Imagine standing in a dark field on a cloudless night and looking up. The moon has fallen below the horizon and in its absence you see a night sky alight with cosmic presences. What do these pinpoints of light mean to you? Do they represent scientific objects like stars, nebulae, and galaxies, or do you think about the worlds that might orbit invisibly? Does such a view inspire questions of creation, or whether humanity will ever find connection beyond our planet?

Exoplanet astronomers—those searching for and studying planets in orbit around stars other than our own—offer a particular cosmology of what we might ponder when gazing up at the night sky. In white papers, in conferences, and during interviews, astronomers tell of a not too distant future when a scientist, accompanied by her children, points up to the sky. The children ask their astronomer mother to point to a specific star: show us, they ask, the star her telescope has been studying. The mother directs their gazes to that star and explains that around that star scientists have found a planet just like Earth—one that we could inhabit.

When I began my anthropological study of exoplanet astronomers and planetary scientists in 2009, I was interested in their scientific practices. How did these distant, invisible scientific objects we call planets become worlds and places? In my book recounting this research, Placing Outer Space: An Earthly Ethnography of Other Worlds, I focus on epistemological invocations of place in planetary science and suggest that place is not just a passive canvas on which action occurs but an active way of knowing worlds. Even when place is not self-evident, as perhaps with invisible exoplanets, it is drawn upon in order to generate scientific knowledge. Place breathes meaning into alien worlds because it makes these worlds familiar and, moreover, familiar as something that is physically explorable. Places are exciting because we know how to know them; we all have experience learning what it means to be somewhere.


When I asked the astronomers I worked with why this remapping of the cosmos was necessary or meaningful, conversations that had been nuanced and personal turned abstract and stilted.


Throughout my book, then, I discuss how place is part of the scientific process of knowing the universe. This explanation, however, doesn’t fully capture the ontological importance of understanding planets as worlds. What is the significance of the promise exoplanet astronomers make to themselves and others that one day they will be able to point up to the night sky and identify a world like our own? This gesture of connection requires knowing that something is there at which to point. It signifies a changing geography of the cosmos and reflects the sentiment repeated again and again by exoplanet astronomers: that finding an Earth-like planet will change how humans view “our place” in the universe. Figuring Earth as one of many places that humans can be on, one of many places in the universe, creates an interplanetary network that planetary scientists have become comfortable inhabiting.

When I asked the astronomers I worked with why this remapping of the cosmos was necessary or meaningful, conversations that had been nuanced and personal turned abstract and stilted. In one typical example, I asked a graduate student about the relationship between exoplanet astronomy and astrobiology. He quickly responded that “in the end, everyone wants to know if there’s other life, so I think even with me [studying the shape of exoplanets] that kind of drives what I’m doing. In the end, we want to find other Earths, we want to find something similar to us.” When I asked him to explain this drive for finding other Earths or other life, he had trouble articulating an answer:

Uh, I don’t know, uh, relevance? Our own? I don’t know, in some sense, uh, I don’t know, the scale of things? I don’t know, the basic question of how common we are? I’m not a very religious person, so for me it just seems likely and I don’t want to feel anthrocentric [sic] or Earth centric in some sense, I want to see that validation that you know it’s more than just us in some sense. I don’t know, that’s not very articulate. It’s just interesting, childlike interest. I don’t know. This is the same interest I had when I was really young so obviously it must be something important.

This statement mixes together different ways one might frame one’s professional goals: from the quantifiable question of how large the universe is to the abstract notion of humanity’s relevance in such an expansive universe. The way this graduate student reflected on his chosen path brings to mind a vocational calling, one that was, for the student, unavoidable precisely because its profound implications were “obvious.”

In this essay, I wish to reflect on the “obviousness” of the objective of planetary science’s search for worlds and life like our own. What do understandings of what is “out there,” that is, our scientific and cultural cosmologies, tell us about what it means to be in the universe? Though exoplanet astronomy is a relatively small and new field (the first exoplanet orbiting a star like our sun was discovered in 1995), the promise of finding a planet like our own has captured the popular imagination. The future this field promises—of being able to identify such a world—is a cosmology animated by connectivity. Earth is part of a planetary network brought into being by the scientific work that transforms planets into places. It has therefore finally become a possible task to know our own place in the universe.


Today’s exoplanet astronomers are of course not the first to ask after the existence of other worlds. As many scholars have documented, this question was asked in antiquity and has rarely receded from philosophical, theological, and scientific agendas. Exoplanet astronomers make frequent reference to one of the earliest askers of this question, regularly quoting Epicurus’s musings on the existence of infinite worlds. In his letter to Herodotus, Epicurus’s statement about many worlds is made in the broader context of outlining his theory of the material world consisting of infinite “atoms.” For Epicurus and other atomists, evidenced by the later writings of Lucretius, the existence of other worlds was a conclusion to be drawn from their theory of matter, not a sought-after answer to a specific question.

The atomists believed in an infinite, unbounded universe (and one that lacked divine guidance) in contrast with the Aristotelean model of a finite universe governed by a “prime mover.” In an Aristotelean universe, the fixed stars represented not only the end of the perceptual cosmos but also the end of all being. For the atomists, the multiple worlds whose existence they intuited lay beyond the fixed sphere of the heavens. Each world had its own surrounding spheres and stars. (To be clear, this ancient understanding of infinite worlds is more closely related to contemporary notions of parallel universes then to exoplanet astronomy, insofar as their existence lies outside empirical study. Such other worlds could not be physically pointed to but served as the completion of thought experiments on the ramification of the atomists’ theories.) For Epicurus and his followers, then, their speculations on infinite worlds were inseparable from questions of theology and metaphysics. Stating the existence of other worlds was not primarily about answering the question of whether we are alone in the universe but was concerned with limiting the invocation of the divine as explanations for Earth-ly actions.

The demarcation of scientific questions from theological questions is of course a relatively recent occurrence. An example of one of the earlier attempts to present the latest understandings of the universe separate from theological conversation can be found in the writings of Bernard le Bovier de Fontenelle, who worked to convey the new knowledge of the post-Copernican cosmos to a popular audience during the French Enlightenment. In 1686, Fontenelle published Entretiens sur la pluralité des monde, which was translated into English in 1687 as Conversations on the Plurality of Worlds. It is written as a conversation between a teacher and a naïve woman, in a progressive attempt, Fontenelle explains in his introduction, to make these exciting ideas accessible to women as well as men.

Conversations proceeds by explaining the heliocentric model of the universe, speculating on the Moon as an inhabited world, offering information on the other known planets, and finally suggesting that every “fixed star” is itself a Sun with orbiting worlds. On the broaching of this idea, the pupil exclaims, “Here’s a universe so large that I am lost, I no longer know where I am, I’m nothing”.[i] This feeling of being lost is reiterated when the student considers that these worlds might each be inhabited: “We ourselves, to whom the same phrase [inhabitants] applies—admit that you’d scarcely know how to pick us out in the middle of so many worlds. As for me, I’m beginning to see the Earth so frighteningly small that I believe hereafter I’ll never be impressed by another thing”.[ii] Such exclamations serve as a foil for Fontenelle, acting the wise teacher, to reframe such fear as excitement: “Now that they’ve given infinitely greater breadth and depth to this vault by dividing it into thousands and thousands of vortices, it seems to me that I breathe more freely, that I’m in a larger air, and certainly the universe has completely different magnificence. Nature has held back nothing to produce it; she’s made a profusion of riches altogether worthy of her.”[iii]


From the grey, dusty Moon, astronauts talked about the beauty of the Earth, glowing blue in a sea of blackness.


The idea of many worlds, in this interchange, no longer concerns the role of divinity but has become a more personal question. How does it feel to think of other worlds: is it alienating or exciting? Fontenelle, through the voice of the tutor, clearly invites his Enlightenment audience to turn away from the fear of this enormity and embrace its possibility. Yet this anxiety over losing oneself in the universe persists. As the space age loomed and the reality of humans traveling beyond Earth came into being—three centuries after Fontenelle’s writing—we hear echoes of the fictional student. Would human spaceflight bring about the physical dislocation of humanity from earth and thus a change in how we know ourselves and our place in the universe?

In the heat of the space race, when the US and the USSR were neck and neck, the Italian writer Italo Calvino published a haunting story speaking to the concern of terrestrial alienation. In “The Distance to the Moon,” Calvino describes a time when the Moon was much closer to the Earth. The narrator of this story, accustomed to jumping back and forth between the two spheres, was startled to find himself stranded on the Moon as it quickly began drifting away from the Earth. During this unexpected exile, he realized how much he defined who he was with respect to his relationship to Earth:

I thought only of the Earth. It was the Earth that caused each of us to be that someone he was rather than someone else…. I was eager to return to the Earth, and I trembled at the fear of having lost it… torn from its earthly soil, my love now knew only the heart-rending nostalgia for what it lacked: a where, a surrounding, a before, an after.[iv]

When astronauts finally did leave Earth’s surface and atmosphere, they became the first to understand what it would mean to return to Earth. From the grey, dusty Moon, astronauts talked about the beauty of the Earth, glowing blue in a sea of blackness. But even as a small portion of humans became spacefaring, the fear that Earth would diminish into an inconsequential speck rang false. Rather, one may argue that the view of Earth from space did just the opposite. Earth, seen as a planet, became an important rhetorical image for the dawning of ecological consciousness.


Today, nearly a half century after humans visited the moon, there is a different cosmology that motivates the scientific exploration of the cosmos. Scientists do not see their work as explicitly bolstering a theological stance, as did Epicureans, nor do they need to offer comfort to a population still adjusting to a post-Copernican worldview, as Fontenelle felt compelled, or offer provocation to a population anticipating human space flight, as Calvino did.

In fact, whereas the student in Fontenelle’s Conversations is disoriented by learning of the possibility of multiple worlds, today’s exoplanet astronomers are suggesting that to not know of these worlds would be alienating. In

March 2009, just before NASA’s Kepler space telescope (dedicated to searching for exoplanets) launched, a New York Times article asserted the significance of finding an Earth-like planet: “Someday it might be said that this was the beginning of the end of cosmic loneliness.”

That knowing of the existence of other planets will make humans feel less alone is what distinguishes the contemporary conversation on the plurality of worlds from previous iterations. It is also why placemaking figures so prominently. We will only be less alone if we can connect with, imagine being on, and thus being in place on, these other worlds.

Scholars have cited increased loneliness and solitude as a by-product of the changing role technologies are playing in daily life. Yet exoplanet astronomers are arguing that it is through the grand technological feat of detecting a world like our own that humans will finally feel less cosmically alone. The question of “our place in the universe,” astronomers claim, will finally be answered. This answer will come in the form of a detection of a habitable, Earth-like planet. This is an astronomical object made into a very specific kind of place—one whose surface and atmosphere are imagined in great detail, even if the life that might lurk on that surface remains indeterminate. This is the planet to which astronomers hope to one day be able to point; to connect our terrestrial way of being with a cosmic way of being. This, they claim, will neither aggrandize nor diminish Earth but will allow us to finally know Earth, for we will come to know how Earth relates to other planetary places.

Regardless of the time or the reigning cosmology, then, speculating on the plurality of worlds provokes thinking not only about the universe but about Earth itself. Ideas of what it means to be on Earth shape studies of other planets, and studying the habitability of other worlds refines how we define life on Earth. Place draws together this intergalactic network, serving as a metric of meaning-making and analogy.

To speak of a “planet” is never to speak of an isolated body. Today’s planetary scientists are constantly configuring connections and comparisons. How, then, can this comparative planetology also inform humanistic discussions about our own planet? What questions might we raise if we take seriously the astronomical claim that to know Earth and to know ourselves requires that we know other worlds? The planetary imagination is fluid and changing, just as our own sense of Earth as a planet and a place must be. We can learn from planetary scientists that these changes are part of a broader, universe-spanning cosmology. Placing outer space draws a new cosmos, but also points to how other worlds matter for being on this world.

Lisa Messeri is an assistant professor of sociocultural anthropology at Yale University. Her research explores the relationship between place-making and scientific and technical practices. She is conducting research for her next book about the virtual reality community in Los Angeles. Finder her on twitter @lmesseri, where she tweets about space, science, and sometimes politics.

This piece is adapted from Placing Outer Space: An Earthly Ethnography of Other Worlds, Copyright Duke University Press, 2016.


[i] Bernard le Bovier de Fontenelle, Conversations on the Plurality of Worlds, trans. H.A. Hargreaves (Berkeley: University of California Press, 1990), 63.

[ii] Ibid., 63-4.

[iii] Ibid., 63.

[iv] Italo Calvino, Cosmocomics, trans. William Weaver (New York: Harcourt Brace & Company, 1965), 14.


Image courtesy of the author.


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