I gave a TEDx talk two weeks ago about my new book, The Lost White Tribe: Explorers, Scientists, and the Theory that Changed a Continent, which will be coming out in January with Oxford University Press. TED talks are supposed to be short. It was a challenge to figure out how to convey the key story line of the book in 15 minutes. I hope it works. Let me know what you think.
On 14 July 2015, the New Horizons spacecraft will make its closest approach to Pluto, passing within 6000 miles of the dwarf planet. As the piano-sized machine begins to stream high-resolution images of Pluto back to earth (which even the Hubble telescope perceives as a murky blob) I thought it would be a good to take a minute and consider the story of Pluto’s discovery in the early decades of the twentieth century.
At this time, Pluto was known as Planet X. Like most stories of discovery, the story of Planet X seems straight-forward at first, then gets more tangled the deeper one digs. It is worth disentangling. The story of Pluto reveals a bigger story about scientific discoveries and the difficulties of attributing credit.
Here’s the straight forward part. On 18 February 1930, Clyde Tombaugh sat in the Lowell Observatory and compared photographic plates taken of the same patch of sky on different days. He was looking for a misalignment of objects from plate to plate — something that would indicate the motion of a comet, asteroid, or planet against the backdrop of stationary stars. The density of stars on the plates made this a nightmarish task — a celestial Where’s Waldo with millions of objects to consider. Yet with the assistance of a blink comparator — a machine that strobes two images back and forth repeatedly — Tombaugh perceived a tiny object moving across the star field. He had discovered a distant planet circling the sun, one forty times more distant than the earth.
This was Planet X. Since the discovery of Neptune in 1846, astronomers had searched excitedly for planets in more distant orbits. Much of this excitement grew out of the way Neptune had been discovered. In the year before it was sighted by Johann Gottfried Galle, Neptune had been predicted by Urbain Le Verrier based upon irregularities in the orbit of Uranus. Put simply, Uranus did not seem to be behaving in accordance with Newton’s laws of motion. At one point in its orbit, Uranus moving faster than predicted. At another point, it moved more slowly. The strange behavior could be explained, Le Verrier argued, by the existence of an planet beyond Uranus that exerted a gravitational pull upon the seventh planet. Le Verrier’s prediction proved correct.
This was the kind of discovery that brought astronomers to the edge of rapture. Finding Neptune did not arrive by luck or serendipity. It did not appear from some brute process of sorting and observation. It was predicted by the powers of human calculation. It became visible through Le Verrier’s feat of mathematical prediction. He had summoned it, and it had appeared. French physicist Francois Arago marveled at this. “He discovered a planet through the point of his pen.”
Inspired, astronomers began looking for irregularities in Neptune’s orbit as well. Meanwhile, others looked to the orbital radii of comets, which they believed might also point to the influence of a distant unknown planet. By the late 1800s, the astronomical community had become a roadside revival for the prediction of trans-Neptunian planets. As Morton Grosser points out in his 1964 Isis article “The Search for a Planet Beyond Neptune,” the quest for the trans-Neptunian planet “was a kind of celestial grail, and repeated failures to find it seemed to attract new searchers rather than to discourage those already seeking.” (It’s interesting to note that, at exactly the same time, polar explorers were approaching the North Pole with the same giddy attitude and language; see for example Elsa Barker’s 1908 poem “The Frozen Grail.”)
In 1915, Percival Lowell tried to weigh the merits of these multiple predictions, all of which were based upon different sets of observational evidence. The exercise was a daunting one, yet in working it out, Lowell seems to have crossed a threshold in his own thinking about his craft, one that makes him sound more like a philosopher of science than an astronomer hunting for planets.
The theory of a planet cannot in the nature of things be exact; and this for three reasons:
1) The observations on which it is founded are necessarily more or less in error;
2) The theory itself may be more or less imperfect
3) An unknown body may be acting of which perforce no account has been given
Nevertheless, Lowell came down to earth long enough to make a prediction of his own. Planet X did exist. It could be located in a an orbit of forty-three astronomical units (where 1 au = distance between the sun and the earth). In mass, it would be twice as big as the earth. Lowell died in 1916 but the quest to find Planet X continued. When Tombaugh found the flickering spot of light in his blink comparator in 1930, it seemed to be vindication for Lowell’s prediction. When the name “Pluto” was offered by 11-year old Venetia Burney from Oxford England, it found approval at the Lowell Observatory. The name — representing the Roman god of the underworld — seemed suitable for a planet that was so cold, dark, and distant. Moreover, the symbol of the planet would be cast as ♇, which also functioned as a monogram for Percival Lowell.
Yet from the very beginning, Lowell’s status as discoverer was controversial. Astronomers noted that while Lowell’s prediction was in the neighborhood of Pluto’s position, it wasn’t an exact fit. Nor was it clear that Pluto was big enough to exert a gravitational effect upon Neptune big enough to explain the irregularities of Neptune’s orbit. In 1951, a paper by V. Kourganoff vindicated Lowell’s prediction, and there matters stood until 1978 when astronomer Robert Sutton Harrington of the US Naval Observatory determined that the mass of Pluto, at 1/500th the mass of the Earth, was too small to influence the orbital path of Neptune. Lovell’s prediction — through no fault of his own — fell short according to errors in observation, the first point in his 1915 article.
Accordingly, the discovery of Pluto did not follow in Neptune’s footsteps, because it was discovered as a matter of luck rather than of prediction. It seems that Tombaugh was looking at the right place, at the right time, but for the wrong reasons. So should Lowell be stricken from the record of Pluto’s discovery. Should we rename this icy dwarf planet according to other names proposed in 1930: Zeus, Minerva, or Cronus?
Then again, would Tombaugh even have been looking for Planet X if Lowell had not made such a persuasive case for finding it there? Certainly there was a degree of luck in finding Pluto. Yet, it was a discovery that also required powerful equipment, careful practice, and a dogged conviction that Lowell was right. In this, Pluto takes its place next to a number of scientific and geographical discoveries — from Columbus’s “discovery” of America” to Kepler’s search for a divine planetary arrangement. Unlike Neptune’s “discovery at the point of a pen,” perhaps Planet X’s epitaph should read “Look long enough and you will find it.”
So many books have been written by and about astronauts that it doesn’t seem like there is much left to cover. Yet Matthew H. Hersch breaks new ground in Inventing the American Astronaut (Palgrave Macmillian, 2012) by examining the evolution of the astronaut as a professional class. Space history, as Asif Saddiqi points out in “American Space History: Legacies, Questions, and Opportunities for Further Research,” too easily falls into a number of familiar plot lines — the hero quest, the Cold War race, the triumph of American technology, or the restless spirit of human exploration — all of which drive professional historians completely crazy. Why? Because these plot lines often dictate the direction of the narrative rather than the details of the subject itself.
Hersch doesn’t fall into this trap. The creation of the astronaut corp, he makes clear, could have unfolded differently. Early NASA administrators thought that test pilots — comfortable with technology, accepting of risk, and rigorous in their shakedowns of new planes — would make the best candidates for spaceflight. Once these test pilots entered the astronaut corps, flying the missions of the Mercury Program, they gained authority as popular heroes, influenced the design of spacecraft, and entered the NASA ranks as senior pilots and administrators. Thus established, the test-pilot astronaut became the benchmark by which future candidates were measured. Space scientists, by contrast, were generally ranked lower than test pilots and waited longer for flight assignments. While NASA’s 1958 charter put a priority on “the expansion of human knowledge of the Earth and of phenomena in the atmosphere and space” science was of secondary importance on Mercury, Gemini, and Apollo missions. Moreover, the narrow demographics of military test pilots — almost all of whom were white and male — became the demographic of the NASA astronaut as well. Only in the 1970s and 1980s would this begin to change as women, minorities, and non-test pilot astronauts entered the ranks with the Space Shuttle.
Behind the scenes, astronauts endured hardships that extended beyond the risks of spaceflight. The selection process was highly competitive, but also mysterious. It was unclear which skills — physical, intellectual, interpersonal, or psychological — were most important for obtaining a mission assignment. Once astronauts flew in space, their public and professional cache increased dramatically — as well as their opportunities for future missions. Rookie astronauts, by contrast, lived more precariously — never knowing for certain whether or not they would receive a flight assignment. So while the public viewed astronauts as cool-headed professionals, the reality was less inspiring. The Astronaut Office,wrote NASA engineer Homer Hickam, was producing “bureaucratic combatants with warped personalities” (162).
If this sounds like more like Dilbert than Deep Space 9 it is because Hersch has a larger point, one that he makes convincingly: the astronaut represented a late 20th century professional class, one that demonstrated many similarities to earlier 20th century professionals, particularly middle-class engineers. Even at 25,000 mph, these rocket men could not escape the gravitational pull of the workplace, a force that shaped the arc of their careers from Johnson Space Center to the Sea of Tranquility.
The fate of the Australasian Antarctica Expedition — still stranded in pack ice off the coast of Antarctica — got me thinking about the value of reenacting expeditions. I wrote an opinion piece on the subject for National Geographic. Getting trapped in pack ice isn’t always a bad idea. In 1895, Fridjof Nansen intentionally sailed his ship Fram into the polar pack ice in hopes of reaching the North Pole. While he fell short, he achieved a new “Farthest North.” I will be speaking about this subject on an episode of Mysteries at the Museum, airing on 2 January at 9pm (EST).
I have two longer pieces just out in edited collections: one reassessing the life of notorious North Pole explorer Frederick Cook in North by Degree: New Perspectives on Arctic Exploration, and another reflecting on the long relationship between “Science and Exploration” in Reinterpreting Exploration: The West in the World.
Last year, I helped the curators at the Barnum Museum in Bridgeport CT identify an old sleeping bag in their collection — one that is connected to the rescue of Greely and six of his men in 1884. I’ll be giving a public talk about the subject “The Greely Expedition: A Tale of Triumph and Tragedy in the Arctic.” at the Barnum on 23 February at 2pm.
Fort Conger, Ellesmere Island, November 1881
Only after Adolphus Greely had directed his men to build their long bunk house at Fort Conger, when the long night of winter had descended on Lady Franklin Bay, did he direct the party to begin preparations for using the Peirce No. 1. Greely was a man who, much like Israel, was comfortable with data collection and precision instruments. He had overseen the creation of a vast telegraph network in the U.S. Army Signal Corps, becoming the Army’s top meteorologist. Perhaps this was a reason for the close bond that grew up between the two men. Greely identified a site on the north side of the house, a space sheltered under a canvas lean-to, where the pendulum could be placed. A party began digging the holes and pouring the Portland cement piers that would anchor the instrument. Digging frozen ground in the dark at -30°F wasn’t pleasant work and even Greely, not inclined to complain about conditions, described the process as “tedious and trying.” The men built an ice house around the pendulum frame to protect it from the elements and to stabilize its temperature. They placed a glass window with the wall in order for Israel to record measurements without entering the ice house. Only then did they remove the pendulum from its tin shroud and long wooden case. There, they hung it to swing in its dark, frigid chamber.
The delay in setting up the pendulum was deliberate. Peirce had recognized that the Arctic winter offered special advantages for pendulum use. The frozen ground firmed up the support of the concrete piers, reducing the flexure of the frame that might change the duration of the pendulum’s swing. In winter, the frigid Arctic air was very dry, reducing humidity that would deposit moisture on the pendulum, skewing its weight. Finally, the depth of winter would also bring greater consistency of temperature, important to limit any expansion or contraction of the metal itself.
Yet for Israel, the difficult work was only beginning. The relative simplicity of the Peirce No. 1 belied the complexity of Peirce’s instructions. The Superintendent had given Israel a daunting list of requirements for the pendulum’s proper use. Israel needed to swing the pendulum within a very specific range of motion: not larger than 25/1000ths and not smaller than 5/1000ths of the arc radius. The pendulum had to be swung for ninety minutes, reversed, and swung again for thirty. This series needed to be repeated multiple times, so that the total time of pendulum measurements reached six hours a day.
In addition to marking each swing over time, Israel had to record temperatures as well. Since the thermometer couldn’t touch the pendulum, Peirce directed Israel to set up thermometers near the top and the bottom of the instrument, making sure that each did not vary perceptibly from one another or over the time of the swing. Finally, Israel had to measure the flexure of the frame itself, which Peirce instructed, could not vary more than 1/200th of a millimeter. Although the glass window allowed Israel to measure each swing from the comfortable distance of the house, he still had to swing the pendulum, measure temperature, and look for microscopic flexures of the frame. In the end, Greely records that “for sixteen days in January 1882 he diligently swung Peirce Pendulum No. 1 in a specially constructed ice shelter.” After the sixteen-day series was complete, the pendulum was placed within its slender wood box and sealed once again in tin, to wait for its transport home with the party in the summer of 1882. The entire sequence of the pendulum experiment, from Peirce’s training to Israel’s execution had been meticulously planned and executed. For Greely and his party it represented a triumph of science over sensationalism, one that would contrast sharply and tragically with the catastrophe that followed.
Cape Sabine, Ellesmere Island, 1884
The expedition that came to relieve the Greely Party at Fort Conger in 1882 was turned back by ice. Greely and his men, despondent at the lack of relief, overwintered for a second year and waited for the arrival of a second relief expedition in 1883. Yet this expedition, too, failed to reach Fort Conger, crushed by pack ice in the southern reaches of Smith Sound. As it became clear that the second expedition was not going to arrive in 1883, Greely made preparations to evacuate Fort Conger and travel south in small boats.
The forced retreat created a dilemma for Greely and his men. It was crucial to return the pendulum to Washington so that it could be inspected and swung again by Peirce, confirming the measurements taken at Fort Conger. Yet the pendulum in its tin case and wooden crate added over forty kilograms of dead weight to an increasingly desperate escape effort.
Greely hoped to find stores near Cape Sabine left by the relief expeditions. Yet arriving at the southern reaches of Smith Sound, the party found few provisions. With little hope of finding more food, the party would now have to carry the pendulum as they dragged their boats over the pack ice. Greely took the issue to his men:
I informed the men that I was unwilling, much as I wanted to save that instrument, to lessen their chances of life by hauling it longer, unless all concurred, and that it would be dropped whenever they wished. Not only was there no objection to keeping it, but several of the party were outspoken in considering it unmanly to abandon it. Such a spirit is certainly most credible.’
The men continued to carry the pendulum, stripping off the tin shroud to reduce weight. Eventually, they cached the Peirce No. 1 on Stalknecht Island, just off the shore of Cape Sabine. While it had functioned as a precision instrument in Washington and Fort Conger, the Peirce No. 1 now became a rescue beacon for relief ships entering Smith Sound, its long box anchored as a tower to the rock cairn to make it more visible, a note tucked within the rocks giving the party’s location on Cape Sabine.
During the winter and spring of 1884, the members of the Greely party slowly succumbed to starvation. On 27 May 1884, Israel began speaking quietly of home, his mother’s cooking. He became delirious and died. Greely, who shared a sleeping bag with Israel during their final desperate months, wrote that he “learned to love him like a brother.” When Greely conducted Israel’s burial, he edited the Christian service to make it consistent with the astronomer’s Jewish faith. Twenty four days after Israel died, a rescue party under the command of Winfield Schley arrived at Cape Sabine where they found Greely and six men close to death, the last survivors of the twenty-five men crew. Schley had expected to find Greely further north at Fort Conger, but his men saw the cairn on Stalknecht Island and went to investigate. There, they found the tall pendulum in its box, still projecting upwards from the rocks.
Washington D C., August, 1884
Thousands of well-wishers turned out in Portsmouth New Hampshire to welcome Greely and his men home. The day was filled with speeches and a parade of over two thousand. Speaking of the value of the expedition, Senator Eugene Hale of Maine told the crowds, “Nothing dims its record. There was no insubordination, no blundering, no losing of the head.” Hale’s remarks were premature. As he spoke, evidence was emerging that some members of the party had resorted to cannibalism in their final months at Cape Sabine. The press also discovered that the Greely party was riven by conflicts, especially during the long retreat from Fort Conger when Greely’s officers had almost relieved Greely of his command. As these discoveries swirled in the pages of the popular press, Greely defended himself, the bravery of the party, and the expedition’s commitment to science.
Key to this defense was the party’s unanimous decision to carry the Peirce No. 1 out of the Arctic despite its weight. Greely chronicled this event in his final report, and it also appeared in the Coast Survey report as well as popular press accounts. As a result, the pendulum gained symbolic importance. It was at this moment, ironically, that Peirce began to question the instrument’s scientific value. He had measured the pendulum at the Coast Survey Building in late 1884 and observed that its length and mass had changed significantly since 1881. As a benchmark of Israel’s Arctic measurements, then, the pendulum seemed useless. Greely was furious, defending himself and Israel in a letter that he attached to Peirce’s report. Yet the long brass bar yielded results of a different kind. While it may have failed to measure the contours of the earth, in the eyes of many nineteenth-century Americans, it offered something more valuable in return: a measure of scientific spirit and manly character, one that protected Greely and the reputation of the expedition party in the decades to come.
[This essay was published by the journal Endeavour in December 2012: 36(4):187-90]
 Greely quoted from Three Years of Arctic Service: An Account of the Lady Franklin Bay Expedition, 1881-1884 (New York, 1894) 1:119.
 C.S. Peirce, “General Instructions for Observing Oscillating Pendulums,” (1881) from The Peirce Edition Project, http://www.iupui.edu/~peirce/writings/v6/W6ann/W6ann30.htm
 Introduction, Writings of Charles S. Peirce: 1886-1890 (Bloomington: Indiana University Press, 2000), 6: xxx.
 Guttridge, Ghosts, 151-199.
 Greely, Arctic Service, “Arctic Journal” dated 17 Sept 1883. 1:509-10
 Eugene Hale quoted in William McGinley, Reception of Lieut. A. W. Greely, U. S. A., and His Comrades, and of the Arctic Relief Expedition, at Portsmouth, N. H., on August 1 and 4, 1884 (Washington: Government Printing Office, 1884), 35.
 Rebecca Herzig writes about the value of hardship in the Greely Expedition in Suffering for Science (Rutgers University Press, 2005), 64-84. Also see “The Magnetic and Tidal Work of the Greely Arctic Expedition,” Science 9 (4 March 1887): 215-217; Editorial, Science 4 (1 August 1884): 94; Daniel Gilman, “Reception of the Greely Arctic Explorer, Lieutenant Greely, U. S. A.,” Johns Hopkins University Circulars 4 (March 1885): 54.
Washington D.C., July 1881
Sargent Edward Israel arrived in Washington and made his way up Capitol Hill to the Coast Survey Building. He had an appointment with C.S. Peirce, Assistant at the Coast Survey, who would instruct Israel in the use of scientific instruments needed for the Greely Expedition, scheduled to depart for the Arctic in a few weeks. At twenty-two, Israel was the youngest member of the expedition. He had just finished his degree in astronomy at the University of Michigan where he had impressed faculty with his command of theoretical astronomy. He was comfortable with scientific equipment and well-prepared to do complicated calculations and reductions. Yet the biggest challenge that would face him on this expedition was in the gathering of data. His meeting with Peirce was not merely a lesson in how to use instruments, but how to use them in extreme conditions.
When the Greely Expedition built its station on Ellesmere Island at 81°N latitude, it would be the northernmost outpost in the world, and one of the most difficult places on earth to do science. One of twelve stations to be established during the International Polar Year (IPY) of 1881-1882, the American outpost would record – along with all of the other stations – a variety of terrestrial phenomena including tides, weather, temperature, wind speed, and barometric pressure. The IPY was the brainchild of Austrian explorer, Karl Weyprecht, an attempt to redirect the energies of polar explorers away from flag planting and records of “Farthest North” towards something more substantial: a sustained and systematic program of Arctic research.
When Israel arrived at the Coast Survey Building, he was met by Peirce. The two men descended into the basement and entered Room 6. There, anchored by concrete piers, suspended from a large trapezoidal frame hung a long brass bar, the Peirce Pendulum No. 1. Few people would have identified the object as a pendulum. It did not have a round weight or a thin arm. It was not an object one would find oscillating in the case of a grandfather clock. The Peirce No. 1 was unremarkable except for small projections, “knife edges,” that jutted out of the sides of bar near its top and bottom and allowed the pendulum to hang freely in its wooden frame.
Peirce set the pendulum in motion, swinging it a few centimeters off center. The heavy bar, rocking back and forth on the slender pivot of its knife edges, swept out small, regular arcs. Israel did not record his impressions that day. He would not survive the expedition to write about it later. Perhaps his college experience with the instruments of astronomy, the telescopes that offered him spectacular views of planets and nebulae, made him jaded to the operations of the Peirce No. 1. Yet even someone less experienced with scientific instruments than Israel, some imaginary passer-by who found himself in Room 6 that day, would have struggled to find either drama or meaning in the Peirce No. 1’s slow monotonous motions. It appeared almost too simple to be useful.
Yet it was the monotony of this pendulum that gave it its power. Allowed to swing freely, a pendulum will repeat its journey back and forth in the same period of time, even as the height of its swing diminishes. It did not escape the attention of Galileo or other Renaissance scholars that the regularity of this motion offered a valuable way of measuring time itself. By the 1650s, the Dutch mathematician Christiaan Huygens understood the movement of a pendulum well enough to describe it mathematically:
T = π√(l/g)
where the time (T) of the pendulum’s swing varies directly with its length (l) and indirectly with the force of gravity (g). Assuming that gravity remains constant, the most important variable determining the pendulum’s swing is the length of its arm. By lengthening or shortening this arm, the pendulum can be made to sweep out an arc of desired duration. After Huygens patented his first pendulum clock in 1657, clockmakers developed a “seconds pendulum” that offered a spectacular improvement in accuracy from earlier clocks, reducing error from fifteen minutes to fifteen seconds a day.
By the 1700s, the pendulum had also found more esoteric uses. Since clockmakers had succeeded in showing that a swinging bob could be used as a measure of time, it stood to reason that that swinging bob, marked by increments of time, could be used as a measure of gravity. Gravity appeared to be remarkably stable over time, but was it also stable over distance? On a perfectly spherical earth, this should be the case since the distance between the surface and the earth’s center of mass would never vary. A distortion of the planetary sphere, however, would produce variations in gravity from place to place, ones that might be detectible by the swinging of a pendulum. For this reason, in the 1730s, the French geodetic expeditions of Pierre-Louis Moreau de Maupertuis and Charles Marie de La Condamine carried gravity pendulums with them to the polar and equatorial regions respectively, attempting to resolve a dispute between French geographer Jean-Dominique Cassini, who believed the earth was slightly egg-shaped, and Isaac Newton who was convinced it was squashed like a jelly-donut. The expeditions proved Newton right, but did not give enough data to describe to the shape of the geoid with precision.
This was the objective of Israel and the Peirce No. 1: to determine the precise shape of the earth from the swinging of the pendulum. In so doing, it fit comfortably within the pendulum’s expanding role as an instrument of research, marking a procession of important instruments from Condamine’s pendulum in the 1700s to Foucault’s pendulum in the 1800s. Gradually the pendulum had evolved from a symbol of timekeeping to a symbol of science. As such, it conformed nicely to the broader objectives of the IPY: to reinvent Arctic exploration as something serious, scientific, and collaborative.
As the simple brass bar swung on its knife edges in Room 6, Peirce recorded the duration of its swings. The meeting had provided Israel with a tutorial in operating the pendulum, but it had offered Peirce something equally important: a series of measurements that he could compare with those made by Israel in the Arctic. As they concluded their meeting, Israel departed. In Room 6, the Peirce No. 1 was carefully packed in a long wooden case and sealed with tin. In the days that followed, it was shipped north with other expedition equipment to St. John’s Harbor, Newfoundland where it was stowed below deck on Greely’s expedition ship, Proteus. On 7 July, the ship set sail with the expedition party for Lady Franklin Bay, an inlet on the northeastern shore of Ellesmere Island, the northernmost island in the Arctic Archipelago.
[This essay was published by the journal Endeavour in December 2012: 36(4):187-90]
 I want to thank Dr. Geoffrey Clark for his support in this project. I wrote about Greely’s pendulum briefly in The Coldest Crucible: Arctic Exploration and American Culture (Chicago: University of Chicago Press, 2006), but he convinced me that this instrument was part of a larger story. He has also generously allowed me to use his photos of the Peirce pendulum for this essay.
 William Barr, The Expeditions of the First International Polar Year, 1882-83 (Calgary: Arctic Institute of North America, University of Calgary, 1985). The goals of the IPY did not prevent the Greely Expedition from also pursuing a record of “Farthest North.” Weyprecht’s ideals co-existed with nationalistic and adventurist interests in the Polar Regions.
 C.S. Peirce, “Pendulum Observations” in Report on the Proceedings of the United States Expedition to Lady Franklin Bay, Grinnell Land (Washington, DC.: Government Printing Office, 1888), 2: 701-714.
 The changing amplitude of a pendulum swing does have a small effect on its period, something that Huygens pointed out in his work Horologium Oscillatorium sive de motu pendulorum (1673); Matthew Bennett et al., “Huygens’ Clocks,” Proceedings of the Royal Society of London, (2002) A 458, 563–579; Victor Fritz Lenzen and Robert P. Multhauf, “Development of Gravity Pendulums in the 19th Century,” Contributions from the Museum of History and Technology, Papers 34-44, On Science and Technology (Washington D.C.: Smithsonian Institution, 1966), 305-6, 324-330.
 This assumes the earth’s mass is distributed uniformly.
 Mary Terrall, The Man Who Flattened the Earth: Maupertuis and the Sciences in the Enlightenment (Chicago: University of Chicago Press, 2002).
 Leonard F. Guttridge, Ghosts of Cape Sabine: The Harrowing True Story of the Greely Expedition (New York: Berkeley Books, 2000), 49.
Would you climb an 8000-meter mountain? Descend in a submersible seven miles under the sea? Pilot a shuttle back to earth at 17,000mph? Most of us choose other paths. The astronaut who arcs around the earth every ninety minutes seems to trace out a life faster and wilder than ours down below, where we make the slow orbit from home to work and home again. It’s understandable, then, why we place explorers and adventurers in a category by themselves, honor them with statues, magazine covers, and tickertape parades. Those who take such risks, these travelers of the extreme, seem to shine with a different light. They do otherworldly things and appear, at times, born of other worlds themselves, brought up within the same towns perhaps, attending the same schools, but made alien through the crucible of perilous experience. Or, perhaps, they were alien to begin with, living among us, sharing our food and oxygen, but pushed by different winds, compelled like Icarus to fly towards the sun. We laugh at Tom Wolfe when he tells us that astronauts are made of the right stuff, but we believe him. Whether by nature or by experience, explorers seem set apart. They are different.
If this is so, what makes them different? Is it their endurance of risk? Among modern day explorers and adventurers, astronauts experience the most risk. As they enter their spacecraft, they know that they have a one to two percent chance of not coming back. This is a much higher risk than piloting a commercial plane, hand gliding, or bungee jumping. Still, it is not beyond other earthly perils. Most astronauts only make one or two flights into space. Seen as a cumulative risk over the course of their careers, astronauts endure about the same odds of death as loggers and fishermen. Yet the dangers of exploding space craft, sinking ships, and falling trees are dwarfed by the perils of getting old, perhaps the riskiest human activity of all. Being 80 years old for six months carries with it twice the risk of death of suiting up for a flight on the space shuttle. If we value risk as a measure of mettle, then, we should be looking to verandas and nursing homes rather than the void of space.
This comparison falls short because it ignores the question of motive. Risk attends many things. We need to work. We cannot help getting old. But explorers and adventurers choose risk over safer pursuits, accept danger in their quest for something else. If risk, by itself, signifies little, risk freely accepted represents a conscious commitment. Yet commitment to what? Historically, explorers have offered many motives. The Arctic explorers of the International Polar Year (1882-1883) spoke of their desire to advance science. Henry Morton Stanley, David Livingstone, and Richard Burton all pursued geographical discovery, suffering malarial fevers in their quest to find the source of the Nile. The Mercury Seven, who strapped themselves to the top of Atlas rockets, spoke of their commitment to patriotism, competing with the Soviet cosmonauts for the dominance of space.
Yet these are not the only motives that draw people to the extreme. For many, the goal of the journey is risk itself. Danger is not the cost of admission, but the feature attraction. Free-solo climbing, BASE jumping, and wingsuit flying are activities that do little to advance science, geography, or national pride. Yet for disciples of these sports, these activities offer the promise of exploring inner worlds: survey expeditions to map the contours of fear, endurance, and self-control. Risk is the object of these missions, the means of expanding consciousness, the catalyst of self-knowledge. If explorers and adventurers are unique, then, it is difficult to pinpoint exactly what makes them unique. They are a diverse group, drawn to extreme experience for different reasons.
It has always been this way. The oldest stories in human history — Exodus, Gilgamesh, and The Odyssey — are travel epics, stories of knowledge gained through hardship. Yet the nature of this knowledge has always been mixed, the lessons of the voyage open to multiple interpretations. If the extreme is an oracle that offers wisdom, it is one that speaks in riddles. Does the journey give us knowledge about the world, as the work of Pliny, John Mandeville, and Marco Polo suggest? Or does it function, as Plato, Siddhārtha Gautama, and St Francis seemed to think, as a way of gaining knowledge about oneself? In practice, these two motives for travel – worldly knowledge and self-knowledge – were never mutually exclusive. Three thousand years of travel literature have combined elements of both.
Yet by the 1800s, the idea of travel started to fray and come apart. Those who identified themselves as travelers could be grouped into a large category that encompassed every itinerant from Joseph Banks, science officer of the Endeavour, to British lads on vacation. As the concept of traveler lost definition in the eighteenth century, “explorer” entered the vernacular to delineate it, to distinguish the extreme traveler and scientific investigator from more quotidian voyagers, the doe-eyed ingénues of the Grand Tour. At the same time, artists of the Romantic Period, who worshipped nature as an untamable force, identified the essence of extreme travel, the force which pulled travelers towards waterfalls, cliffs, and active volcanoes. They called it “the Sublime.”
Our ideas about the extreme were forged in this historical moment. Since the 19th century, we have expected our explorers to be researchers, to bring back specimens and samples. Yet in truth, we pay little attention to their scientific work. (For example, can you name one scientific discovery made by astronauts on the moon?). Instead, we marvel at the experience of their journeys, their perilous escapes. We read books about Shackleton, the explosion on Apollo 13, and Armstrong’s first steps on the moon. We remain conflicted about the meaning of the extreme. We expect our astronauts to be astrophysicists, but we want to them to speak to us like Major Tom. Through their eyes, we see other worlds too.
Our attempts to define the limits of the extreme will always be fraught; not merely because the diversity of motives which draw people towards it, but because of our own mixed feelings about what it means. We read books about polar explorers, attend IMAX films about disasters on Mt. Everest. We watch YouTube videos about skydivers, cave divers, and BASE jumpers. We do this, not because we seek to place these people in a special category, but because we feel drawn to this category ourselves. We imagine ourselves on the razor’s edge, on the lip of the abyss, at the boundary of life and death, and marvel at it. Sitting in beach chairs near the life guard tower, we recognize the absurdity of our condition, reading Into Thin Air as we apply SPF 50 sunscreen, projecting ourselves on the slopes of Everest as we eat gluten-free snacks. We do so in spite of the incongruity between the lives we live and the lives we imagine. We suffer these ironies because the explorer still speaks to us. We read, we watch, and in doing this, we feel more alive.
“Beyond the Extreme” was originally published in the online arts journal Drunken Boat, volume 16, available here.