-coats The operation further progressed

The plant just coming up

The plant liberated from the seed-coats The plant straightening up

The true leaves developing

Marking the root

The root grows in the end portions

The marking of the stem, and the spreading apart of the marks

Floor plan of the Cornell Rural School-house Front view of the Cornell Rural School-house Rear, and work-room end of the Cornell Rural

School-house

241 272 273

Foreword

In The Nature-Study Idea (1903), Liberty Hyde Bailey proposed adding the study of nature to school curricula not just to instill knowledge about the natural world but as a method to awaken the child’s spirit and inform their worldview.' The aim was to enable the children to develop a thoughtful and competent love for nature that grew from their curiosity about the natural world. “The first essential,” he wrote, “is an intense love of nature,” and all else would follow in due course, including scientific knowledge and ethical awareness (Part I, Chapter I, this volume; hereafter, “I.I”). That intense love of nature grew best out of doors and on the child’s terms. Teachers facilitated, a child’s curiosity prevailed over curriculum, and disciplines were boundaries to be crossed. The point was to nurture a wider context for living in harmony with nature. Nature-study, in Anna Botsford Comstock’s words, was to “be so much a part of the child’s thought and interest that it will naturally form a thought core for other subjects quite unconsciously on his [or her] part.”* The nature-study movement aimed to enable an individual to use their senses, keep their eyes open, and awaken to “the beauty as well as to the wonders which are there.”?

xii Foreword

Bailey’s view of nature was a precursor to what was later called “deep ecology,” in which nature was given profound consideration, if not legal rights. The “notion that all things were made for man’s special pleasure,” he wrote, “is colossal self-assurance” (M.NI). As an antidote to the triumphalism of his time, Bailey proposed “that all people, or as many of them as possible, shall have contact with the earth and that the earth righteousness shall be abundantly taught.”* That curriculum, however, began in humility tempered by reverence for life—a precursor as well to Albert Schweitzer’s philosophy and that of the tribe of environmental ethicists to come.

The nature-study movement aimed beyond children to farmers and the improvement of rural life. “No thoroughly good farming,” he wrote, “is possible without this same knowledge and outlook. Good farmers are good naturalists” (I. VII). Further, he regarded “extend[ing] the agricultural applications of nature-study” as the “special mission” of an agricultural college, including his home institution, Cornell University (I. VII). Bailey’s views about farming and rural improvement also preceded those of others, including Louis Bromfield and Aldo Leopold.

The nature-study movement that “began to take form [. . .| from 1884 to 1890” was roughly coincidental in time with the early work of the philosopher, John Dewey (I.I). Bailey and Dewey both intended to reorient education to place and locality, and both considered the home and neighborhood as the foundation of democracy.’ At the time, most Americans lived on farms or in small towns and knew the rigors of rural life. America, however, was on the move, busy manifesting its destiny, “winning the West,” conquering the few remaining recalcitrants, building cities, taking the first steps to an overseas empire, industrializing with a vengeance, building vast corporations, and, for a few, amassing huge fortunes. Those like John Muir and John Burroughs, and the rare politicians like Teddy Roosevelt and Gifford Pinchot who had second thoughts about the juggernaut sweeping across the American land, put up little more than speedbumps on the road to our current predicament. The Country Life Commission, appointed by Roosevelt in 1908 and chaired by Bailey, sought to focus on the needs of rural people and towns left behind. Despite several notable successes, including the Smith-Lever Act of 1914, which created a national agricultural extension program through the land-grant universities, the country life movement was no match for capital-intensive, large-scale agriculture. Capitalism swept across rural America like a

Foreword xiii plague, devouring people, land, forests, wildlife, waters, small farms, and once-vibrant small towns alike. Urban sprawl, commercialism, and interstate highways did the rest. As a result, the rural life movement foundered, in Paul Sears’s words, on “our utter failure to see the connection between the word ‘Conservative’ and the word ‘Conservation.’ ”°

The idea of nature education, however, has not perished; it was too good and too necessary to go away. Bailey, Comstock, and others are largely forgotten, but their legacy and ideas live in the work of environmental educators, environmental organizations, and local land preservation organizations and in organizations such as the Children and Nature Network, inspired by Richard Louv.’ But the challenge is greater than Bailey and his contemporaries could have foreseen. Most children now grow up in urban areas and live indoors, all too often addicted to their smartphones, their free time filled with the internet and a thousand distractions that capture their attention and minds.® As a result, fewer now spend much time out of doors or live in places where contact with nature is routine, necessary, and instructive.

When Bailey passed from this Holy Earth in 1954 at the age of 96, CO, in the atmosphere was 313 ppm. As I write (March 2022), it is near 420 ppm. To that number we should add another 50-75 ppm of other heattrapping gases measured in CO, equivalent units, putting us close to 500 ppm higher than any time in the past two to five million years. In 1954, the United States stood astride the world like that proverbial colossus. Now, not so much. Bailey’s early years were the era of the “robber barons.” We too have robber barons, just as predatory or even worse. A half dozen U.S. oligarchs have more wealth than the bottom 50% of the population, and the gap between the richest and the rest continues to widen. In 1954 there were ~5.6 million farms in the United States, and the average farm size slightly more than two hundred acres. Presently we have two million farms, but production is dominated by eighty thousand mega farms. The diversified small farm of Bailey’s day cannot compete with highly subsidized, chemicalized, and capital-intensive agribusiness. Perhaps one-third or more of the topsoil on American farmland in 1900 has since washed or blown away, but no one knows for certain. Excess fertilizer runoff down the Mississippi has created a dead zone in the Gulf of Mexico the size of New Jersey. Another dead zone is growing between xiv Foreword our ears, a national deficit of the kind of knowledge and sensibility that was the core of nature-study. And not the least, our oil-soaked democracy seems to have stalled out, our institutions corrupted by too much unaccounted money and elected officials with too much ambition and too little integrity. Too much venom, too little kindness. We are vexed and paralyzed, unable to solve even the most basic public problems.

Bailey, a man who thought a great deal about connectedness, would have noticed those connections between land health, human well-being, oil, rapid climate change, and the shabbiness of our public affairs. In What is Democracy? he wrote, “A nation of selfish individuals is never a democracy. A democratic society is impossible until its population is possessed of the spirit of helpfulness to others.” Like Thomas Jefferson, Bailey believed that “democracy rests on the land” but never on a landed aristocracy, let alone a land-owning corporatocracy.'° Like Tocqueville, Bailey regarded the “habits of heart”—the inclinations and dispositions nurtured on farms—as one of “the great sources of citizenship” and the foundation for “a permanent society.” “The farmer,” he wrote, “is the fundamental fact in a democracy.”!! But he regarded growing food for urban society as secondary to the role of farms and rural communities in providing a steady flow of young people recruited into our national life—a citizenry disciplined by hard work and frugality; knowledgeable about soils, animals, wildlife, weather, and water; and adept at solving practical problems with home-grown ingenuity. Bailey’s vision also included partnerships between the city, country towns, and farms that provided a steady supply of food while strengthening common bonds.'3

Troubled by the destruction wrought by World War I, Bailey proposed an alternative to worldwide militarism in the form of a “cooperative effort for the public good, rather than for the public destruction [. . . and] the shameful wounding of the planet.”'* He proposed instead the “constructive occupancy” and “reconstruction of the earth” with rural people in the lead and organized as “a Society of the Holy Earth. Chapters and branches it may have, but its purpose is not to be [an] organization [. . .]. Its principle of union will be the love of the Earth, treasured in the hearts of men and women.”! Later, those vague ideas became manifest in the Peace Corps, VISTA, and other organizations providing opportunities for public service for the young and idealistic.

Foreword xv

What can be made of this remarkable man as a scientist, writer, and advocate? More important, what should we do with his legacy in our own time? First, Bailey is among the most prescient critics of industrial society, including Henry David Thoreau, George Perkins Marsh, and especially John Wesley Powell, who warned that settlement of arid regions of the West should be organized by watersheds rather than the hydrological fantasies of land speculators. Second, Bailey cannot rightly be dismissed as a quaint anachronism, a throwback to some long-gone era. I think it is more accurate to describe Bailey as a “throw forward,” a visionary who saw more clearly than most what must be done to make America more than a trial balloon, as Aldo Leopold put it. Bailey understood the importance of farming and farm life, and the necessity of vibrant and prosperous rural areas, for the durability of any civilization. He knew how important kindness, neighborliness, and cooperation were to the democratic temperament. He knew that democratic societies can be sustained only by ecologically literate, practically competent, and community-minded people. Nature-study, in other words, was not just a curriculum for children but an essential part of democracy,

revitalized rural areas, and a prosperous and permanent agri-culture.'® I believe that those traits have increased in value, not the least because our generation and those to come face a rapidly warming climate and the prospect of cascading systemic failures that threaten the ecological and material underpinnings of civilization. The man revealed in his life and writings would not have equivocated in the face of the long climate emergency ahead. Rather, I think he would have set about to rebuild the frayed foundations of rural America and worked to make sustainable rural prosperity a reality. It is not difficult to imagine a Liberty Hyde Bailey now enlisting liberal arts colleges and land-grant universities, including his own, to the cause of “universal service” extended to include future generations, and in that effort giving birth to a post-extractive agriculture that would not mine soils, groundwater, people, or communities; an agri-culture that would sequester carbon in soils and would dependably render sunlight into plant tissue, animal flesh, and electrons; an agri-culture built not on corporate power and high finance, but ingenuity, devotion, skill, and the authentic patriotism of people who know that the Earth is indeed Holy and that it can be redeemed only by loving care and practical competence. David W. Orr

Introduction

A book like [The Principles of Agriculture| should be used only by persons who know how to observe. The starting-point in the teaching of agriculture is nature-study,—the training of the power to actually see things and then to draw proper conclusions from them. Into this primary field the author hopes to enter; but the present need seems to be for a book of principles designed to aid those who know how to use their eyes.

Liberty Hyde Bailey, preface to The Principles of Agriculture (1898), p. viii

Liberty Hyde Bailey would realize his ambition to enter “this primary field” just five years after writing that preface to The Principles of Agriculture in what would prove to be one of his most influential and enduring texts, The Nature-Study Idea: a book not only for “those who know how to use their eyes,” but one that would help others to see, as well. A rising leader and visionary in the field of agricultural education— a new concept then emerging from the series of land-grant college acts meant to make higher education relevant and accessible to the majority of Americans who were still farmers at that time—Bailey believed that a better, more sustainable future for agriculture and rural life would not come about simply through scientific investigation and improved farming methods. These methods would be needed, such as crop rotation to sustain and build soil fertility, and he outlined them in books such as The Principles of Agriculture (it comes as no surprise, in fact, that a full third of that book was devoted to the health of the soil). But more fundamental and more pressing than any program of scientific advancement would be an educational model oriented toward the complexity of the natural world and rooted in a sense of wonder, an outlook best nurtured in the early elementary years but important for all of us, throughout our lives. For this reason, nature-study was much more than science, even as it embraced a scientific outlook; in fact, Bailey argued, nature-study “is not science. It is not knowledge. It is not facts. It is spirit. It is an attitude of mind. It concerns itself with the child’s outlook on the world” (Part I, Chapter I; hereafter, I.I). He believed that such an “outlook to nature,” as he would call it in the title of his next major book, would become the best safeguard of a more resilient, sustainable agriculture.

Today we understand that agricultural crises, like the horrifically rapid loss of our planet’s topsoil (that precious living realm of microbial ecosystems that remains so mysterious and so crucial to our ability to feed ourselves as a species) are inextricably bound to the even larger crisis of climate change.' And as David W. Orr notes in his foreword to this volume, our ability to collectively address these large, systemic crises relates directly to the health of democratic systems around the world—systems that are also undergoing unprecedented strain, sometimes for good reasons but too often due to the oligarchic ambitions of the few. How do we strengthen democracy (a state of society that Bailey felt had never been fully reached but that we should constantly strive for)* and at the same time mobilize every possible resource toward the remediation of climate change and a truly regenerative future? Scientific facts alone will not push the massive political shifts and reallocation of resources that we need. What progress we have seen in recent years has come about when those facts were mobilized by an increasingly powerful cultural movement demanding change—a diverse and coalitional movement decades in the making that needs to accelerate right now.

For Bailey, the emergent science of evolution provided a striking affirmation of “the simple wisdom of the fields” that he felt he had grown up with in nineteenth-century rural Michigan: the awareness that, as he writes in The Nature-Study Idea, “all things are of kin” (ILI), and that this awareness of our deep familial kinship with all life requires of us a new kind of interspecies ethics, a responsibility to the more-than-human world. In The Holy Earth (1915), he would memorably describe the need for “a new hold” on our place in nature, on a planet that “is not exclusively man-centred; it is bio-centric.” This affirmation from the lessons

Introduction 3 of evolution still speaks to us today, and the science of climate change only intensifies our awareness of our deep contingency in the web of life (that the earth “is not exclusively man-centred”) at the same time that it drives home just what a different order of magnitude the impact of our species on the planet is than that of any other. For Bailey, this relational awareness had the potential, once society was truly awakened to it, of revolutionizing every aspect of our social life, of reintegrating country and city, of fitting our homes, farms, and communities to a finer-tuned sympathy with nature. A leader and an organizer himself, particularly from his seat as Experiment Station Director and later the founding Dean of the College of Agriculture at Cornell University, he then set about to think through how this awareness could actually be spread throughout a culture, in a process identified by Bailey scholars Paul A. Morgan and Scott J. Peters as “worldview transition.”* Bailey believed that the work of such worldview transition would fundamentally rest upon a renewed education—an education rooted not in books, or in merely learning the names of things or collections of facts, but in “the simple wisdom of the fields,” experienced directly and with the whole child in mind. Nature-study wasn’t just natural science adapted for young children; it was part of “a soul-movement” (ILI).

Such a soul-movement would strengthen the bonds of democracy, both through bringing people together (with each other and with our nonhuman kin) and through challenging the injustices that have kept us apart. A democratizing education would mobilize knowledge in ways that empower communities to adapt and, when necessary, to develop a public mandate for change. Bailey knew that we would need more than knowledge or facts to reform our outlook to nature, and he also knew that the natural world itself had much more to teach us than scientific knowledge alone. Science is a human institution, after all; the more-than-human world speaks a more capacious set of languages, and nature-study would open the senses to these multiple ways of coming to know “the simple wisdom of the fields,” informed but not limited by the formal sciences. The humanities and the arts would point the way to “the poetic interpretation of nature” (II.VI) and the development of an ethic of environmental stewardship, from the individual to the social level. No academic discipline should be elevated above the others in the education of the whole child—no snappy acronyms or corporate educational marketing campaigns should restrict the child’s exploration (he writes of the danger of “catch-words” in The Science Element in Education, in Related Writings, this volume)—and all of these disciplinary endeavors would come to nothing, pedagogically, if they failed to root themselves in firsthand, experiential learning in the real world, out of doors. Nature would provide the check to human (and disciplinary) arrogance.

Moreover, Bailey argued, “The outlook to nature is the outlook to optimism.”* Nature-study would be the means to raise happier, as well as more well-rounded and more ecologically minded, children. Teachers would find it uplifting as well, and The Nature-Study Idea owed its success in its own time largely to its lasting inspirational and instructive value to the art of teaching.

The book staked out the intellectual territory for an influential and pedagogically powerful vision for educational reform, and that vision continues to challenge current trends. Bailey combined an emphasis on experiential learning with a distinctly ecological understanding that the best way to learn about the world, how it works, and how we fit within it, is by observing plants and animals in their own habitats. After all, as he points out in The Humanistic Element in Education (in Related Writings, this volume), “Man is as much a part of nature as is a pigeon or a trillium.” He had known since his childhood on the farm that children were active agents in their ecosystems—and so were teachers, and so were the gardens that began rapidly to proliferate across turn-of-the-century schoolyards under the influence of the nature-study movement. Bailey was never one to impose an artificial divide between the human world and the rest of nature, instead always insisting on the human place as a species embedded within natural systems, with human actions not only influencing but also influenced by surrounding environments (for better or worse, domesticated or wild). The child should feel and be encouraged to explore that sense of relationship with and embeddedness in her more-than-human neighborhood, he insisted, and that neighborhood should extend to untamed nature (how many birds, insects, and weeds does even the city child pass each day on the way to school!) as well as to the working landscapes of the community. In Bailey’s primary sphere of concern, and that of most Americans a century ago, those working landscapes were the farms and gardens of the open country, but he also argued that nature-study should not be confined to rural areas only.

Introduction 5

The goal of this ecological (Bailey would simply say “natural”) education was not primarily to produce academic specialists in any field but rather “the establishment of a living sympathy with everything that is” (What Is Nature-Study?, in Related Writings, this volume) in order “to enable every person to live a richer life, whatever his business or profession may be” (I.I). Such a goal stands in stark contrast to persisting obsessions with the merely testable, quantifiable, and measurable. In his 1909 revision of the book, Bailey responded to requests for “statistics” quantifying the impact of nature-study, writing that the assumption that such numbers could even be given misses the very purpose of the nature-study movement, which is to set pupils at work informally and personally with the objects, the affairs and phenomena with which they are in daily contact. There are very many teachers and very many schools, and very many pupils, who have a new outlook on life as the result of nature-study work; but if I could give a statistical measure of the nature-study movement, I should consider the work to have been a failure, however large the figures might be. (LI)

If he were writing today, Bailey would undoubtedly have something to say about the pedagogical impacts of high-stakes testing and curriculum cramming, motivated by a cultural obsession with “statistical measures” that so often leave little room for the development of curiosity and discovery— in other words, for education, for the development of the child, a result that cannot be captured numerically.

In beginning with the common things of the neighborhood, which are relevant to the child’s life because they constitute the child’s world, nature-study works against superficiality in education. By basing itself in the concrete and exploratory experiences of the child, Bailey argued that it also provided a more reliable model for understanding the world than the second-hand information in textbooks, which at the time were marketed aggressively to teachers, often by dubious salespeople interested in turning a quick profit on the burgeoning field of public schooling, in much the same way that web-based educational applications are often marketed to teachers and administrators today.’ “Nature, not books,” was the famous dictum of nature-study teachers taken from the work of Louis Agassiz, and nature was free to all right outside the schoolhouse door. Simple, entertaining pamphlets to help direct the activities and point of view were free to whomever requested them from Cornell, but they always sought to send the teacher and students away from the pamphlets themselves and out into the world. And anyway, the technological tools that today can connect children to seemingly infinite information (and disinformation), like the books of Bailey’s time, will always run the risk of alienating students, rather than nurturing productive connections, if they are not accompanied by a more foundational grounding in the world the children actually inhabit.

The potential ecological impact of raising each generation to be more sensitive than their parents to the realities of the natural world has grown only more significant for us on a climate-changed planet. In 1903, Bailey already saw such work to be foundational to a culturally and ecologically sustainable future. In response to a historical moment in which farmers were being pushed off the land by a series of droughts and a set of economic policies that prioritized consumers over producers—problems more acute today than then and less well appreciated—Bailey was able to marshal state funding for a nature-study program, of all things, in the belief that the mere dissemination of information alone would not solve the underlying problems facing agriculture. The future would bring more droughts, and in the meantime economic policy would need to be rewritten, but by cultivating a sense of curiosity and wonder and by empowering students (many of whom, in that day, would go on to become farmers) to investigate problems for themselves, nature-study provided the necessary foundation for a healthy “rural civilization,” as he sometimes called it, in which better methods would be discovered every day on working farms and in which farm life would be not only economically viable but intellectually stimulating, and thereby fulfilling. Nature-study planted the seeds for improved farming, but more importantly, it also planted the seeds for a more rewarding and fuller life on the land.

That this fuller life was meant for everyone was implied by the grassroots character of the nature-study movement itself. Because they emerged primarily from the work of teachers in the public schools, nature-study methods were developed to be simple, affordable, time effective, and accessible to the greatest number of students. Bailey takes pains in The Nature-Study Idea to trace the movement’s evolution and cite the work of many individuals working in their local communities for the good of their

Introduction 7 children—ordinary educators and administrators, many of whom would otherwise have been lost to history. Moreover, it was a movement led largely by women, and Bailey appointed women, including most notably Anna Botsford Comstock, to lead the effort at Cornell in prominent positions at a time when university professors were almost exclusively men. In the South, nature-study was taken up by Black educators like Booker T. Washington and George Washington Carver, who argued for it largely along the same lines that their white northern counterparts did: as a pedagogical approach that encouraged independent thinking, exploration, and sympathy with the natural world, leading children to greater self-sufficiency and intellectual satisfaction with rural life. And nature-study quickly became popular in cities like Chicago and New York, where vacant lots were transformed into massive school gardens and “field trips” (an invention of the nature-study movement) provided engaging opportunities for learning as well as escapes from the stiflingly overcrowded classrooms characteristic of urban public schools of the era. As a democratizing ideal, nature-study was understood to benefit anyone lucky enough to encounter it in school or at home, and it was the mission of the movement’s leaders that nature-study reach as many children as possible. (More on this history and how Bailey fits into it in my essay “It Is Spirit,” this volume.)

Bailey shared this belief that nature-study was universally needed in his day, both to provide children with a lifelong balm from the increasing complications of modern life and to work as a corrective to the domineering mind-set that placed humans apart from and above nature—a mind-set that led to what he would later call the “habit of destruction.”° He could not have foreseen the extent of that destruction in those early days of climate science, although the realities of species extinction were increasingly clear to him. The last passenger pigeon would die eleven years after the publication of The Nature-Study Idea, and he could still remember when their migrations would darken the skies of his childhood farm home for days. Moreover, Bailey could see, more clearly than many today, that questions of ecology and conservation were inextricable from questions of education, community organization, the relationship of country to city, and the functioning of democracy. Bailey would write more about each of these topics over the course of his career as a leading agrarian thinker and reformer, but he always maintained that the root of all possible reform in any of these arenas would be nature-study.

This edition of The Nature-Study Idea seeks to reintroduce Bailey’s classic work to best speak to the needs of contemporary readers—teachers, parents, students of education and of the environment, activists, and scholars of the many intersecting fields that Bailey’s work engages. David W. Orr’s foreword speaks to the urgency of nature-study in the present moment of climate catastrophe and the fraying of democracy, and Dilafruz R. Williams’s essay puts Bailey’s words into the context of current pedagogical discourses in the field of education. Following these opening essays is a lengthier historical sketch, titled “ ‘It Is Spirit’: The Genesis of The Nature- Study Idea,” which tells the story of Bailey’s educational philosophy and many of the influences that went into his book, from a beloved childhood teacher to a college mentor with whom he would come into sharp disagreement. Then, following a note on the texts, we present the final, 1911 fourth edition of The Nature-Study Idea in its entirety, respecting all the changes Bailey made over the course of four editions to one of his most important books. The text features extensive endnotes for those interested in engaging Bailey’s words more deeply, from short biographical sketches of individuals named (who range from classical Greek philosophers to rural school principals) to minor passages eliminated from the first edition in Bailey’s later revisions. After the full text of the fourth edition comes a series of larger sections cut from the first edition, which, along with the shorter passages supplied in the endnotes, makes this text the most complete edition of the work available. Then a section of contemporary book reviews of The Nature-Study Idea helps fill in the picture of the breadth and quality of the book’s reception, both in its first edition with Doubleday and the revised third edition with Macmillan, representing perspectives ranging from those of literary critics to education professionals and sociologists. Finally, a selection of Related Writings provides a number of important, shorter nature-study texts written by Bailey, spanning the years 1896 to 1918, that help to fill in the picture of Bailey’s nature-study idea and its evolution over time, from the founding of Cornell’s nature-study work, through the original 1903 edition and into the period shortly before he began preparing the major 1909 revision, and then into his retirement and the period in which he was producing his important philosophical series, The Background Books: The Philosophy of the Holy Earth.