Earth Day will be celebrated on April 22. An annual event begun in 1970, it is, in the words of anthropologist Margaret Mead, “devoted to the preservation of the harmony in nature.” Before and since that first occasion, spaceflight and the environmental movement have been deeply entwined, shaping how we think about Earth as home as well as our responsibilities to sustain that home.

The first Earth Day featured community events in 200 U.S. cities, with large gatherings in New York City and Philadelphia. In Manhattan, the city closed Fifth Avenue to throngs of marchers.  In Philadelphia, large outdoor crowds heard speeches by poet Allen Ginsburg and consumer activist Ralph Nader. From a small office in New York, leaders of Earth Day orchestrated a national “teach-in.”  It sought to raise public awareness of environmental issues and show how individuals could begin in their daily lives to improve the environment—whether to make less trash or use less energy. More than 2,000 colleges and 10,000 high schools around the country organized teach-ins or other community events—all aimed at stimulating a grassroots movement for the environment.  The 1960s civil rights movement and the Vietnam anti-war protests served as models.

Air pollution was a particular focus of the event, as this poster from Washington, DC, shows.

 

Such imagery encapsulated the basic message of Earth Day: “Think Globally, Act Locally,” a phrase the event introduced into public dialogue.  Large-scale air pollution, for example, could have planetary consequences, but individuals could collectively address such problems in their daily life by driving less or cleaning up sources of pollution.

But how did “thinking globally” become persuasive to so many people in the United States and elsewhere? To believe there was a strong connection between our individual actions and the health of the entire planet?

There was an outpouring of writing in the 1960s that made this connection—and much of it drew on space-age perspectives and metaphors. Foremost perhaps was architect and polymath Buckminster Fuller’s 1968 book, Operating Manual for Spaceship Earth. But one image made this linkage seem viscerally obvious: Earthrise, taken in December 1968 by Apollo 8 astronaut William Anders, as he and his fellow astronauts circled the Moon. This well-known image long has been celebrated in the environmental movement—on a par as a cultural icon with the 1972 Apollo 17 Whole Earth image.

 

Soon after Apollo 8’s return, NASA released the image. It quickly gained specific meaning.  On seeing the image, poet Archibald MacLeish immediately penned a poem, “Riders on Earth Together, Brothers in Eternal Cold,” widely distributed and quoted. For MacLeish, the image provided a radical perspective, a shift in consciousness: “to see the earth as it truly is, small and blue and beautiful in that eternal silence where it floats, is to see ourselves as riders on the earth together, brothers on that bright loveliness in the eternal cold -- brothers who know now they are truly brothers.”  This emphasis on common humanity made emphatic by our planetary home’s fragility in the vastness of space became the dominant way of understanding this powerful image.

The combined message of image and poem came at a particularly auspicious moment—just as environmentalism gained strength as a political movement. Mere weeks after Apollo 8, Richard Nixon began his first term as president. In the last section of his inaugural address, he specifically highlighted the Apollo 8 mission and quotes from MacLeish’s poem, echoing its message by offering that “our destiny lies not in the stars but on Earth itself, in our own hands, in our own hearts.”  Such feel-good language soon translated into government action. In 1970, Congress established the Environmental Protection Agency and the National Oceanic and Atmospheric Administration. In presenting the rationale for the latter, he again returned to the sentiments of the image and the poem and the need to understand “the total environmental system upon which we depend not only for the quality of our lives, but for life itself.” The evocation was even stronger, when, in 1972, he announced the Space Shuttle program and what it would accomplish: “Views of the Earth from space have shown us how small and fragile our home planet truly is. We are learning the imperatives of universal brotherhood and global ecology learning to think and act as guardians of one tiny blue and green island in the trackless oceans of the Universe.”

By the time Apollo 17 captured Whole Earth in 1972, Earthrise had already helped to shift U.S. culture and politics as well as our sense of humanity’s relationship to its home. In the years after, such perspectives led NASA to take up systematic study of the “total environmental system upon which we depend.”  Today, 28 different science missions are active, studying different aspects of the Earth as a physical system.

As we think about Earth Day this year, should we be optimistic or pessimistic about our human future on Earth? The first Earth Day embodied this very tension. Could individual or collective action reduce the impacts of modern life on the environment? That tension has persisted. This year the Smithsonian is sponsoring an Earth Optimism Summit (https://earthoptimism.si.edu/ ) to show the possibilities of constructive action. Whatever the future holds, the environmental movement and space-based perspectives have remade our sense of responsibility to our fellow humans, whether near or distant from us, and to the planet on which we all live. The history of Earth Day is a story of the choices we have been willing to make and not make, based on our knowledge and our priorities,and will be well into the future.