An Art Historian Reflects on the Beauty and Significance of Hubble Telescope Imagery

In a gorgeously-illustrated and thoughtful new academic book, Picturing the Cosmos: Hubble Telescope Images and the Astronomical Sublime, Stanford art historian Elizabeth A. Kessler analyzes space imagery in the context of centuries of landscape art and photography. She shows us stunning parallels between Romantic landscape paintings that people once created of the "frontier" in the Americas, and the images we produce using space robots and orbital telescopes. What emerges is an analysis of space pictures unlike anything you've ever read before. These aren't just scientifically accurate reproductions of outer space, but works of art. We've got an excerpt from the book, from the introduction where Kessler introduces her central thesis.

Introduction: Astronomy's Romantic Landscapes

Hubble Images and Aesthetics

A dark cloud against a background of orange and blue reaches upward, stretching nearly to the top of the frame that contains it. Brightly backlit at its top and outlined throughout with a soft glow, the majesty and grace of the sinuous shape claim the viewer's attention (Figure 1, below). But the closer one looks, the more difficult it becomes to classify what is pictured. Because of its wispy outline and top-heavy proportions, it appears that the form must be composed of something airy, something gaseous and insubstantial; however, its elongated profile resembles none of the clouds seen above the earth, and its blackness surpasses that of even the most threatening storm. Its color and assertive vertical orientation instead suggest a gravity-defying geological formation carved into a twisting pillar by unknown forces and silhouetted against a bright sky. The object almost oscillates before the viewer: cloud and landscape, familiar and alien.

The image is one of the many compelling views of the cosmos credited to the Hubble Space Telescope since its launch in April 1990. The National Aeronautics and Space Administration (NASA) and the Space Telescope Science Institute (STScI), the research center that manages the instrument, released the image of the Eagle Nebula, along with one of the Whirlpool Galaxy (Figure 2, at the top), to celebrate the orbiting telescope's fifteenth anniversary in April 2005.1 The view of the Whirlpool is less ambiguous than that of the Eagle; its distinctive spiral shape is iconic, the recognizable sign of a star system akin to the Milky Way. It is, however, no less powerful an image than the representation of the Eagle Nebula. The dynamic whirl pulls the eye along pathways dotted by red stars into the galaxy's brilliant yellow center. The subtle blues of its arms contrast with the warmer yellows and reds of the stars. As with the Eagle Nebula, the celestial object nearly fills the frame, conveying a sense of its vast size and scale. And for both images, the most highly resolved versions reveal incredible, even overwhelming, levels of detail. The glowing regions along the spiral arms become individual light sources. Each dot of light, even those almost too faint to discern in an image of lesser quality, gains color, a degree of intensity, and sometimes even shape.

An Art Historian Reflects on the Beauty and Significance of Hubble Telescope Imagery

This book takes Hubble images like these as its subject: their appearance, their production, and their position within the history of scientific and artistic representations. From its orbit above our globe, the Hubble Space Telescope has provided a revolutionary view of the cosmos. Freed from the obscuring atmosphere of the earth, the instrument has allowed astronomers to observe with new clarity, thereby enabling an improvement in seeing that is often compared to Galileo's first use of a telescope in the seventeenth century. Because the Hubble holds a seminal place within contemporary astronomy and its images have circulated widely-to near-universal acclaim-its views of the cosmos have become models for images delivered from other telescopes, including those produced in the service of science at world-class observatories as well as those taken by amateurs with backyard telescopes. Hubble images have also shaped depictions of the universe in popular culture, and it is common in science fiction films, TV shows, and video games to see spaceships fly through Hubble-inspired scenery.

In the more than twenty years since NASA released the first blurry, black-and-white Hubble image, astronomers have developed representational conventions and an aesthetic style, and the archive of Hubble images demonstrates that scientists have come to favor saturated colors, high contrast, and rich detail as well as majestic compositions and dramatic lighting. The vividly colored, exquisitely detailed, and brilliantly lit Hubble Space Telescope images now define how we visualize the cosmos. They do not look like older photographs of the stars, nor are they anything like what can be seen in the sky on a dark night. Yet they appear to present the universe as one might see it, thus previewing what we imagine space explorers and tourists may experience when manned space travel extends humanity's reach beyond the earth's orbit. Improved technology, a telescope orbiting high above the earth's atmosphere and equipped with sensitive digital cameras, can seem like an adequate explanation for the brilliant hues and sharp resolution. But there is more behind the images than just the workings of advanced instruments. The appearance of the Hubble images depends on the careful choices of astronomers who assigned colors, adjusted contrast, and composed the images. Although attentive to the data that lie behind the images, through their decisions astronomers encourage a particular way of seeing the cosmos.

As with the Eagle Nebula, many of the Hubble images bear a striking resemblance to earthly geological and meteorological formations, especially as depicted in Romantic landscapes of the American West. In the late nineteenth century, the painters Thomas Moran and Albert Bierstadt as well as the photographers William Henry Jackson, Timothy O'Sullivan, and others portrayed the awe-inspiring and unfamiliar western scenery in the visual language of the sublime. The formal similarities between these two sets of pictures situate the Hubble images within a visual tradition, and the reference to the sublime also has philosophical relevance. As defined by Edmund Burke and Immanuel Kant, the sublime describes an extreme aesthetic experience, one that threatens to overwhelm even as it affirms humanity's potential. For Kant, the sublime arises out of a tension between the senses and reason, and each faculty must be engaged to experience such an intense response. Through a reprisal of Romantic tropes, the Hubble images once again invoke the sublime and they encourage the viewer to experience the cosmos visually and rationally, to see the universe as simultaneously beyond humanity's grasp and within reach of our systems of knowledge. The tension that begins with the appearance of the Hubble images extends to the relationship between the images and the celestial objects they represent; their reliance on digital data and imaging, which brings together numeric and pictorial representations; and the symbolic significance of the landscape reference with its evocation of the frontier. By repeatedly making use of this tension, a fundamental attribute of the sublime experience, the Hubble images make claims not only about what we know of the cosmos but how we gain knowledge and insights.

Typically, interest in a scientific mission lasts for only a brief period-the duration of a mission or a few weeks of excitement after a new discovery-but decades after the telescope's launch the Hubble images still made headlines and circulated widely online and in print. They achieved an almost unparalleled popularity within the history of astronomical images, even within the history of all scientific images. Many of the best-known Hubble images were made in an effort to reach those who are not scientists, and those involved with their production and distribution, from astronomers to public relations officials at STScI to administrators at NASA, acknowledged that they hoped the eye-catching images would encourage continued financial support for the Hubble Space Telescope, NASA, astronomy, and even scientific research more generally. As a result, some dismiss the aesthetically developed Hubble images and their evocation of the sublime as little more than hype and visual hyperbole, and consider them nothing more than crass attempts to curry public favor.

Aesthetics can seem secondary at best and often unnecessary to the scientific project. If science strives to master with precision and exactitude the physical processes at work in the universe, if it ultimately seeks to enhance the human condition through improving and extending life, aesthetics can seem a messy distraction from its larger goals. At times, astronomers have argued against dedicating significant resources to making attractive pictures, suggesting that images might be valuable public relations tools, but data-unambiguous numeric values and measurements that could be logically analyzed, compared with other data, and lead to carefully reasoned conclusions-were the intended output of the Hubble Space Telescope. If "pretty pictures," a phrase often used by astronomers, do not forward the quest of science in the purest sense, if they cannot be used as sufficient evidence to make claims about the physical makeup of the cosmos, the production of such images was little better than a diversion.

Those who study the visual culture of science have also entered into the debates around scientific images. The art historian James Elkins, who has written extensively on the relationship between art and science, has been emphatic in his dismissal of scientific images made for public display, seeing such pictures as contributing to what he calls "astronomy's bad reputation" for producing flashy but scientifically uninteresting images.2 Elkins rejects images made for display because he sees them as a distraction from what he considers to be far more interesting astronomical images, namely those that scientists use only for the acquisition of knowledge. Elkins is correct that scholars of visual culture often ignore the blurry, black-and white-images that show a distant celestial object in only a few pixels. But he too quickly pushes aside the colorful views that reach a larger audience and too strongly judges them as lacking in value. To regard them as little more than overwrought marketing material ignores the depths of their connections to the practice of science as well as how profoundly the images shape our cultural imagination.

The astronomers who develop Hubble images attempt to balance the often contradictory demands and interests of an audience that ranges from fellow astronomers to schoolchildren. As they craft the images, translating sometimes invisible attributes of the data into visible form, they strive to make the images scientifically valid and aesthetically compelling.3 The resulting Hubble images have served multiple functions: they document and record data; aid scientists in their effort to understand their observations; influence decisions about support for science; and inspire aesthetic responses from a variety of different audiences. To understand the complexity of these images requires a careful study of the visual culture of astronomy, one that considers the decisions astronomers make when composing the scenes and choosing contrast and color, the institutions and groups involved in the making of images, and the relationship of the images to the culture that surrounds them.

The Eagle Nebula and the Whirlpool Galaxy images were crafted by members of the Hubble Heritage Project, a group of astronomers and image processing specialists at STScI that took as its purpose the development of aesthetically attractive images. Since its formation in 1997, the Heritage Project has released a new image almost every month, and its work has resulted in an archive of vividly colored and dramatically detailed views of nebulae, galaxies, and other celestial phenomena. The collection supplements and expands the body of images astronomers produced as part of their research programs or those developed for NASA press releases. As a result, the Heritage Project has played a significant role in defining how Hubble images "should" look. And as the name suggests, the group also looked toward the future by shaping not only the perception of the Hubble Space Telescope and the universe for viewers today but also how they will be seen by later generations.

The Heritage Project's mission is in large measure educational, and the group documented its methods for crafting images in publications that reach both those within the astronomical community and those outside of it. Such accounts tell part of the story, often focusing closely on how to make an image. To gain greater insight into what motivates their choices and what they want the images to communicate, I conducted oral histories with several astronomers and image specialists (a title for those who specialize in crafting data into images) involved with the project as well as astronomers who have had a significant role in shaping the appearance and distribution of Hubble images. These interviews revealed the profound commitment of astronomers to conveying the awe they feel when observing the cosmos. Although not a programmatic choice, the reference to the sublime landscape so evident in the Hubble images ensures that we too view the distant reaches of the universe with a sense of wonder and a sense of familiarity, which suggests that we know how to explore these places.

The members of the Heritage Project are the characters who have the leading roles in the story of the Hubble images, but others play significant parts: administrators and scientists at NASA, the engineers who built and designed the instruments aboard the telescope, the larger community of astronomers who support images (or at times reject them). The status of the Hubble Space Telescope, the promise that it would improve our view of the cosmos by several orders of magnitude, ensured that its history was carefully documented. Many of those who participated in its early development were interviewed multiple times by the historian Robert W. Smith, and returning to these older oral histories demonstrates the depth and complexity of astronomy's relationship to images.4 The history of the Hubble Space Telescope remains a touchstone throughout this book, and it will receive the most attention when it shapes the images or aids in interpreting them. Other sources offer more complete discussions of the instrument's history. Smith ably documents the telescope's planning and construction within the institution of NASA, and Robert Zimmerman's The Universe in a Mirror offers an extension of that history through the present. Neither author ignores images, but they do not focus extensively on them. This book, on the other hand, is very much about the Hubble images.

Astronomy often serves as the poster child for science by displaying the wonder of exploration and discovery in a nearly visceral manner and without the ethical conflicts that accompany scientific advances in other fields, such as genetics. In many ways, astronomy is about the pleasure of looking. And the engagement of scientists with ways of seeing and presenting the universe testifies to the essential place of aesthetics within any attempt to comprehend the cosmos, understood in the broadest sense of the term as an ordered and harmonious system. To return to Elkins's quibble with scientific images made for an aesthetic purpose, he does acknowledge and accept the possibility that they have led scientists to ask new questions and explore different avenues of research.5 He seems, however, to want to rely primarily on scientists' accounts of how they use images. Such descriptions are of great value; my choice to conduct oral history interviews was motivated by a desire to better understand how astronomers think about their relationship to images. But it is not sufficient to rely solely on these first-person accounts.

Astronomers may not always be fully aware of how profoundly images shape their thinking. The hallways of observatories and university astronomy departments are filled with brightly colored images made from Hubble data as well as other sources. The prominence of images attests not only to their importance within the discipline but also suggests that they have an inescapable influence on how astronomers imagine the cosmos. No matter what astronomers may do at their desks with numbers and calculations, the conversations with colleagues about their research take place against a backdrop of dramatic views. It seems inevitable that such representations of the cosmos filter back into their approach to the data, to the questions they ask, to the interpretations they posit.

Similarly, the colorful views of the cosmos have shaped how those outside of astronomy imagine the universe. Perhaps more significantly, it is often through the wider circulation of images that one finds an exploration of the cultural implications of newly acquired knowledge and understanding.6 The images made to illustrate evolution are one such case, as the historian of science Constance Clark has shown in her study of the evolution debates in the United Sates in the 1920s. Beginning with Charles Darwin's example in On the Origin of Species, tree diagrams of various sorts were an important means to communicate the taxonomic relationship between living things. Scientists read them according to the conventions established within biology. In one typical textbook illustration that featured in the Scopes trial, humans were not listed separately but were instead included as part of a small circle labeled "mammals." For scientists, neither the failure to call out the human species nor the small size of the circle was problematic because it accurately represented the place of humans within the accepted classification system as well as the comparatively small number of mammal species. While not unaware of the political and religious implications of evolutionary theory, they understood the images as "maintain[ing] silence on questions of religious or political significance." Within the context of the Scopes trial, the very same image gained a different valence. As Clark writes, "For scientists this illustration was a version of a familiar branching diagram depicting natural relationships. From [William Jennings] Bryan's point of view it seemed to mock traditional verities about human significance. It was the human place in nature that was at stake."7

An Art Historian Reflects on the Beauty and Significance of Hubble Telescope Imagery

This example helps to demonstrate that focusing solely on how scientists use images and ignoring their efforts to communicate with a larger audience can overlook what's at stake in the acquisition of new knowledge. Attending to the images that move beyond the laboratory or a scientist's computer screen makes evident the trenchant questions and issues raised through the pursuit of scientific understanding. And in the case of the Hubble images, what could be more significant than how we imagine the universe and our place within it?

For the Hubble images, a reference to a familiar visual iconography, that of nineteenth-century landscape of the American West, threads through efforts to reach a broad audience. The comparison of Hubble images and Romantic landscapes begins with their shared features, similarities in appearance that link two sets of images made more than a century apart. Historically, scholars have often used formal resemblance, an interest in patterns, or a concern with structure as bridges between art and science.8 And although carrying different names-morphological versus formal analysis-the ability to look closely and carefully at representations is an important skill in both art history and astronomy. The purpose of such visual examination differs in each field, of course, with astronomers interested in understanding the physical processes at work in a galaxy or nebula and art historians intent on understanding the image itself: how it was made, how it encourages a viewer to respond, and how it interacts with other images and the culture more broadly.

As the relationship to nineteenth-century landscapes and paintings demonstrates, astronomers did not create their views of nebulae, galaxies, and star fields in a vacuum of objectivity. The social conditions that surround the creation of scientific images make evident some of what motivates this relationship between two sets of historically distant pictures. A rich and ideologically complex culture informed scientists' efforts to translate data into images. Rather than creating something entirely new, astronomers, who were working in a period of great technological change as digital imaging transformed the production and distribution of images, extended an existing mode of visualization and representation, one associated with exploration, to a new phase of discovery. The mythos of the American frontier functioned as the framework through which a new frontier was seen.

Although closely studied, scientific images are not typically scrutinized in the same manner as those produced for artistic purposes. The Hubble images, though, deserve just this kind of attention. Not only do those made for public consumption make aesthetic claims, they are part of what W. J. T. Mitchell has called "a visual turn," a cultural fascination with and an embrace of images that fuel our visually saturated world.9 Despite their omnipresence, our love of images is accompanied by a pervasive uncertainty about their validity and trustworthiness.10 This ambivalence surrounds the Hubble images, as I will explore in future chapters. It is also made manifest in our failure to give images the attention they are due: to recognize the power that they hold; to acknowledge their ability to move, to persuade, to inform, to inspire; and to interrogate them fully, to excavate the sources of their meanings and, especially in the case of the Hubble images, the reasons behind their popularity. In contrast to this uncertainty, visual evidence is central to this book. The images do not simply illustrate; they are the very material through which I make arguments about science and aesthetics, about the history of the Hubble Space Telescope, and about its significance in American culture at the end of the twentieth century and the beginning of the twenty-first.

To give the images their due, to understand them fully, requires a broad, interdisciplinary study that synthesizes the history of science and technology, philosophy, and art history. As might be expected from such an approach, the result is a series of nested and sometimes tangled arguments that draws on disciplines sometimes seen as in opposition to one another. And yet, this tension is exactly what Kant finds productive about the sublime. Multiple arguments thread through the chapters in this book, which are linked together through their relevance for understanding the Hubble images and, perhaps even more significantly, for understanding how late twentieth-century Americans saw the universe and their place within it.

Celebrating an Anniversary: The Eagle Nebula and the Whirlpool Galaxy

In many ways, the two images that I discussed in the opening paragraphs above demonstrate the necessity of using multiple lenses in order to fully understand the Hubble images. Although captivating for their appearance alone, the views of the Eagle Nebula and Whirlpool Galaxy are more than impressive visualizations of scientific observations. They exemplify the ways in which the Hubble images circulate and function in the world.

The Eagle and Whirlpool images also resonate with the history of the Hubble Space Telescope and the longer history of astronomical observing. An earlier image of the Eagle Nebula, often called the Pillars of Creation, was released nearly ten years before the anniversary image. It focuses on a different region of the nebula that features a set of ambiguous columns also resembling both clouds and landscape formations. Perhaps more than any other Hubble image, that first dramatic view of the Eagle Nebula revived the telescope's reputation after the devastating discovery of its flawed optics, and it remains widely admired.11 Although observed with a different camera and exhibiting subtle visual differences, the later Hubble image of the Eagle Nebula pays homage to the first.

The view of the Whirlpool Galaxy looks further back into the history of astronomy and alludes to images that recorded the discovery of the distinctive shape of galaxies. In the 1840s, Lord Rosse, a wealthy amateur astronomer and engineer, built a giant six-foot telescope, aptly dubbed the Leviathan, on his Irish estate. The largest instrument of its day, the audacious structure was a landmark in a long tradition of building ever more impressive instruments to collect light from the distant reaches of the universe. The cloudy nights of Ireland limited the use of the Leviathan, but Rosse and his assistants made one extremely valuable discovery when they observed that the glowing cloud known as M51 had a spiral shape, a form that they also found in some other nebulae. Drawings and engravings of the newly dubbed "Great Spiral" circulated widely, and the revised perception of the universe made it possible for astronomers to imagine that the Milky Way did not comprise the entire universe but was one among many similar star systems.12 By revisiting the object that was pivotal in advancing science's notion of the cosmos, the Hubble's image of the Whirlpool underlines the value of building ever better instruments for observing. The engineering feats of launching and repeatedly returning to an orbiting telescope make the Hubble Space Telescope a contemporary example of Rosse's audacity with even greater potential to forward scientific understanding.

As much as the Hubble's anniversary images point to the past, at the time of their release they also looked ahead to the future of the orbiting observatory. In January 2004, in response to the space shuttle Columbia accident of the preceding year, NASA canceled all future repair missions to the Hubble Space Telescope. The possibility of returning to the observatory for periodic servicing missions was one of its key features. During four previous visits, astronauts had replaced and repaired cameras, spectrographs, and other instruments, including critical and highly temperamental gyroscopes. The Hubble relies on three gyroscopes to guide its pointing mechanism and to remain stable in its orbit. At the time of NASA's announcement, it had only one gyroscope in reserve because two of the six on board had malfunctioned.13 Canceling the repair mission meant additional failures would render the Hubble useless, transforming it into just another expensive piece of space junk. The scientific community and, more remarkably, a great number of people outside of the community responded immediately and passionately to NASA's decision. Online petitions, newspaper editorials, and letters to NASA argued that the instrument remained a valuable scientific tool and one that NASA should not abandon. With all the public support for the Hubble, it is not surprising that the campaign to reinstate a final Hubble servicing mission succeeded, and a crew of space shuttle astronauts visited the orbiting telescope for the last time in May 2009.

The Eagle Nebula and Whirlpool Galaxy images, however, were planned and crafted when the Hubble's future was uncertain. As such they not only represented two well-known celestial phenomena but also made a plea for the continued support of the instrument by displaying its capabilities in brilliant color and exquisite detail. Most people without advanced degrees in astronomy are hard-pressed to identify exactly how the Hubble Space Telescope has changed and enhanced humanity's understanding of the cosmos. They have, however, seen many examples of the Hubble's dramatic pictures, images that NASA showcases on its Web sites and that also appear on calendars and coffee mugs, album covers and art museum walls. Such pictures serve as visible evidence of the Hubble's success. More than any notion of what astronomers do with the Hubble's data, the stunning images account for the public's support and affection for the telescope.

When releasing the Eagle Nebula and Whirlpool Galaxy observations, astronomers, image specialists, and the STScI press office went to exceptional lengths to reach different audiences. New images and announcements of scientific discoveries are regularly posted by STScI and NASA on their Web sites. For the anniversary images, the STScI press office also distributed more than one hundred large prints, four feet by six feet for the Whirlpool Galaxy and three feet by six feet for the Eagle Nebula, to planetariums and science museums throughout the United States.14 These institutions already exhibited numerous Hubble images, but such large examples display the observations to their best effect. Not only does the size emphasize the immensity of the subject matter but it also makes visible fine details not readily apparent in a smaller image or on a computer screen.

In anticipation of any questions that might be raised about using an oversubscribed instrument with a limited lifespan to make pictures for museum walls, the data for the Whirlpool Galaxy were also released in a format that made it readily usable by researchers. Because of its large size and relative proximity to the earth, observing the entire galaxy required six separate pointings of the telescope, and at each pointing several observations were made with four different filters. The total data set included ninety-six distinct exposures that were pieced together to create the image. Typically, astronomers must do the work of generating a composite for any observations they oversee. By providing the processed data, STScI saved scientists the time and effort they would need to expend before they could begin to analyze the data, to say nothing of the time put into submitting a proposal to use the Hubble. As well as making the task of scientists easier, STScI invited them to publish research papers on the Whirlpool Galaxy.15 With the public release of the dramatic view, the invitation was initially issued as a remarkably resolved and dramatic image that promised data to match.

The existence of these distinct modes of representing the Whirlpool Galaxy points toward a fundamental duality within every Hubble image, even the prettiest ones. Each image is expressed first as data and then translated into pictorial form. Hubble images are mediated several times over. Their appearance depends on the advanced optics of the telescope and its sensitive digital detectors, computer software programs that pictorially render data, and the human operators who use them thereby adding their aesthetics and scientific sensibilities. Each layer of mediation raises important questions about how these images represent the cosmos.

Neither the Eagle Nebula nor the Whirlpool Galaxy images exactly mirror the celestial objects they depict, and the images could look differently than they do. The sensitive digital cameras aboard the telescope numerically record subtle differences in light intensity that are too fine for the human eye to discern. The cameras also register light beyond the visible range, extending into ultraviolet and near-infrared. By using special filters the telescope collects different wavelengths of light, in effect recording the presence of certain colors but always monochromatically. In their rawest pictorial form, Hubble images are black and white, often lacking in clear detail, and covered in white streaks (the traces of high-energy rays bombarding the telescope in its orbit). For large objects, as is the case for the Whirlpool Galaxy, a single image shows only a small portion of the larger whole. To produce the highly polished images for which the Hubble is famous, astronomers must make a series of decisions that combine scientific interests with aesthetic concerns.

A great deal rests on the appearance of the Hubble images. The Eagle Nebula and Whirlpool Galaxy celebrated the successes of the Hubble Space Telescope as well as anticipated its possible demise, and the two images illustrate in concentrated fashion the diverse threads that can be teased out of the appearance of Hubble images. Through their appearance, they evoke an experience of the sublime as they allude to the landscapes of the American West. They also engage with the history of astronomy and of observing the cosmos by looking back to past observations of these objects. They participate in debates about how best to observe and represent the universe, commenting on and ultimately influencing NASA's decisions about their very means of production. In the chapters that follow I will take up these issues, considering not only specific Hubble images but also how the attributes exhibited across the archive
of Hubble images refer to practices of observing the heavens, comment on the place of images within science, and convey a certain notion of the universe.

In the end, the Hubble images not only look like the earthly landscape, they also reflect the complexity of scientific exploration. The greatest discoveries come from inviting reason and the senses, the rational mind and the aesthetic response, to ignite and affirm each other.

Astronomy's Romantic Landscapes

Over the course of four chapters, I analyze the cultural and social significance of the Hubble images. The first chapter begins by addressing their relationship to older aesthetic traditions, namely the sublime and its expression in nineteenth-century views of the American West by artists such as Albert Bierstadt, Thomas Moran, Timothy O'Sullivan, and William Henry Jackson. Through a series of comparisons to the older images, the visual similarities between them are dramatically illustrated. The press releases that accompanied many Hubble images make explicit references to landscapes, and interviews with astronomers demonstrate that they appreciated and encouraged the association. Through these visual allusions, Hubble images reprise the relationship identified as fundamental to the experience of the sublime by both Edmund Burke and Immanuel Kant. By looking at the cosmos, one could grasp the infinite as well as the insignificance of humanity in relationship to such immensity. Yet, at least for Kant, the sublime affirms the potential of the human mind because it demonstrates the capacity of the human faculties to conceive ideas far beyond humanity's perceptual limitations. The Hubble images repeatedly play with this unsettling formulation by simultaneously challenging and championing the power of humans.

Although Hubble images now receive universal praise, attitudes toward colorful, carefully composed astronomical images for a broad audience have a complex history. Astronomers frequently vacillated between embracing such images and questioning their value. In the second chapter I will explore this ambivalence toward visual representations by tracing the history of the Hubble Space Telescope from its earliest planning stages through the formation of the Hubble Heritage Project in 1997. Although some astronomers had dismissed the telescope's images as "pretty pictures" useful mainly for promotion, the enthusiastic response to the Eagle Nebula and its scientific value required critics to reconsider. A group of astronomers at the Space Telescope Science Institute responded by forming the Hubble Heritage Project. Their efforts helped to ensure both a steady stream of images and a consistent visual representation of the cosmos. The results also testify to the critical place of aesthetics in scientific discourse.

In the third chapter I focus on the crafting of Hubble images, a process of translating digital data into legible images. The Hubble Space Telescope's launch and its early years of operation coincided with a period of transition within the history of astronomical imaging as more observatories adopted digital detectors. Hubble images document how institutions and individuals responded to the introduction of a novel medium by developing and codifying new approaches to light, color, and composition. When producing images, astronomers must determine how best to translate invisible attributes into visible form and ensure that the results are both aesthetically appealing and scientifically valid. Neither the data nor the image can completely represent the objects that populate the cosmos, and it may be the movement between the two modes that enables astronomers to gain the greatest insight.

After examining the appearance of the Hubble images, their history and reception, and their mode of production in preceding chapters, in the fourth chapter I take up how and why the Western landscape serves as such a compelling model for the Hubble images. While the first chapter focused on the aesthetic value of the landscape, the last one considers the historical, metaphorical, and phenomenological implications of the resemblance. Many of the nineteenth-century paintings and photographs were made in the service of science, in particular the government-sponsored surveys of the Western Territories. The men who made and circulated western views had concerns that closely mirror those of the astronomers who crafted the Hubble images, and the similarities make clear the depth of the relationship between the two sets of images. Starting at the end of the nineteenth century, astronomers also acted as explorers and pioneers as they established observatories on remote mountaintops. The Hubble images carry with them the memory of late-night observing runs amid the sublime mountain landscapes. Finally, it is through the evocation of the frontier, a complex and contested notion, that the Hubble images introduce a final paradox: although the sublimity of the cosmos may threaten to overwhelm our imaginations, through the powers of wonder and reason we can come to know and understand it.

NOTES

1. "Hubble Celebrates 15th Anniversary with Spectacular New Images," HubbleSite, http://hubblesite.org/newscenter/archive/releases/2005/2005/12/.

2. Elkins, Six Stories at the Edge of Representation, 87. Elkins also discusses the relationship between art and science in The Domain of Images and Visual Practices across the University.

3. For a compelling study of another case of astronomical images that must balance similar demands, see Vertesi, "Seeing Like a Rover."

4. These older oral histories are part of the Space Telescope History Project at the Smithsonian National Air and Space Museum, and are archived at the museum. For a catalogue, see "Oral History on Space, Science, and Technology," National Air and Space Museum, http://www.nasm.si.edu/research/dsh/ohp-introduction.html. They also form the basis for Smith's detailed history of the Hubble Space Telescope's early years. See Smith, The Space Telescope.

5. This is an argument frequently made by the science photographer Felice Frankel. See Domain of Images, 46–48, for Elkins's response to it. For Frankel's work, see On the Surface of Things and Envisioning Science.

6. On the constitutive place of both art and science in culture, see Jones and Galison, Picturing Science, Producing Art.

7. Clark, God-or Gorilla, 133.

8. For an overview of the literature on the interdisciplinary conversation, see Henderson, "Editor's Introduction: I. Writing Modern Art and Science-An Overview; II. Cubism, Futurism, and Ether Physics in the Early Twentieth Century."

9. See Mitchell, "Showing Seeing."

10. On this question, see Jay, Downcast Eyes; Stafford, Good Looking; and Latour and Weibel, eds., Iconoclash.

11. I discuss the optical problems that surfaced soon after the Hubble's launch as well as the story of the Pillars of Creation in the second chapter.

12. More than a century before Lord Rosse made his observations, Immanuel Kant proposed an "island theory" of the universe. Kant was a philosopher though, not an observer, and astronomers gave little credence to his theory. Until Rosse's Leviathan, observations by astronomers provided no support for what is now the accepted view of the universe: a vast number of galaxies scattered throughout the cosmos.

13. One backup might seem like more than enough, but NASA had recurring problems with the Hubble's gyroscopes. Astronauts had replaced them on previous missions, and gyroscope failures had already put the telescope into "safe mode," a state that uses two gyroscopes to keep the telescope in orbit but does not allow for observing, several times throughout its history, including in the months after the final mission's cancelation. Faced with the possible loss of gyroscopes and no repair mission, in 2005 engineers developed new ways to operate the telescope that only relied on two gyroscopes. For two years they used this method as a safe, but inefficient, way of guiding the telescope.

14. The circulation of the Eagle Nebula and the Whirlpool Galaxy images speak to tensions within NASA regarding the decision to cancel the space shuttle mission. Many within the organization disagreed with the choice. It also illustrates the nature of the relationship between STScI and NASA. The functioning of STScI is that of a contractor, one of many that NASA uses, but its primary business is the Hubble Space Telescope and the James Webb Telescope, scheduled for launch in 2018. When the Hubble was threatened, STScI could not act independently to service it, but it could be at least a little rebellious.

15. Several scientists have taken up the opportunity, and the Hubble Space Telescope Data Archive maintains a list of papers based on it. See "HST/ACS Mosaic of M51: HST Proposal 10452," Multimission Archive at STScI (MAST), http://archive.stsci.edu/proposal_search.php?mission=hst&id=10452.

This excerpt (c) Elizabeth A. Kessler, and reproduced with permission from University of Minnesota Press.