Earths

In 2012, an infographic depicting how much land (and atmosphere) would be necessary in order to sustain the world’s seven billion people if they lived like the populations of various countries went viral. The graphic sounded a familiar alarm: that resources from more than one Earth would be necessary to support a world full of Americans, Chinese, or even Nepalese people. The data for these models came from the Global Footprint Network. Much like the Club of Rome, whose influential Limits to Growth popularized this kind of global model over forty years ago (Edwards 2010, 366–72), the Global Footprint Network has been criticized for scaling up fragmented and flawed measurements to make claims about the Earth in its entirety.

It has been argued that monotheism became a prominent force in the world because of the symbolic and ideological power of “the logic of the one,” that is, counting to one and no more: not only one deity and one holy book, but also one life and death, one ruler and one people (Schneider 2007). A similar argument could be made regarding the rise of environmentalism. The importance of one Earth, considered as a totality, emerged in tandem with early space travel and rising concerns about an imminent nuclear apocalypse. Between 1968 and 1970, Stanley Kubrick’s 2001: A Space Odyssey was the top-grossing film in the United States, the first photographs of the entire Earth were taken from space, the Treaty on the Non-Proliferation of Nuclear Weapons came into effect, and Earth Day was celebrated for the first time.  

One Earth doctrine, or terracentrism, is now environmentalist orthodoxy. And yet, the last forty years have also seen the rise of an obverse mode of accounting. While some satellites and imaging devices point inward—quantifying deforestation, sea level rise, or melting polar ice—others point outward, enumerating the many Earth-like planets that lie beyond our solar system. These initiatives, much like those of the NewSpace entrepreneurs and advocates who seek to commercialize outer space, are emerging at a precarious time of widespread ecological disaster and financial and political crisis (Valentine 2012). Arguably, NewSpace initiatives and the search for many Earths are also driven by terracentrism: a single planet to escape or transcend, on the one hand, and to measure all others by, on the other.

Consider the Drake Equation developed in 1961, which offers a probabilistic assessment of the number of galactic civilizations we might discover, represented as N (see Denning 2011):

N = R* · ƒp · ne · ƒl · ƒi · ƒc · L

The first three values are the least controversial. They refer to the average rate of star formation in our galaxy (R*), the fraction of those stars with planets(ƒp), and the average number of planets per star that are capable of supporting life (ne). The equation makes assumptions, of course, about what can sustain life (planets orbiting stars) and what those planets must be like (Earth). While the specific values can be assessed in various ways through astronomical observation, the only source for the structure of this formula is the one planet that we know supports life: our own. The final four values are hopelessly controversial, standing for the fraction of planets that go on to develop life (ƒl) and then intelligent life (ƒi), the fraction of those that develop technology capable of releasing detectable signals (ƒc), and the length of time it would take for such civilizations to release detectable signals into space (L).

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Spiral galaxy captured by the Hubble Telescope. Photo by NASA.

With the launch of NASA’s Kepler Space Observatory and the construction of new massive telescopes, new data is available about distant planetary bodies. These studies no longer rely on detecting alien signals, and focus only on the first two or three values of the Drake equation to see if the conditions of life could potentially exist on one of those distant bodies just as they are thought to have existed on Earth in the past. The presence of water, in particular, becomes the difference that makes a difference in the multiplication of Earths. New models and stories multiply the number of Earth-like planets into the probable billions (Petigura, Howard, and Marcy 2013). But this assumes that the many will follow the model of the one. One might insist, to be sure, that the one time we know life happened is all we have to go on. Yet familiarity with the contingencies associated with the emergence of life, intelligence, and civilization suggests caution. Couldn’t life, intelligence, or civilization start and then stop countless times without enduring? Couldn’t death and outright extinction—the death of death—be the rule of the galaxy? If so, the dead, the ignorant, and the uncivilized might be worth counting instead. It is probably the threat of these opposites that haunts our quest to count Earths—the many and the one—in the first place. Extinction means counting down from our one habitable planet, maybe one of very few, to zero.

Models of the one Earth are a recent and impressive accomplishment. But they are just models: all-too-human products based on the scaling up of inevitably partial and situated data. As Graham Harman (2011, 91) argues, “While appeals to the supposed ‘world as a whole’ always have an automatic air of intellectual gravitas and philosophical depth, there is no good reason to think that such an encompassing whole even exists.” One could argue, in fact, that we inhabit many Earths, not one. Not only do we see the Earth change in terms of epochs, but there are many ways of modeling its internal processes and external relations with other celestial bodies and forces, some of which destabilize the popular image of a lone, blue marble.

We continue to count down and count up nonetheless—from one Earth to none, and from one Earth to many possible Earths.

References  

Denning, Kathryn. 2011. “‘L’ on Earth.” In Civilizations Beyond Earth: Extraterrestrial Life and Society, edited by Douglas A. Vakoch and Albert A. Harrison, 74–83. New York: Berghahn.  

Edwards, Paul N. 2010. A Vast Machine: Computer Models, Climate Data, and the Politics of Global Warming. Cambridge, Mass.: MIT Press.

Harman, Graham. 2011. The Quadruple Object. Washington, DC: Zero Books.

Petigura, Erik A., Andrew W. Howard, and Geoffrey W. Marcy. 2013. “Prevalence of Earth-sized Planets Orbiting Sun-like Stars.” Proceedings of the National Academy of Sciences 110, no. 48: 19273–78.

Schneider, Laurel C. 2007. Beyond Monotheism: A Theology of Multiplicity. New York: Routledge.

Valentine, David. 2012. “Exit Strategy: Profit, Cosmology, and the Future of Humans in Space.” Anthropological Quarterly 85, no. 4: 1045–68.