Catastrophe: An Investigation Into the Origins of the Modern World

by David Keys

  The demographic consequences of this agricultural practice were spectacular in the extreme—especially when combined with other key religious and social changes directly or indirectly generated by the great drought and the agricultural boom that followed it. The population increased further, both as a result of improved nutrition and infant survival rates and also probably through immigration. Agricultural prosperity may also have enabled Tiwanaku to extend its political power by supplying food and alcohol for both daily consumption and ceremonial use to existing and potential future client tribes.

  The Acapana temple to the rain/sky god was not the only great monument in Tiwanaku’s ceremonial city center. A second great pyramid, now called the Puma Punku (literally, “the gateway of the puma”), was roughly six hundred feet square but only twenty or twenty-five feet high; like the Acapana, it was fitted with a hydraulic system designed to produce replica waterfalls. Adjacent to the Acapana itself stood a 185,000-square-foot palatial complex that probably served as a temple dedicated to ancestor worship.12 Surrounded by massive ashlar and sandstone walls and entered through a monumental staircase and gateway, the complex may have been a sort of palace of the dead. Some of its rooms appear to have been decorated with a series of sculptures, probably individual portraits of high-status Tiwanaku men—perhaps past rulers and dynastic ancestors. The rooms may even have been used as a last resting place for the mummified bodies of the rulers themselves.13 Certainly mummified ancestors would have been important in ancient Tiwanaku, as they were in many other Andean civilizations, including that of the Inca, who used to “invite” their ancestral mummies to attend key state occasions and banquets. Occasionally, the living even arranged for the mummies to “visit” each other socially.

  As in all religious and political systems, symbolism was a vital ingredient in the practice of power. The ancestors conferred power, as did affinity with the gods. But the symbolic presence of conquered or client peoples in a subservient position in the sacred heart of a city also conferred substantial power on its elite.

  That is precisely what appears to have happened in a large sunken courtyard virtually at the foot of the ancestor temple’s entrance staircase. The internal walls of this sunken plaza were (and still are) decorated with hundreds of stone heads, all of different sizes and different styles—probably ancestral portraits belonging to conquered or client people who were subject to Tiwanaku.14

  The precise date of this probable “gallery of empire” is not known, but it is likely to be either roughly contemporaneous with or later than the Acapana—probably late sixth or seventh century A.D. It may well be associated with the period of colonial expansion (or later imperial consolidation) that accompanied or swiftly followed the growth of the city and the construction of its great ceremonial core.

  In a limited sense, just as Europe’s initial colonial escapades in the sixteenth century were driven by a desire for exotic goods rather than land or conquest, so too were Tiwanaku’s first steps toward empire, but whereas sixteenth-century Europeans wanted to find spices and gold for commercial gain, late-sixth- and seventh-century Tiwanakans needed maize for making beer and coca for use as a drug. Both were vital elements in Tiwanakan religious rituals and in cementing political relationships through the giving of largesse, usually in feast form. Distant colonies were therefore established to obtain the coca and maize, as well as shells, minerals, and exotic fruits and other foodstuffs. Maize may also have been used as a form of currency. Archaeologist Alan Kolata in his book The Tiwanaku: Portrait of an Andean Civilization suggests that maize provided “a storable, high value, state-controlled medium of exchange that could be used by the elite to ‘purchase’ labor from commoners.”

  Among the first areas to be colonized in the late sixth and early seventh centuries by the newly predominant Tiwanakans was the two-hundred-mile stretch of coastal plain between the river Tambo in southern Peru and the river Loa in northern Chile. Settlements were established in at least eight river valleys in that coastal zone.15 The largest colony in that region so far discovered by archaeologists—a settlement of up to two thousand people—was built in the valley of the river Moquegua in the deep south of Peru around A.D. 600.

  The possession of these coastal colonies, 150 miles west and southwest of Tiwanaku, shows that the metropolis exercised at least some control—direct or indirect—over the intervening territory. Had it not, trading and other contact with its own colonies would have been nearly impossible.

  Likewise, 150 miles east of Tiwanaku—in what is now Bolivia’s Cochabamba area—dozens of colonies were established in humid valleys among the forest-clad mountains in order to grow maize, coca, peppers, and tropical fruits. Thousands of Tiwanaku-style graves have been unearthed in the area. Again, the intervening territory must have been under Tiwanakan control in one way or another.

  Three hundred miles south of the metropolis, near the banks of Lake Poopo, South American’s largest lake after Titicaca, settlements were established to control and exploit sources of salt, sulfur, edible clays—and above all basalt, which was used to make high-quality stone artifacts, everything from mundane farm implements to monumental sculptures. In order to obtain large quantities of the best rock, Tiwanakan engineers and miners had to create several miles of spectacular underground galleries. It’s not clear whether the mines (at Qeremita, fifteen miles west of the lake) were started by Tiwanakan colonists or by local tribes before the colonists arrived, but it is certain that the gallery system was at the very least massively extended and expanded by Tiwanaku. Today the Lake Poopo and Lake Titicaca/Tiwanaku areas are linked by the Pan-American Highway. But in the first millennium A.D., mining-derived products—tools and sculptures (some weighing up to half a ton)—would have had to be transported 250 miles along the Desaquadero River.

  The mining complex is probably South America’s least-known major archaeological site. Indeed, the scale of its association with Tiwanaku was discovered only in the 1960s by Bolivian archaeologist Carlos Ponce. More recently scientists, using a high-tech method called neutron activation analysis, have matched basalt objects from Tiwanaku with rocks from Qeremita.16

  Qeremita was already 250 miles south-southwest of Tiwanaku, but the city’s most distant colonies were established—probably as trading stations—hundreds of miles beyond even these remote mines. Some 570 miles south-southwest of the metropolis, a Tiwanakan presence of some sort was established in what is now Argentina at Quebrada de Humahuaca, the heart of a region rich in agricultural and mineral resources including copper, silver, gold, obsidian, and basalt. And 350 miles west of Quebrada—in the middle of one of the driest deserts on earth, the Atacama—a trading-station colony was established to exploit and/or trade in such exotic goods as lapis lazuli, crystals, and turquoise.

  The Tiwanakan empire lasted for at least six hundred years, ultimately collapsing in circumstances that were in some ways not dissimilar to those in which it was born. Climatic problems again changed Andean history in the eleventh and twelfth centuries A.D., when a particularly lengthy dry period (lasting around 250 years) destabilized the region’s geopolitics and humbled Tiwanaku.

  The “Stone at the Center of the Cosmos” may have had a diminished political influence by that time, but in religious terms it was far from being unimportant. The site retained its spiritual significance, and its traditions and gods continued to affect subsequent Andean history, including, in many ways, the much-later Inca empire.

  Just as Huari tradition had helped shape military and administrative aspects of the Inca empire (see Chapter 28), so Tiwanaku’s religious legacy helped shape the Incas’ ideological inheritance. Indeed, beneath the veneer of Christianity, ancient Andean religion still survives to a considerable extent among the sixteen million Indians of Peru and Bolivia.

  PART NINE

  THE REASONS

  WHY

  30

  I N S E A R C H O F

  A C U L P R I T

  “There was a sign from
the sun, the like of which had never been seen and reported before. The sun became dark and its darkness lasted for 18 months. Each day, it shone for about four hours, and still this light was only a feeble shadow. Everyone declared that the sun would never recover its full light again.”1

  A sixth-century historian and prominent church leader, John of Ephesus, wrote these words describing the apparent fate of our planet’s star in the years 535 and 536. And, as already mentioned at the very beginning of this book, the Roman historian Procopius also described the apparently bizarre behavior of the sun at this exact time. He regarded it as a very bad omen indeed—a sentiment that was to prove only too correct. “And it came about during this year that a most dread portent took place,” he wrote. “For the sun gave forth its light without brightness like the moon during this whole year, and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear, nor such as it is accustomed to shed.”2

  Other, similar accounts were provided by writers across the globe: in the Mediterranean region, in East Asia, in western Europe. And as we have seen in much detail in the preceding chapters, tree-ring, ice-core, and archaeological data all confirm that the mid–sixth century was a time of extraordinarily adverse climatic conditions. But what caused it?

  The suddenness with which climatic catastrophe overtook both hemispheres of the world in this period and the apparent dimming of the sun in the initial stages of the disaster point inexorably toward a causal event that hurled vast quantities of pollution into the atmosphere. In effect, the mid-sixth-century climatic experience was the natural equivalent of what scientists fear would befall the world’s climate in the event of nuclear war—the so-called nuclear winter, when nuclear-weapon explosions would force vast quantities of pulverized debris, dust, and temporarily vaporized earth up into the atmosphere. There this material would form a barrier preventing much of the sun’s light and heat from reaching the ground. Temperatures would fall, the world’s climate system would be thrown into chaos, and famine, followed by epidemics, would begin to rage.

  There are three possible natural causes of this type of phenomenon: an asteroid impact, a comet impact, or a volcanic eruption.3

  OPTION ONE: AN ASTEROID IMPACT

  The climatic effects produced by the 535–536 event—including the apparent dimming of the sun—are, in theory at least, consistent with a collision between the earth and a small asteroid of around 2.5 miles in diameter. On average, asteroid impacts of that scale occur on earth every fifty million years or so.

  The last known occasion on which a cosmic object of this approximate size is known to have hit the earth was fifty-two million years ago—and the only reason the scientific world knows about it is because the crater still survives, buried beneath 1,600 feet of later sedimentary rocks and more than 300 feet of ocean. Located off the coast of Nova Scotia, the crater is just over 25 miles in diameter, and an estimated 1,650 feet deep from the crater’s lip to its lowest point.

  Of course, no humans were around at the time to write down accounts of the experience. However, using modern knowledge of astronomy and physics, it is possible to reconstruct what happened then—and what would also have happened in 535 if indeed the worldwide catastrophe was caused by an asteroid impact.

  There are in the solar system literally tens of millions of asteroids—including about a million that are more than a half mile in diameter.4 Contrary to popular belief, they are not the sad remnants of some broken-up planet but are instead left-over building blocks from which planets were never formed. Once, 4.5 billion years ago, the entire solar system consisted of billions of asteroids; by 3.5 billion years ago, most of them had coalesced, through gravity, to form the major planets. Asteroids with a diameter of 2.5 miles are therefore really protoplanets.

  Most asteroids circle the sun in elliptical orbits that usually stay between the orbits of the planets Mars and Jupiter. Occasionally, however, a sizable asteroid crosses the earth’s orbit; even more rarely, one actually hits our planet.

  There exist around 60 asteroids with diameters of approximately 2.5 miles that cross the orbit of planet Earth. Fifty-two million years ago (and potentially, therefore, in 535 A.D.) a notional skilled observer would first have been able to sight the approaching asteroid some fifty-four hours before impact. But at 1.5 million miles from the earth, it would have been nothing more than a barely noticeable speck of light in the night sky.

  Only an hour before impact would our observer have noticed anything strange. By then, at thirty thousand miles’ distance, its shape would have been just discernible as more than simply a point of light. Half an hour later, barely thirty minutes before impact, the asteroid, now just fifteen thousand miles away, would have been the brightest object in the night sky, apart from the moon, and would even have been visible in daylight. At that stage it would have been brighter than Venus.

  Then, six minutes before impact—still twenty-seven hundred miles away—it would have been thirty times brighter than Venus and would have appeared to be a tenth of the moon’s diameter.

  Now, with the asteroid plunging toward Earth, its apparent brightness would have increased almost ninefold within four minutes, so that two minutes before zero hour, it would have been 250 times brighter than Venus, with an apparent diameter equivalent to a quarter of the moon’s.

  Then, just eight seconds from impact, this invader from outer space would have hit the earth’s atmosphere—and for the first time would have produced its own light both directly and indirectly.

  For just a few seconds prior to collision it would have become the brightest object in the sky. Observers three hundred miles away would have seen a fireball as bright as the sun. Observers thirty miles away would have witnessed a brief aerial light show a hundred times brighter than the sun.

  Most likely coming in at an angle of between 30 and 60 degrees, and at a speed of forty thousand miles per hour (having been accelerated some 25 percent by Earth’s gravity), the asteroid’s surface would have been hotter than the surface of the sun (nearly 11,000 degrees Fahrenheit).

  But that would not have been the main source of the light. Most of that would have been generated by the trillions of air molecules through which the asteroid passed. Through friction, some of the vast kinetic energy of the asteroid would have heated the air molecules to a blistering 45,000–55,000 degrees Fahrenheit!

  If the 535 event was caused by an asteroid, it would certainly have had to be a deep-ocean impact. First of all, a land impact would have created an enormous crater, which, because it would have been formed relatively recently, would be known to the geological world. No recent craters of such large dimensions exist on land.

  What’s more, in order for the dimming of the sun to have lasted twelve to eighteen months and for the climatic events to have lasted so many years, something finer than normal dust had to have been hurled into the atmosphere. Most ordinary dust would have fallen out of the sky too quickly to generate such medium- and longer-term effects. Volcanoes can achieve this by forcing huge quantities of sulfur into the stratosphere, which become sulfuric acid aerosols, capable of staying aloft and directly changing weather for several years.

  But asteroids don’t generate much sulfur. So what could such an impact do to the atmosphere that would produce those long-lasting sun-dimming and other climatic phenomena? The answer lies not in the asteroid itself but in the medium it lands in. If it hit ocean, huge quantities of water—both vaporized and in liquid form—would have been injected directly into the stratosphere. This water would have formed rapidly into high-altitude stratospheric clouds of tiny ice crystals, which would in turn have restricted and scattered the sun’s beams, creating an apparently dimmed sun, a drop in temperature, and a lot of climatic repercussions over a considerable period.

  If the 535 event was asteroid-caused, with an ocean impact, the cosmic rock—all hundred billion tons of it—would have vaporized within a quarter of a second on impact with the water and the ocean floor. Pe
rhaps 10 percent of the asteroid’s kinetic energy—around twenty quadrillion joules’ worth of it (equivalent to a five-million-megaton nuclear explosion)—would then have been transferred to the surrounding ocean in the form of heat and water movement. (Five million megatons is equivalent to a hundred thousand of the largest nuclear bombs.)

  One hundred cubic miles of water would have been vaporized almost instantly, generating 140,000 cubic miles of water vapor, which would have exploded skyward at more than twenty thousand miles per hour, rapidly penetrating the stratosphere. And around the vaporized impact site, a huge wave—between fifteen and twenty miles in height—would have reared up out of the ocean, driven by the shock wave created by the impact. Like the high-speed vapor stream, the top part of the wave would have penetrated the stratosphere.

  Moving outward at around a thousand miles per hour, the wave would have gradually lost height, so that five hundred miles from the impact site, it would have been only two hundred feet high.

  OPTION TWO: A COMET IMPACT

  Just as an asteroid collision with Earth would have produced mid-sixth-century-style climatic mayhem, a comet would have had much the same effect. But because comets are less dense than asteroids, yet normally travel faster, an equivalent energy release on impact would have required a comet nucleus with a diameter of about four miles. And although there are millions more comets traveling around the sun than there are asteroids, comets hit the earth ten times less often than asteroids do, mainly because comets normally come nowhere near our planet.