Read an Excerpt
DYING PLANET
Mars in Science and the Imagination
By ROBERT MARKLEY DUKE UNIVERSITY PRESS
Copyright © 2005 Duke University Press
All right reserved. ISBN: 978-0-8223-3638-9
Chapter One
"A Situation in Many Respects Similar to Our Own": Mars and the Limits of Analogy
CRUSOE ON MARS
In the third volume of Robinson Crusoe, the little-read Serious Reflections, Daniel Defoe's hero describes a conversation with a friend "upon the common received notions of the planets being habitable, and of a diversity of worlds." This discussion, Crusoe tells the reader, leaves him "for some days like a man transported into these regions myself" (Defoe 1903, 268). But unlike many of his contemporaries, Defoe rejects the popular view that other planets are "qualified for the subsistence and existence of man and beast" (273). Although Crusoe's imagined flight through the solar system is devoted to describing his "Vision of the Angelic World," his comments about Mars are both scientifically prescient and ideologically revealing. On Mars, says Crusoe, "the light [from the sun] is not above one-half, and its heat one-third of ours [on Earth]." Nevertheless, "this planet is hot and dry, and would admit of no habitation of man, through the manifest intemperance of the air, as well as want of light to make it comfortable, and moisture to make itfruitful; for, by the nature of the planet, as well as by clear-sighted observation, there is never any rain, vapour, fog, or dew in that planet" (274). Crusoe, of course, is an expert on what it takes to survive in a wilderness, and his Mars is more barren and inhospitable than any desert island. Hot, dry, and dark, the planet lacks an earthlike ecology and consequently the resources-water, flora, and fauna-necessary to sustain human existence.
Defoe's description of Mars registers some of the crucial concerns of eighteenth- and nineteenth-century thinkers who speculated about the possibility of life on the planet, and his emphasis on evidence obtained by "clear-sighted observation" anticipates the terms of subsequent scientific debates. Well into the twentieth century, controversies about conditions on Mars, and therefore the usefulness of analogies between that planet and Earth, centered on the problems of identifying the limit conditions for extraterrestrial biota. For Defoe and his contemporaries, habitability translated into questions about the resources that could be exploited by indigenous inhabitants. In a preindustrial world, dominated conceptually by agricultural metaphors, the analogy between Earth and Mars (or any other world) depended less on abstract speculations about the possibility of life than on the lived experience of environmental pressures and resource extraction-the complex interactions necessary to sustain what Defoe calls "the vegetative and sensitive life" (273). In this respect, "clear-sighted observation" implies not only atmospheric clarity and an unbiased observer but an economy of inference that translates visual data into hypotheses about planetary ecology.
The idea of a diversity of worlds consequently has georgic connotations well into the nineteenth century because "intelligence" is defined implicitly and explicitly in terms of resource extraction, agricultural production, and energy consumption. Although we hardly think of Crusoe as an astronomer, his description of a lifeless Mars suggests paradoxically why the red planet fascinated generations of fiction writers and their readers. As the urtext of Western "man's" conquest of the wilderness, Robinson Crusoe offers its readers a thought experiment to ponder the resourcefulness and technological ingenuity that an individual needs in order to thrive in an alien environment. Though Defoe's novel has been read as an exemplar of the Protestant ethic, an adventure tale, and a colonialist parable, it is also a tale of European "man" transforming an island ecology into a protoeconomy, exploiting the indigenous resources necessary to live in comfort. A "plantation," Crusoe calls his island, with cultivated fields, domesticated animals, foodstuffs, utensils, storage vessels for surplus goods, protective fencing, a summer house, and cottage industries in butchering goats, tanning their hides, and producing goatskin garments. For Crusoe, the island is a reservoir of abundant resources; it is, in a sense, the antithesis of his vision of Mars. Yet as the "common received notions" of his time suggest, many of his contemporaries were willing to entertain the idea that similar resources could be found and put to use on the fourth planet. By the end of the eighteenth century, the earthlike ecology of Mars was accepted generally as a scientific fact.
The tale of Crusoe's survival on a desert island hovers over a century of interplanetary science fiction and scientific speculation. In 1964, film director Byron Haskin updated Defoe and sent an American astronaut to the red planet in Robinson Crusoe on Mars. Shot on location in Death Valley, the film depicts Mars as a terrestrial desert. As a visual analogue for three centuries of areological speculation, Death Valley seems the logical extension of Defoe's vision of a planet without the water that would allow indigenous life-forms, or space-age colonists, to prosper. By restaging the Crusoe myth on a hostile, barely habitable planet, Haskin draws on a long tradition of speculation about the Martian environment and the life it might harbor. The limits of the film's analogy define the ways in which our fascination with the red planet depends, as Defoe intuited, on finding the food, water, and air necessary to make it a "fruitful" abode of intelligent life. Scientists studying Mars in the 250 years between Defoe's novel and Haskin's film refined questions about life on the planet, but could provide no definitive answers.
In this chapter and in chapters 2 and 4, I explore the scientific implications of the questions about the ecology of Mars in the era before space-flight, and in chapters 3 and 5 I discuss a long tradition of science fiction that rejected Defoe's dead world and let loose provocative fantasies of a dying planet and its tenacious inhabitants. The need for "clear-sighted observation" encouraged astronomers to improve telescopes and develop new instruments to try to settle debates about conditions on the fourth planet. For three hundred years, Mars has remained a key site for debates about the nature of visual evidence in planetary astronomy, the role of inference and probability in scientific speculation, and the ways in which traditional value systems-Christian theology and anthropocentric philosophy-respond to the Copernican decentering of humankind in the universe. While Defoe remained a skeptic, most of his readers in the nineteenth and twentieth centuries rejected his reasoning and perceived Mars as an older and smaller version of Earth.
THE COPERNICAN REVOLUTION AND THE PLURALITY OF WORLDS
For a few weeks every twenty-six months, Mars and the Earth are aligned on the same side of the sun in their elliptical orbits. During these periods of opposition, Mars is visible through comparatively small telescopes, and, since the mid-seventeenth century, scientific observations of the planet's surface and atmosphere have clustered during these periods. Because the orbit of Mars (compared to Earth's) is an elongated ellipse, its distance from the sun-and from Earth-varies significantly. The eccentricity of its orbit means that Mars may approach as close as thirty-four million miles to Earth when the two planets are aligned on the same side of the sun (as it did in 2003) or remain as far away as sixty-three million miles (as it did at the opposition of 1948). During its nearest perihelic oppositions Mars appears almost twice the size (25.0 seconds of arc) as it does at its most distant (13.8 seconds of arc). As the ancient civilizations of Europe, Asia, and the Americas knew well, Mars appears as one of the brightest objects in the sky, and slowly traces a great loop through the constellations as the Earth overtakes and passes the slower orbiting planet; a Martian year at 687 days is almost twice as long as Earth's. Against the relatively fixed backdrop of the stars, Mars appears to move backward, and this retrograde motion fascinated the astronomers and stargazers of the ancient world. The Chinese called Mars Ying-huo, the fire planet; the Greeks identified it with Ares, the god of war; the Babylonians termed the planet Nirgal, the god of the underworld; and the Aztecs saw in the fiery and erratic Mars the deity Huitzilopochtli, the destroyer of people and civilizations. For these cultures, the trajectory and appearance of the red planet seemed to symbolize the violence and uncertainties of existence (Burgess 1990, 5-7).
The retrograde motion of Mars historically posed difficulties for models of the solar system because it seemed to violate human notions of how a fixed empyrean, an ordered universe, should behave. The Ptolemaic system placed Earth at the center of the cosmos and tried to account for Mars's retrograde motion as well as the less-pronounced retrograde motion of Jupiter and Saturn by adding epicycles to the perfect circles of the planetary orbits. As observational data became more precise, Ptolemaic systems became increasingly complex in their efforts to explain the planets' apparent motion and to reaffirm geostationary models of the universe. By the late middle ages, the geocentric solar system was overwritten with epicycles, and yet it still failed to conform precisely to the observed motion of the planets (Randles 1999, 32-57; Koyré 1957; Grant 1994). But the ideological significance of an ordered universe dictated that the church uphold its age-old vision of a geocentric universe with humankind at its cosmological and moral center. In 1514, Nicholas Copernicus (1473-1543) circulated an anonymous pamphlet that challenged the Ptolemaic universe by placing the sun at the center of the solar system and relegating the Earth to merely another orbiting planet. Although he served as a canon at the cathedral of Fromborg, and therefore was ostensibly bound to uphold the church's position, Copernicus devoted much of his life to developing a heliocentric model of the solar system in an effort to simplify the byzantine complexities of Ptolemaic epicycles into a coherent model of planetary motion. Central to his argument was a rejection of the Ptolemaic explanation of retrograde motion. Copernicus described the backward track of the outer planets, particularly Mars, as an effect of the relative speeds at which they and the Earth orbit the sun. In 1542 he published The Revolutions of the Heavenly Spheres, which presented his heliocentric model, emphasized the "vast magnitude" of the visible universe (with other stars at the centers of their own solar systems), and suggested that gravity was not centered solely on a stationary Earth. His nervous publisher prefaced the treatise with a disclaimer that labeled his work a mathematical speculation, but Copernicus himself seems to have believed in the reality of his theory.
The Copernican theory was not an overnight success, but it provided the impetus for Johannes Kepler (1571-1630) to describe precisely the orbits of the planets. Committed to a quest for cosmic harmonies that would demonstrate the workings of divine providence, Kepler devoted years of his life to the elaborate mathematical calculations that led ultimately to his three laws of planetary motion. In The Mysteries of Cosmography (1596), the first wholeheartedly Copernican treatise on the solar system since Copernicus's death, Kepler argued that the orbits of Mercury, Venus, Mars, Jupiter, and Saturn could be inscribed in the five regular polyhedrons. The universe, he believed, must exhibit the geometrical proportions that he and his contemporaries saw as evidence of divine order. Although he was a Protestant, Kepler reiterated a logic that dominated planetary astronomy during the seventeenth century: any calculations of celestial motions had to fit preordained assumptions about the ultimate harmony of the cosmos; in turn, that harmony confirmed a heliocentric-and divinely ordered-solar system (Paxson 1999, 105-23). Having succeeded Tycho Brahe as imperial mathematician in 1601, Kepler was directed by the Holy Roman emperor to prepare a massive chart of planetary positions. He spent several frustrating years trying to find a mathematical way to account for the orbit of Mars, the most eccentric among the then known outer planets. In The New Astronomy (1609), Kepler admits he "was almost driven to madness" by the years of calculation before he recognized that the paths of all the planets were ellipses with the sun at one foci. His work was subtitled Commentaries on the Motions of Mars.
Kepler's understanding of planetary motion marked a significant advance over the Copernican model and challenged the Ptolemaic universe conceptually as well as mathematically. While locating the sun at the center of the solar system, Copernicus viewed the heavens as a distinct realm from Earth; he made no connection between the forces that kept the planets in their orbits and the everyday effects of gravity on Earth. In contrast, Kepler sought a universal physical law to explain planetary motions-a law based on familiar principles of terrestrial mechanics. His recognition that planetary orbits were determined by gravitational forces liberated the planets from the crystalline spheres of medieval astronomy and gave them a corporeal reality. Even though Kepler's lifelong quest to unify mathematics, astronomy, music, and theology ultimately fell short of a grand synthesis, his commitment to the ideas that the solar system embodies a perfect, theocentric, order and that God does nothing in vain guided subsequent thinking about the physical nature of the planets as well as their motions. By vastly extending the dimensions of the universe, Kepler, like Copernicus, raised the possibility that the stars were other suns and that other planets, too small to detect from Earth, might be orbiting other heliocentric systems. The cosmos, then, might well harbor a plurality of inhabited worlds.
By the early seventeenth century, the Moon, Mercury, Venus, Mars, Jupiter, and Saturn had become refracted images of Earth, possible worlds rather than mere lights in the sky. Giodorno Bruno was burned at the stake in 1600 for his heretical beliefs, including his faith in a scientific knowledge "which freeth us from an imagined poverty and straitness to the possession of the myriad riches of so vast a space, of so worthy a field, of so many cultivated worlds" (quoted in Guthke 1990, 69). A century before Defoe, Bruno redefined the geocentric conception of the planets into a dynamic model of resource-using, intelligent beings. It is significant that Bruno defines "worlds" in terms of "myriad riches" and "cultivation"; the transcendence from "poverty" to "riches" is material as well as metaphysical, ecological (in the broadest sense) as well as theological. "Cultivated worlds" clearly implies rational beings to do the cultivating, and these beings posed a threat to a religious orthodoxy that placed "man" at the moral center of creation. A just and merciful Supreme Being who created intelligent life elsewhere in the universe, Bruno reasoned, presumably would supply those beings with the capacities, resources, and opportunities to transform raw materials into material comforts, as humankind had done on Earth. The alternative-lifeless planets that had no discernible function in a divinely created universe-would threaten the bedrock principle of seventeenth-century natural philosophy: each aspect of creation fulfills a divine, if mysterious, purpose.
(Continues...)
Excerpted from DYING PLANET by ROBERT MARKLEY Copyright © 2005 by Duke University Press . Excerpted by permission.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
