On December 5, 2012, the National Aeronautics and Space Administration (NASA) released new images of Earth from space. These striking images of the planet at night, which NASA dubbed the “Black Marble,” showed a dark Earth dotted unevenly with yellow lights. Cities, sprawling suburbs, and industrial corridors are easily visible and recognizable from space; rural and more remote territories are nearly black. The accompanying feature article posted on NASA’s website that day, “Out of the Blue and Into the Black: New Views of the Earth at Night,” played on Neil Young lyrics from 1979, likely suggesting the historical and cultural milieu of many NASA scientists.1 The timing and title were hardly coincidental. On December 7, 1972—almost exactly forty years earlier—NASA issued its famous Apollo 17 Blue Marble photograph that became an icon of American environmentalism (figure 1).2
Although NASA released a series of images that day, including a global map of artificial light at night that soon circulated through news media and popular scientific publications, its cover story began with City Lights of Africa, Europe, and the Middle East (hereafter, City Lights; figure 2).3 This arresting representation of the nocturnal planet as a hemisphere dramatizes stark contrasts in artificial light at night: brightly illuminated European capitals, the Nile valley, and Middle East oil fields stand out while much of Africa is dark. Just eight lines of text preceded City Lights, making most of the image visible to any visitor to the NASA website.
In this essay, I offer a close reading of City Lights, showing how the image’s colors, features, and layout draw attention to human presence and planetary impact, even at night, evoking growing discourse about the Anthropocene.4 As NASA staff wrote early in their feature article, mapping artificial light at night provides “a global view of the human footprint on the Earth.”5 The image’s framing and characteristics recall the famous Blue Marble photograph, thereby extending environmentalist concerns to the nocturnal planet. Yet a detailed examination of City Lights demonstrates there are also significant differences between the Blue and Black Marbles. Moreover, by dramatizing global inequalities in artificial light at night, City Lights romanticizes darkness with profound implications for Africa and rural regions in the developing world more broadly.
My analysis of City Lights is informed by literatures in environmental history, science and technology studies (STS), and their nexus.6 First, Michelle Murphy’s concept of regimes of (im)perceptibility offers a powerful way to scrutinize City Lights and its making. Murphy teases out how arrangements of discourses, objects, practices, and subject positions work together within a particular discipline or knowledge tradition to shape what is perceptible, knowable, and therefore known—and simultaneously, what is imperceptible, unknowable, and thus unknown.7 In this article, I examine how NASA visualized artificial light at night and made certain knowledge of nighttime lighting literally (im)perceptible. By critically analyzing “the environment” represented in City Lights, it is not only possible but also necessary to consider the image’s implications for both environmentalism and environmental justice. Building on these insights, STS scholars have shown how the framing of a problem shapes how it is understood and addressed.8 Here, I explore what it means to examine images like City Lights through the lens of light pollution, rather than that of lighting poverty. Finally, as the title of this article suggests, William Cronon’s problematization of wilderness in his now-classic essay informs my critical reading of City Lights and darkness more broadly.9 Before naively touting “natural night-sky brightness,” I suggest that we—light-pollution critics, environmentalists, and environmental historians alike—must contemplate the trouble with darkness.10
CITY LIGHTS: THE IMAGE
One of the defining features of City Lights is its visual simplicity. The image lacks the visual busyness, bordering on chaos, of many cartographic representations of Earth or parts thereof. Maps and globes are typically peppered with lines, colors, shading, numbers, and labels that denote various political, topographic, geographic, and other features. In contrast, nothing is explicitly identified in this image. It also has a limited color scheme. Immense oceans are colored midnight blue. Continents with little artificial light at night, like Africa, are dark blue. Blue-tinged clouds offer additional minor variations in shading. The bright yellow-white of artificial light is patchy, unevenly distributed, and comprises a small share of the overall surface area.
This color scheme is marked by both an absence and an amplification of contrast. On the one hand, terrestrial and oceanic Earth are barely differentiated, except in places like western Europe, with its extensive artificial lighting. The planet itself seems to merge with the cosmos, with the notable exception of the bright white arc of sunlight to the west. On the other hand, artificial light pops against the monochromatic blue-black background. Such light particularly stands out given the visual contrast of blue and yellow, colors nearly opposed on the color wheel. Yet according to modern color theory, such colors are perceived as complementary despite their near opposition.11 The resulting harmonization further quiets a seemingly simple, tranquil image.
The juxtaposition of (literal) light and dark, yellow-white and blue-black in City Lights is, in fact, more subtle than some other images of artificial light at night produced by the community of scientists studying this issue. These images employ the full color spectrum to distinguish among lighting levels: from least (blue and green) to midrange (yellow and orange) to most (red and pink).12 Such differentiation makes areas of intensive or extensive light pollution more readily visible by dramatizing the range of artificial light at night and associating red hues with its highest levels.
The frame of City Lights is also important because it bounds and spatially defines Earth in particular ways. City Lights offers a “view from above”—far above—specifically, from space: 824 kilometers (512 miles) above Earth.13 The image also represents the planet as a three-dimensional orb, but it is a close shot of the “whole Earth.”14 The cosmic blackness offers a uniform backdrop to the planet, but little of it is shown, especially if we consider the vast scale of the cosmos. The relative proportion of Earth and cosmos in City Lights contrasts, for example, with other similar, famous images, including Earthrise, from the Apollo 8 mission on Christmas Eve 1968, or even more dramatically, Carl Sagan’s Pale Blue Dot, captured by the Voyager 1 space probe in 1990.
Of course, it is essential to remember that all images are produced, and City Lights is no exception. We cannot mistake image for reality, despite NASA declarations that it offers “a realistic view of the planet.”15 Such assertions of hyperrealism ignore, even obscure, the context and politics of producing images like City Lights. Various choices shape what viewers (can) see.16 In this case, NASA technicians produced City Lights not, as it may appear, from a single photograph taken from space; rather, they compiled, mapped, and colored new satellite data to make the image more like a photograph.
Indeed, City Lights resulted from the launch of the Suomi National Polar-orbiting Partnership satellite in October 2011, which was a joint venture by NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. One of the satellite’s distinct features was a “Visible Infrared Imaging Radiometer Suite” (VIIRS), which both exemplified and accomplished the goal of better nighttime imaging of Earth.17 VIIRS’s “day-night band” was (and still is) particularly effective at acquiring data in conditions of low lighting, such as clouds or night. As NASA stated, the Suomi satellite’s new low-light sensor “can distinguish night lights with six times better spatial resolution and 250 times better resolution of lighting levels.” The Suomi satellite collected data for nine days during April 2012 and thirteen days that October as the satellite passed over any given location on Earth at roughly 1:30 a.m. and 1:30 p.m. local time each day, observing the planet in vertical strips from pole to pole.18 NASA scientists then compiled the data into a composite image of the entire Earth. Next, they mapped Suomi data “over existing Blue Marble imagery of Earth” precisely “to provide a realistic view of the planet.”19 This is partly why NASA’s new Black Marble so closely resembles the older Blue Marble imagery.20 In addition, NASA scientists colored the data—originally black and white—blue and yellow to fit our understanding of what artificial light at night looks like.21 As I discuss later, other decisions the agency made shaped its construction of nocturnal Earth and therefore our understanding of darkness and “the environment” at night. Such image-processing choices, however, received far less attention than the new images of the nighttime planet NASA released that December.
FROM BLUE TO BLACK MARBLE
Why was City Lights featured at the top of NASA’s cover story? I argue that this image—more than the global two-dimensional map NASA produced (figure 3)—evokes the famous Blue Marble photograph visually, rhetorically, and historically.22 The hemispheric representation of Earth, the fact that the planet floats within space, and the relative proportion of Earth and cosmos all conjure this earlier image and thereby foster continuities between them. Moreover, recall that Suomi data were superimposed onto Blue Marble imagery. The Black Marble is therefore not just modeled on Blue Marble imagery, but constituted from it. In addition to these visual similarities, the title of NASA’s cover story, “Out of the Blue and Into the Black,” explicitly links old and new “Marbles.” It establishes the new Black Marble images as the next stage in this planetary imagery—and planetary imaginaries.23 NASA’s announcement in early December deepened these visual and rhetorical connections. The agency released the Suomi-based images just two days shy of the fortieth anniversary of the Blue Marble photograph.
The strong parallelism forged between the 1972 and 2012 images of Earth from space not only reflects but also reinforces NASA’s commitment to environmentalism. As Erik Conway, W. Henry Lambright, and Kim McQuaid have shown, NASA began to reframe the space sciences in environmental terms and articulated an environmental mission in the 1970s and 1980s.24 Its Earth Observatory program features the clever motto “Where every day is Earth Day.” The comparison also hints at NASA’s aspirational vision for its Black Marble imagery and Earth at night. Scholars such as Denis Cosgrove, Finis Dunaway, Sheila Jasanoff, and Neil Maher have argued that the Blue Marble photograph, like Earthrise four years earlier, played a crucial role in modern environmentalism.25 By establishing visual, textual, and historical similarities between the Blue and Black Marble images, NASA seeks to catalyze environmentalism in the twenty-first century. If Earth Day reflected and inspired environmental activism in 1970, perhaps Earth at night can incite a new generation of environmentalists in the early twenty-first century.26 Furthermore, the planetary scale of these images resonates with contemporary discourses about global climate change and the Anthropocene. Overall, NASA constructed smooth, seamless links between its Blue Marble and new Black Marble imagery in its visual and textual narratives.
Nonetheless, amid these purported continuities, NASA’s Suomi imagery mobilizes new sites of environmental concern (nightscapes and nocturnal Earth) and new kinds of environmental issues (light pollution). In fact, there are several important differences between the two images. First, Apollo 17’s Blue Marble is a photograph; NASA’s Black Marble is not. Yet City Lights was made to look more photograph-like by amalgamating data into a singular image of whole Earth, adding realistic coloring and superimposing clouds.
The hemispheric focus of the two images is also different. The entire continent of Africa was more central to the famous Blue Marble photograph. This geographic focus was possible because the photograph was taken from a vantage point south of the equator. Africa’s imposing presence in the image is even more impressive—but perhaps also threatening—given that Apollo 17 astronauts took the Blue Marble photograph on the heels of decolonization.27 In contrast, the Northern and Southern Hemispheres receive equal representation in City Lights. In this sense, Black Marble assumes a neutral observer looking down from a perfect omniscient point exactly above the equator. This position epitomizes Donna Haraway’s so-called god trick and James C. Scott’s high-modernist expert observer.28 As a result of this vantage point, the Middle East is at the center of City Lights. Africa is visible and comprises a large share of the image, but it is nonetheless more marginal than in Blue Marble.
In addition, these images are distinct in their relative representations of dynamism. The Blue Marble photograph suggests Earth in motion. The planet is tilted (unusually so, given the observation point closer to the South Pole) with a vigorous eddy of white swirling clouds suggesting additional layers of movement. Its colors—blue, green, brown, and white—connote life and vibrancy.29 In contrast, the Black Marble, especially as it is shown in City Lights, is a static, somewhat flat image. The Black Marble shows clouds, but they are tinted dark blue, making it difficult to distinguish among land, ocean, and skies. Together, the monochromatic coloring, subtle shading, and lack of obvious movement offer a still snapshot of a nocturnal planet ostensibly asleep. The Black Marble’s flatness, stasis, and hemispheric focus collectively decenter and control Africa. This imagery’s taming of Africa is particularly significant, given the history of conservation and the implications of conserving natural nightscapes there.
DRAMATIZING LIGHT AND DARK
Several choices NASA made in City Lights amplify regional contrasts in artificial light at night. First, NASA’s VIIRS sensor aimed to capture “earthly night lights.”30 Most NASA discourse has focused on “night lights,” “nighttime lights,” or observing Earth at night.31 Such framings leave room for the inclusion of both natural and artificial sources of nighttime lighting. NASA decided, however, to filter out “stray light,” which it has defined as “natural” sources of light. As stated, “auroras, fires, and other stray light have been removed to emphasize the city lights.”32 Thus, although the Suomi satellite captures all light at night, regardless of source, ultimately NASA has included only artificial light at night in its Black Marble imagery.
This decision has had enormous implications, as environmental historians, science studies scholars, environmental humanists, and others know. Filtering out natural sources of light such as fires, volcanoes, and biofluorescence reifies and reproduces the separation of nature and culture. By doing so, NASA has obscured a more complex understanding of light since the development of artificial lighting in the late nineteenth century as a hybrid, natural-cultural, envirotechnical phenomenon.33 Furthermore, the agency actually amplified the difference between light and dark in City Lights by erasing natural lighting. Dark areas became darker because any natural light was removed. As a result, NASA has mapped darkness and light to nature and culture. The parallelism between these terms is especially important, given their cultural meanings in the West that include the Judeo-Christian tradition and the Enlightenment.
Moreover, neither natural nor artificial light is as clear cut as either term implies.34 Fires, for instance, generate natural light. Yet as Stephen Pyne and other environmental historians have demonstrated, fires often result from a complex combination of natural factors such as drought and a given forest’s species composition, and human factors such as fire suppression policies and cigarette use.35 Even individual natural factors such as drought or climate change belie the complex dynamics of natural-cultural processes.36
Artificial light is also more complicated than the term and NASA’s images suggest. Other scientists studying artificial light at night, including those at the Natural Sounds and Night Skies Division of the US National Park Service (NPS), have argued that satellite imagery like NASA’s does not actually capture all artificial light. The Suomi satellite “sees” any light that makes it way through the planet’s atmosphere to space. However, clouds and particles in the atmosphere prevent some artificial light from being visible. More significantly, satellite imagery does not depict the full impact of artificial lighting on localized nightscapes. Clouds and particulates can cause light waves, including artificial light, to bounce back to Earth, thereby magnifying light pollution on a local (or regional) scale. Satellites, then, are effective at making artificial light at night perceptible on large—especially continental and planetary—scales, yet they simultaneously underestimate artificial light at night and its attendant effects on smaller spatial scales. NPS scientists who point out the limits of satellite imagery call their own approach “ground truthing”; they take night-sky brightness measurements from the ground.37 This term suggests an alternative approach to knowing, measuring, and visualizing artificial light at night, albeit one with its own limits. Both natural and artificial light thereby resist tidy categorization.
Another choice NASA made that dramatizes regional disparities in artificial light at night is the spatial focus of City Lights. Given its global data, NASA could have chosen many hemispheric framings of Earth—placing, say, the Americas at the center of the image. Instead, as the full title of City Lights states, this image is centered on “Africa, Europe, and the Middle East.” These spatial parameters consequently maximize regional differences in artificial light at night by including some of the brightest and darkest nightscapes on the entire planet in a single hemispheric frame.38
Making continents’ borders visible has brought these inequalities into sharper relief. Regional differences between Europe and Africa, for instance, would be less perceptible if continental edges merged into the ocean, except in places like Italy, the Nile valley, or the Niger delta, where artificial light at night clearly denotes land and sea. Instead, demarcating the continents—even if done subtly, as City Lights has done through the use of two similar colors—has facilitated the visualization of regional disparities in artificial light at night.
Moreover, each geographic region has been made to look more extreme—either lighter or darker—because of its proximity to and juxtaposition with the other. Africa looks darker because Europe is located almost directly above it, and, as City Lights makes apparent, Europe has both intensive and extensive light pollution. At the same time, Europe looks brighter because it is so close to a large swathe of land with little artificial light at night. The expanses of the Atlantic and Indian Oceans are dark, but the continent of Africa stands out for its relative darkness, especially when compared with other land masses. In short, Africa’s relative lack of nighttime artificial light makes Europe’s light pollution more perceptible—and vice versa.
Artists’ understandings of positive and negative space help us read Africa’s place in this hemispheric representation of artificial light at night. Positive space is the subject of the painting. By definition, negative space is not the subject; it serves as background or backdrop. Yet artists underscore how positive space needs negative space to work. Negative space is complementary to positive space by serving as setting and contrast. Positive and negative spaces are therefore relational and interdependent.39
As the title of City Lights makes clear, artificial light at night is the positive space of the image, and dark areas are the negative space. The color scheme of City Lights magnifies the complementarity of positive and negative space in this image because of the harmony of blue and yellow. The general absence of artificial lighting in some territories is, then, remarkably present. Here, Africa literally appears as, in Henry Stanley’s famous words, “the Dark Continent.”40
Needless to say, although it may appear objectively true that Africa has little artificial light at night, it is still problematic to depict Africa as “the Dark Continent” more than a century after the heyday of European colonialism. After all, Africa was made darker because NASA filtered out natural lighting sources, and it looks darker because of its proximity to Europe. More importantly, contemporary light-pollution scientists and conservationists need to consider Africa’s colonial and postcolonial histories when they describe and justify the protection of “dark skies” in Africa specifically, and the global South more broadly. The mapping of related terms in City Lights—positive space/light/culture/Europe and negative space/darkness/nature/Africa—is deeply unsettling, given racism, imperialism, and development.41 Whatever NASA’s motivation, the geographic focus of City Lights on “Africa, Europe, and the Middle East” is not an innocent choice. It magnifies the technological drama of artificial light at night by selecting the hemispheric slice of the planet with the greatest contrasts.42 By doing so, the juxtaposition of Europe and Africa at night reproduces entrenched dichotomies and risks repeating colonial narratives.
FROM LIGHT POLLUTION TO LIGHTING POVERTY
If we focus on the positive space of City Lights, as NASA intends, this image serves as a map of light pollution. Drawing our attention to brightly lit areas, as City Lights does, simultaneously diverts our attention from darker regions. This means viewers tend to see the problem of light pollution in the urban, industrialized world and ignore the problem of poverty—which explains the relative absence of artificial light at night—in much of the developing world.43 The political stakes of this perspective are even greater because City Lights is not only a scientific visualization; it is also a beautiful image.44 The aestheticization of light pollution in City Lights and many other images of artificial light at night melds the astronomical sublime with the ecological sublime.45 However, focusing on the beauty of these images has serious political implications; concentrating on their aesthetics depoliticizes the causes of light pollution, as well as its absence.46
Shifting one’s perspective and concentrating on the negative space in City Lights therefore offers a quite different reading of the same image. This alternative appraisal instead forefronts lighting poverty: limited or nonexistent access to electricity, including reliable, adequate, clean sources of artificial light.47 Yet this insight—that City Lights says as much about lighting poverty as it does about illuminated nightscapes—is obscured by the image’s title. This other reading of Suomi satellite images of Earth at night, and of City Lights specifically, thus offers a radically different message focused on vast, persistent global inequalities as manifested through artificial light at night.
Light-pollution scientists and activists critique artificial light at night and value “natural” night skies. Organizations like the International Dark-Sky Association have tried, however, to combat the idea that the only solution to light pollution is to turn off all the lights and stumble around in the dark.48 Instead, they and others promote “the four Rs”: “lighting in the right place, at the right time, at the right level, in the right spectrum.”49 Although many scientists and activists make careful arguments in defense of dark skies, at times they romanticize them, making sweeping statements about the transhistorical, transcultural value of nightscapes. Consider one typical statement: “We are losing the mesmerizing view of the deep night sky that has fascinated all preceding civilizations.”50 In general, too few in the light-pollution science and conservation communities have paid adequate attention to vital social justice issues including the benefits of artificial lighting and the ways in which darkness can index low standards of living, even dire poverty.51
Furthermore, images that make excessive artificial light at night throughout much of the urban, industrial world perceptible, as City Lights does, help justify the protection of regions with remaining natural nightscapes. Most of these places are in rural parts of the developing world. Indeed, Africa has some of the largest contiguous land mass with natural night-sky brightness. Although well intentioned, such efforts to conserve natural night skies may end up reproducing (neo)colonial forms of conservation that place landscapes of tourism, leisure, and aesthetics for wealthy outsiders at odds with ensuring local livelihood and improving basic standards of living.
As environmental historians know, this is an old story.52 Critiques of these very arguments have pushed environmentalists, natural resource managers, and conservation scientists over the past two decades to develop alternative conservation strategies, such as working landscapes, land-sharing/land-sparing regimes, and community conservation, as well as new rationales for conserving nonhuman nature including ecosystem services. Such approaches have attempted to promote both environmental protection and human welfare, and they involve local communities in conservation. However, newer discourses about artificial light at night tend to reproduce older conservation rhetoric, even though concerns about light pollution have increased precisely at the moment when these new, more livelihood-centered conservation strategies have been developed and implemented. Reframing City Lights as a map of light pollution and lighting poverty would be one small, but positive step toward avoiding neocolonial approaches to the conservation of natural night-sky brightness.
CONCLUSION: THE TROUBLE WITH DARKNESS
In 1995, William Cronon published his now-classic essay, “The Trouble with Wilderness,” that challenged many common understandings of wilderness as a place, a concept, and an ideal.53 My concern is that many of the problematic assumptions about wilderness that Cronon identified and criticized over two decades ago—the separation of nature and culture, the idealization of landscapes of leisure, the failure to address fundamental questions of livelihood, and the argument that any human use of nonhuman nature is abuse—shape contemporary discourse and activism around the emergent issue of light pollution.54 Given that scientists, conservation groups, and environmentalists since the 1970s, and especially over the past decade, have become increasingly concerned about the ecological and human health effects of artificial light at night, it is likely that nightscapes are a new frontier in twenty-first century conservation, a metaphor I use with considerable trepidation given its entanglement in colonial, racist, and patriarchal histories.55
My analysis of City Lights of Africa, Europe, and the Middle East demonstrates that we need more thoughtful, reflective strategies that benefit from the lessons of environmental history. Dark night skies, or “natural night-sky brightness,” should be recognized, celebrated, and ultimately protected.56 But we should do so in a way that advances both environmentalism and social justice. Otherwise, we have learned little from the history of conservation over the past 150 years.
Sara B. Pritchardis associate professor of science and technology studies at Cornell University. She is the author of Confluence: The Nature of Technology and the Remaking of the Rhône (Cambridge: Harvard University Press, 2011) and coeditor (with Dolly Jørgensen and Finn Arne Jørgensen) of New Natures: Joining Environmental History with Science and Technology Studies (Pittsburgh: University of Pittsburgh Press, 2013). Her current research examines the history and politics of light-pollution science. This work has been supported by grants from the National Science Foundation’s Program in Science, Technology, and Society (Grant No. 1555767), as well as Cornell’s Society for the Humanities and the Mario Einaudi Center for International Studies.
I thank Ian Jared Miller and Paul Warde for inviting me to participate in the “Carbon and Its Discontents: The Futures of Energy History” workshop at the Joint Center for History and Economics at Harvard University in May 2015, where I actually presented a different essay. That workshop nonetheless served as the impetus for bringing this idea to fruition. I am grateful to Lisa Brady and Finis Dunaway, editors of Environmental History and its “Gallery” section, respectively, for their encouragement. I thank Neil Maher for his insightful feedback during the peer review process. Because academia is a small world, we ended up outing ourselves as author and critic. I presented an early version of this article to graduate students in the History of Architecture at Cornell University, who offered valuable comments; thanks to Margot Lystra for inviting me to present to that bright community. It is always a pleasure to acknowledge the members of my interdisciplinary faculty writing group—María Fernández, Durba Ghosh, TJ Hinrichs, Rachel Prentice, Marina Welker, and Wendy Wolford—for their brilliant insights, constructive feedback, and sense of humor. I also thank Shoshana Deutsh, Jenny Goldstein, Julie Livingston, Laura Jane Martin, and Fernando Rodriguez for their contributions at other stages of the revision process. My amazing research assistant, Erin McLaughlin, helped with the images; her work is supported by the National Science Foundation’s Program in Science, Technology, and Society under Grant No. 1555767. Finally, I thank Robert Kulik for his editorial assistance—again.