During his first voyage to the South Pacific, James Cook carefully charted Australia’s east coast and promptly claimed ownership of it on behalf of the British crown. Within two decades, Great Britain had established a penal colony at Sydney Cove: the Colony of New South Wales. Convicts, some in leg irons, some in chain gangs, became the workforce of British colonization across Australia. Britain wasn’t the only power interested in obtaining a precise picture of Australia’s coastline. The Dutch—seeking spices that could help fund their military operations against Spain—had already spent the previous century and a half charting the north, south, and west coasts. The French, too, explored and charted the landmasses of the South Pacific. One thing is certain, though: absent the hegemonistic agenda of the British empire builders, nobody would have measured the 1769 transit of Venus.
Before the International Meridian Conference of October 1884, and even for decades afterward, the world was in a muddle in the matter of determining time and place.
Time had long served as the marker of distance, if not place. The unit used by the ancient Greeks to measure distances on land was the “day’s journey,” on the open sea the “day’s sail.” Medieval English mariners were advised to “go south a glass or two”—that is, to sail southward for the time necessary to drain a sandglass.62 Medieval Arab navigators marked distances traveled in zams, three hours’ sailing. Even today, in a car-loving location like Los Angeles, locals will tell you that LAX is thirty minutes from the Staples Center.
Scientists turned units of time into units of angular measure: the degree divided into the minute and the second. For everyone else, units of every sort remained a local matter, subject to great variation. The distance represented by, for instance, the ancient Greek stade (the length of one footrace, which gave rise to the stadium) varied so much from region to region that it could barely serve travelers as a unit of length, and so the conquering Romans replaced it with the mile. Meanwhile, the width of a seaman’s middle finger held at arm’s reach, whether he be fat or thin, marked a span of two degrees.63
Yet place remained elusive, as did the problem of finding the longitude—indispensable when ascertaining place. From Hipparchus in the second century BC to Kepler, Galileo, Newton, and other luminaries from the sixteenth to the eighteenth centuries, nobody was able to figure out how to achieve it with precision. This involved devising a rigorous system and good instrumentation with which to measure it; choosing a widely acceptable zero point, or meridian, from which to start measuring it; and convincing everybody else to adopt both measurement and meridian. In fact, “finding the longitude” became slang for the pursuit of a task either insanely difficult or just plain absurd.64
But difficulty did not obviate necessity, and the founding of France’s Royal Academy of Sciences and the Paris Observatory during the reign of Louis XIV, and Britain’s Royal Observatory Greenwich during the reign of Charles II, had a lot to do with the need to resolve the issue. The better-known sea lanes were filling up with massive vessels, laden with cargo and cannon. Merchants were pursuing their fortunes, kings were pursuing their empires, and privateers and pirates were pursuing everyone. In the absence of a precision system of longitude, it was not only courageous but also foolhardy, greedy, and suicidal to seek new routes to new places. And so, in March 1675, a twenty-eight-year-old ordained deacon, John Flamsteed, was chosen the first Astronomer Royal of Britain and charged “forthwith to apply himself with the most exact care and diligence to rectifying the tables of motions of the heavens, and the places of the fixed stars, so as to find out the so-much desired longitude of places for the perfecting [of] the art of navigation.”65
Among the many spots used by philosophers and astronomers over the centuries to mark the meridian for zero degrees longitude were Ferro, in the Canary Islands; Ujjain, in the Indian state of Madhya Pradesh; the “agonic line” (a line along which true north and magnetic north coincide, but not forever) that passed through the Azores; the Paris Observatory; the Royal Observatory at Greenwich; the White House; and the Church of the Holy Sepulcher in Jerusalem. Among the proposed yardsticks by which to ascertain degrees east and west of zero were an eclipse of the Moon or the Sun; an eclipse of Jupiter’s four Galilean satellites; an occultation of a star by the Moon; an excellent compass, impervious to variations in terrestrial magnetism; and the joint efforts of an excellent clock, a fleet of gunships, and a fleet of vessels equipped for a sound-and-light show.66
If you relied on an astronomical event, you would consult precise and exhaustive ephemerides for a known meridian and then compare them with your own observations, performed wherever you happened to be, reckoning fifteen degrees of longitude for each hour of time difference, since twenty-four hours’ worth of fifteen degrees equals a full 360-degree turn of the Earth.
Easier said than done.
For one thing, ephemerides were still inexact. For another, you’d need a long, powerful telescope—and how would you keep such an unwieldy object unmarred by salt air, and steady on a heaving ship? Having faced these difficulties in 1764 when trying to observe Jupiter’s satellites at sea, Reverend Nevil Maskelyne, author of the British Mariner’s Guide and the first Nautical Almanac, opined, “I am afraid the complete Management of a Telescope on Shipboard will always remain among the Desiderata.”67
Surely a reliable portable timepiece would be a better solution. It would “enabl[e] mariners,” writes Dava Sobel, “to carry the home-port time with them, like a barrel of water or a side of beef.” The rub was reliability. In 1500, even a fine clock sitting firmly on solid ground would generally accumulate an error of ten or fifteen minutes with each passing day. But that didn’t faze Regnier Gemma Frisius, a Dutch mathematician who proposed that a good clock, set to the exact moment a ship left the dock, could serve as a stable point of comparison for the local time as ascertained at sea by Sun, star, or other means—assuming that the clock’s exactness could be preserved despite the moisture, cold, heat, salt, gravity, and tumult.68 Quite a task. Not until 1759, after thirty years of effort, did a provincial English craftsman named John Harrison manage to implement Gemma’s proposal.
Harrison undertook the project not out of enthusiasm for a challenge or concern for his shipwrecked countrymen but because in the summer of 1714 the British parliament had, in desperation, put up a series of substantial cash prizes for a solution to the longitude problem. Spain had been the first to offer a prize, in 1598; Portugal, Venice, and Holland had followed suit—but to no avail, which is why France and Britain soon turned to the founding of scientific academies, the building of observatories, and the luring of Europe’s name-brand astronomers, still to no avail. Throughout the seventeenth century, neither wrecks nor rewards led to longitudinal certitude. Meanwhile, empire building accelerated and maritime tragedies multiplied.
Then, in 1707, Britain suffered an especially horrible wreck: a fleet of Her Majesty’s warships under the command of Admiral Sir Cloudesley Shovell (spellings vary) foundered on the Scilly Isles, causing the loss of four vessels and the death of two thousand men. A coalition of dismayed ship’s captains, naval commanders, and London merchants soon petitioned the government to offer “due Encouragement” so that “some persons would offer themselves” to the task of “Discovery of the Longitude.” The method and mechanism were unspecified. Parliament consulted Newton, Halley, and other notable scientists, drafted the Longitude Act, and set up the Board of Longitude to vet proposals and results. The guidelines were clear: £20,000 for accuracy within a margin of error of half a degree, £15,000 for two-thirds of a degree, and £10,000 for one degree. The accuracy would be assessed on a voyage between the homeland and the West Indies aboard a British ship. Since such a voyage would take six weeks, any mechanism that lost or gained more than two minutes—the time equivalent of half a degree—over the course of the journey could not fetch the top prize.69 Sounds strict, until you consider that being off by half a degree is like heading for Times Square in the heart of Manhattan but
ending up across the Hudson River in Plainfield, New Jersey, or telling your navigator you want to go to Fort Worth, Texas, but getting dropped in Dallas.
John Harrison fashioned not just one but several chronometers, whose accuracy exceeded the most stringent demand of the Longitude Act. The first, completed in 1735 and known as H-1, was an intricate brass tabletop contrivance that ran on springs, wheels, rods, and balances; the fourth, H-4, completed in 1759, was an exquisite outsize watch that lay supine in a cushioned box and ran on diamonds and rubies. Of the latter, its maker declared, “I think I may make bold to say, that there is neither any other Mechanical or Mathematical thing in the World that is more beautiful or curious in texture than this my watch or Timekeeper for the Longitude.”70
Unswayed by H-4’s beauty, powerful members of the Board of Longitude—fervent advocates of finding the longitude by comparing the Moon’s observed angular distance from major stars with the distances listed in continually updated tables compiled by the world’s top astronomers—fought for decades against Harrison’s receiving the money and recognition that were his due. Instead they kept presenting him with dribbles of interim funding, new conditions, new insults, and eventually the outright confiscation of his creations by his most dedicated enemy: Reverend Nevil Maskelyne, a lunar-distance partisan and now Britain’s Astronomer Royal. King George III (the same monarch whose “injuries and usurpations” are enumerated in America’s Declaration of Independence) finally stepped into the fray on behalf of the elderly clockmaker in 1772, and the next year Parliament decided in his favor. Never, however, did the unrelenting Board of Longitude itself award Harrison the top prize, and never did he receive the full £20,000 to which he was entitled.71
What Harrison did receive, however, was vindication from James Cook, who carried an exact replica of H-4 on his second voyage to the Pacific, in 1772–75. As valuable to navigation as a sharp-eyed person scanning the waters from a ship’s bow, Harrison’s chronometer endowed the word “watch” with new meaning. This timepiece, wrote Cook, “exceeded the expectations of its most zealous advocate and . . . has been our faithful guide through all vicissitudes of climates.” He referred to it as “our trusty friend the Watch,” “our never failing guide, the Watch,” and asserted that “indeed our error (in Longitude) can never be great, so long as we have so good a guide as [the] Watch.”72 With its help, he crossed the Antarctic Circle, conclusively disproved the existence of a massive southern continent extending well north of Antarctica, claimed some chilly islands for Britain, and charted regions of the South Pacific so accurately that twentieth-century mariners continued to depend on his findings.
John Harrison died in 1776, but even before he was laid to rest, a skilled assistant had begun to make knock-offs of H-4: the cheaper and less functional K-2 and K-3. The race for an affordable chronometer was on. Within a decade or so, competition among chronometer designers had become almost as fierce as the original race to discover the longitude. In the service of both commerce and conquest, on behalf of the East India Company as well as the Royal Navy, ship’s captains spent their own money to buy, not just one, but often several chronometers, so that they could be cross-checked with one another. Smaller and cheaper versions of Harrison’s invention became essential equipment. The navy kept a stash at Portsmouth. In 1737 there was one lone marine timekeeper in existence; in 1815 there were about five thousand. HMS Beagle, whose task in 1831–36 was to register a circle of longitudes around the Earth, carried twenty-two chronometers—in addition to a then-unknown twenty-something naturalist named Charles Darwin.73
But until 1884 the world was unable to agree on an official Earth-wide midnight hour at which an Earth-wide day would begin at an agreed-upon place, so there was no recognized zero point from which geographic eastward and westward would originate. Preferences regarding the designation of zero degrees longitude depended more on nationality, religion, and patriotism than on the obvious utility of having a common international standard for time and place. Astronomers at the Royal Observatory Greenwich had long obtained and maintained precise data on celestial coordinates for the stars passing overhead—coordinates based on a prime meridian that traversed the site of their own telescope. Early eighteenth-century Europeans tended to use the Paris Observatory as their zero-degree reference for longitude on land; nineteenth-century Europeans tended to use the Greenwich observatory for longitude at sea.74 By the late nineteenth century, ships’ captains, railway magnates, armies, navies, astronomers, geographers, and hydrographers could wait no longer for complete consistency. Agreement had to happen.
At long last, compelled by an act of the US Congress, a conference took place in 1884 at the State Department. Twenty-five nations sent representatives. Sixteen sent diplomats rather than scientists, signaling lack of serious intent. One of the earliest resolutions had to do with whether a group of invited astronomers, representing the broad interests of science, would be free to contribute their thoughts to the discussion as they saw fit. It failed.75 After enduring the first several sessions, the reporter for the weekly journal Science complained, “The time has been mostly taken up with political diplomacy and sentiment.” An irritated British representative, Lieutenant General R. Strachey, encountering resistance to the prospect of full international agreement and precision, declared that “longitude was longitude, and as a geographer he must repudiate the idea of first-class longitudes for astronomical purposes and second or third rate geographical longitudes.” An equally irritated American representative, the astronomer Lewis Rutherfurd, pointed out that “the delegates must have studied the matter before coming here; and that no one would be likely to come unless he knew, or thought he knew, something about the matter.”76 Altogether a contentious affair—a forerunner of early twenty-first-century climate conferences.
In the end, on October 22, 1884, the assembled delegates bowed to the inevitable and acknowledged the benefits of adopting “a single prime meridian for all nations, in place of the multiplicity of initial meridians which now exist.” They agreed it would bisect the base of a very special telescope at the Greenwich observatory. Henceforth there would be a “universal” day “to begin for all the world at the moment of mean midnight of the initial meridian” and that “the astronomical and nautical days will be arranged everywhere to begin” at that same moment.77 Not until 1911, however, did France officially accede to the Greenwich-based meridian.
Far into the foreseeable future, even as the continents drift and national borders are redrawn by force or by justice, Earth’s hard-won coordinate system of latitude and longitude will persist as a frame of reference. But not for everyone and not for all purposes. One century after the International Meridian Conference of 1884, the sky-and-telescope-based Greenwich prime meridian lost its overarching authority to a more refined meridian, based on Earth’s global gravitational field and established by pulses of laser light aimed at reflective satellites. Because of the uneven distribution of mass in Earth’s crust and mantle, if you head straight down from the original prime meridian you will not intersect with the center of our planet. But if you follow the upstart, “geodetic” meridian—102 meters east of Greenwich’s traditional prime meridian—you’ll pass right through Earth’s exact center of mass.
The US Department of Defense had been working on a geodetic meridian since early in the Cold War. By the 1980s, new techniques and greater quantities of data made it possible for Earth and space scientists to agree on a viable, internationally consistent system that, having been adopted by the US Defense Mapping Agency in 1984 and incorporated into America’s GPS constellation, has become the global standard for satellite navigation and the basis for Universal Time.78 Once again, in a pattern as old as civilization, stars and bars joined hands for the sake of ever greater exactitude—exploiting each other’s needs, passively and actively achieving each other’s ends.
4
ARMING THE EYE
Unassisted seeing is a weak way to engage with the glories of
the universe. Without optical aids to bridge all those physically unbridgeable distances, we can’t come close to knowing what’s out there. Human beings need huge amounts of help just to recognize what takes place in the visible cosmos, let alone the multitudinous events happening in nonvisible bands of light.
On its own, the human eye is a good but not great detector, capable of resolving the visual data in only about one-sixtieth of one degree of a complete, 360-degree circle. With its embarrassingly narrow wavelength range of 400–700 billionths of a meter, the human retina detects a mere sliver of the electromagnetic spectrum. That sliver has been assigned a self-evident name: visible light. If you think of light as a wave traveling through space, the wavelength is simply the distance between two consecutive crests. Clock how many crests pass per second, and you get the frequency. Whatever the speed of the passing wave, the shorter the wavelength, the higher the wave’s frequency.
The full electromagnetic spectrum may extend forever in both directions: toward ever longer wavelengths, perhaps limited by the size of the universe itself, and toward ever smaller wavelengths, perhaps limited by quantum physics. Currently we have the technology to detect wavelengths ranging from less than a hundred-billionth of a meter (high-frequency gamma rays) to many hundreds of kilometers (extremely low-frequency radio waves). That’s a factor of quadrillions.
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