Archaeology from Space Read online

  Until then, we should ask what ancient features satellites can reveal. Pyramids and temples are amazing things to discover, from the air or on the ground. Those features are rare, though, and represent a tiny fraction of what archaeologists find. We are far more likely to dig up a wall, or a room in a small house. It may seem less glamorous, but trust me, those are the findings that inform history, over time. And, as it turns out, satellites are just the thing to help find them.

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  The Promise of Space Archaeology

  Archaeology invites visions of the mysterious and unknown, fueling common misconceptions about ancient societies. Most of the time, rediscovered “lost cities” and intact tombs make global headlines, but that does not mean archaeologists hack through rainforests to help entire Maya cities emerge from the dense vegetation, perfectly preserved. If only that were true! It’d save us all a lot of time and effort.

  Cities rise and fall. Their buildings, whether temples, administrative complexes, workshops, or houses, can collapse from natural disasters or human violence, have their stones repurposed by later cultures, and slowly succumb to Mother Nature once abandoned. Discovering a city is only the beginning. Archaeologists want to know who built it in the first place, who lived there, and where its lost inhabitants went. The real gift is the opportunity to search for those answers.

  Complex answers to archaeological questions do not make clickbait headlines, but real archaeology doesn’t have to be far-fetched to be fascinating. Consider that in most post-apocalyptic movies, you see hordes of bad guys wearing leather, riding motorcycles, armed to the teeth, and living in bad-guy strongholds. I always wonder where their underlying support system is and ask about the thousands of people tanning their clothing, processing the fuel for their vehicles, and working in the fields to feed them.

  Whenever a major discovery is announced, archaeologists see implications about the culture’s people—farmers, stonemasons, artists—and its ecosystem as a whole. The media remains focused on the one tomb, the one religious site, or whatever the find happens to be. Alongside the media, museum curators probably carry some responsibility, when they put together displays designed to draw big crowds.

  One such blockbuster exhibit toured the United States years ago, on the objects of everyday life found at Pompeii. Here’s what I remember from my visit: dismay and disappointment. Instead of the everyday implements that I had hoped to see, the ones that make my heart go pitter-patter, I saw gold. And more gold. And yes, more gold. I’d say jewelry represented 80 percent of the objects on display. This exhibit toured the country and attracted hundreds of thousands of visitors, and the curators missed an opportunity to educate the public on how we interpret the past.

  And frankly, the people I saw there had far greater interest in the everyday objects on display, because they could connect them to their own lives. Admittedly, we could see where archaeologists had found all that jewelry and associate wealth with the corresponding individuals or houses. But wealth doesn’t portray the richness of society any more than crazies in dune buggies fully represent post-apocalyptic survival. All that the Pompeii exhibit reinforced was the idea that archaeology deals mainly with shiny things and that those things have more value than a pair of tweezers or a carbonized loaf of bread.

  Calculating the Importance of Discoveries

  Like those everyday objects, 10 “small” discoveries appearing in minor journals can impact a specific archaeological field far more than any headline-worthy discovery. Now, I’m not saying that blockbusters or headline-worthy archaeology aren’t awesome, important, or groundbreaking. Headlines fill our classes, remind people why archaeology is cool, and help justify government support. However, let me help put the discovery of a single intact Egyptian tomb in perspective.

  Pharaonic civilization lasted 2,700 years, from the unification of Egypt in 3000 BC to the Ptolemaic Period, which ended in 30 AD with the death of Cleopatra.1 Tombs of elite figures, the type that make headlines, including those for artisans, high-ranking officials, and royal family members, appeared with more frequency during periods of greater stability. You might expect to find well-provisioned tombs from the Old Kingdom (2700–2200 BC), the Middle Kingdom (2000–1700 BC), the New Kingdom (1550–1000 BC), and the Late–Ptolemaic Periods (600 BC–30 AD). Thus, we have 1,800 years or so when we might find richer tombs.

  Population estimates of ancient Egypt vary from 3 million during the Old Kingdom, to 4.5 million during the Roman Period (30–641 AD). Since this is hypothetical, let’s stick with the lower estimate. Of those 3 million people, that newsworthy elite formed the uppermost 1 percent. So, for every generation, say, roughly 40 years, since the rich generally lived longer, we can expect to find 30,000 tombs that would raise eyebrows today.

  Now we follow through with the math.

  Over 1,800 years, 45 generations lived and died, with the top 1 percent constructing 1.35 million elite tombs. In the 200-year history of Egyptology, at most, Egyptologists have discovered approximately 13,500 elite tombs—that’s just 1 percent of that 1.35 million total.

  Consequently, when an announcement is made about a spectacular new tomb, keep a cool head and look for its contribution to our larger understanding of ancient civilization.

  I’m not saying I’m immune to our societal obsession with shiny things. A flash of gold fires everyone’s wilder archaeological fantasies. Having just returned from a third excavation season at Egypt’s Middle Kingdom capital, modern-day Lisht (which you’ll hear more about in later chapters), I had the good fortune of finding gold leaf fragments, and even a dense chunk of gold, that came up from an intrusive tomb to the north of the main burial complex. It had heft, and I spent way longer than I should have staring at it. If unrolled, the fragment would probably cover an area of two US quarters put together; it was not exactly the same as Howard Carter peering into Tutankhamun’s tomb for the first time. But in the midst of 17-hour workdays, managing a large team, 5,000 miles away from my son, I needed a shiny hit to perk me up. We all do, sometimes.

  Fact, Not Truth

  The purpose of archaeology is, to quote Indiana Jones, “… the search for fact, not truth. If it’s truth you’re interested in, Dr. Tyree’s philosophy class is right down the hall.” The field has evolved in the past century from one focused on things to one focused on the people behind the things, and the forces that drove people to change. Or not to change.

  Most archaeologists would tell you we frame research questions or formulate hypotheses, and then develop strategies to answer and test them. We certainly try to tell the truth, at least in our articles.

  Every archaeological field rests on some basic assumptions. For example, ancient Egypt became unified around 3000 BC, and someone wrote the last hieroglyphic inscription discovered so far in 394 AD. We know the general order of kings, and we know something about their family trees, the names of their capital cities, and who built what and when. The framework of our Egyptological tapestry survives.

  Much of the weft is, unfortunately, missing. Enough of the design remains for us to generalize, and parts are quite clear, but finding the missing threads, and figuring out how we should weave them back together, is not easy.

  The story of everyday past people, across the globe, is only now better understood thanks to applying new scientific methods to archaeology. No less than remote sensing, archaeological science was itself new in the 1960s. Now, we can examine past diseases using DNA and bone analyses,2 and we can learn what people ate through chemical residues on utensils and pots.3 Innovations in archaeological dating4 bring a clearer view of chronology.

  From these microscopic fragments of thread, the bigger patterns can be extrapolated. I can speak about Bronze Age collapse, across the Near East and Mediterranean around 1177 BC, only by drawing data from hundreds of sites, osteoarchaeological analysis of thousands of individuals, tens of thousands of lab samples, and hundreds of thousands of collective hours spent in the field.5 Archaeological analys
is can be reached only by tiptoeing across the shoulders of swaths of scientific giants.

  You have to learn this knowledge assembly young. Because I am an annoying professor who likes to make her students think, I assigned an exercise to my Archaeological Theory class, composed mainly of upper-year anthropology majors, using something I had found in the Metropolitan Museum of Art’s online catalogue.6 It was a square, pinkish ceramic object with a pinched nose and two holes for eyes that looked a lot like my son’s kindergarten art projects. I asked my students for information about its cultural context, manufacture, and function. We rarely work on sites where no previous information exists about that culture or time period, but I challenged my students to start from a place of ignorance. Formulating thoughts and ideas about the piece without any additional information proved a large hurdle for them.

  No two papers were identical. Some defaulted to the traditional object interpretation that archaeologists offer when we have no clue: “cultic or ritual in nature,” with accompanying ideas of just how the culture used it. Each student used the entirety of their archaeological knowledge to interpret the piece; I was fascinated by their responses and impressed with their creativity. One student even hacked the system, putting the object into Google’s image search program (outsmarted again!), and one student knew already.

  Once they learned what the object represented—an execration piece, buried by individuals to defeat their enemies magically—they had a lot of questions, starting with, “How could we ever have guessed?” Ah grasshopper, you get the point! To know anything about the function of an object requires so much more than the object in isolation, which is why a dig team pools such varied expertise.

  How a Dig Works

  Every time you go into the field, you risk your reputation, and even your life. You are typically using someone else’s money and a whole lot of other people’s time, and you have probably spent years preparing your research and applying for funding. Not only that, but you may be navigating another country with associated cultural and linguistic challenges.

  Once in the field, as a dig director, you are responsible for the team of specialists there to record the site and its specific data. Each supervising archaeologist takes copious notes and samples from every layer or area dug, typically called a locus, treating each as a distinct 3-D time capsule and recording details about its soil, color, density, material culture, bones, and anything else.7

  Site supervisors are only the first contributors in the process of extracting archaeological data. Bioarchaeologists analyze human remains, paleobotanists look at preserved plant fragments, artists draw and interpret objects, and cataloguing and documenting finds is the job of registrars and photographers.8 I have come to believe that ceramists are your most important people.9 They draw, record, and analyze pottery, and on most historic sites, potsherds beyond number represent the Tupperware of the ancient world. How and why pottery changed over time can be your best insights into the past.

  Many others may also join the team, but a spread of specialists like this makes up the core unit on most digs. Ideally, a dig runs like clockwork, with everyone working toward a common goal so you can write articles about the findings, apply for more funding, and do it all again. Another thread gets added to the tapestry … if all goes well.

  You can imagine maniacal laughter here, because I’ve been on digs all over the world, and absolutely any challenge imaginable can and does arise. The public never sees this side of excavations—you only see the object in the archaeologist’s hand in the perfectly lit glossy magazine photo. Colleagues tell me stories from the field that I would not believe had similar things not happened to me. When our team worked in Sinai in 2004, I came back to the site after breakfast one day to find that our site drawings had become the midmorning snack of a goat from the nearby town. He ran away, and I tackled him, saving about 70 percent of the plans. It took us hours to redraw everything. At the season’s end, we had a feast, courtesy of our lovely Bedouin workforce, and the pièce de résistance was roasted goat. No points for guessing which one. I chewed with great relish.

  Context Is Everything

  If the goat had munched the lot, it would have been a disaster. We have one shot to record every possible fragment of meaning, for to dig is to destroy; once you have excavated a level, or a whole site, it is gone forever. When archaeologists uncover an object, they record its exact location to give context relating to everything else found on that site and other sites like it. For example, finding burned pots next to a flat area that has a stone oven and is covered in plant debris and seeds might indicate an ancient kitchen. If we miss things, or worse, if the site is looted and the pot surfaces for sale, all we can say about it is that it is a “blackened pot.”

  Archaeological sites are, occasionally, just like a box of chocolates: you genuinely never know what you are going to get. It is what makes our work so exciting. When archaeologists know little to nothing about a site, we make assumptions based on other similar sites in the region. Sometimes we get it right, but often, we are spectacularly wrong. The irony is that the ingrained awareness of just how wrong we are likely to be is what drives us ahead. Applications to the grant review committees sometimes couch everything we think is there as “maybe,” “potential,” and “likely,” when we perhaps ought to write, “I haven’t the faintest idea, so send us there anyway to find out.”

  What is at stake is nothing less than the sum total of human history and knowledge. No pressure.

  To limit needless destruction during excavation, and to keep our work on time and within budget, we dig in the most focused way we possibly can.

  If used well, space archaeology can give us a pretty good idea of structures or features at a site, or at least, just below its top layer. Being able to develop hypothesis-driven research on what is there versus what might be is game-changing.

  We can see neither potsherds nor individual occupation levels on satellite imagery. But we can see walls, entire buildings, geoglyphs like the Nazca lines,10 vanished landscapes, and relationships between site and site, and between site and landscape, in ways we could not 40 years ago, in places we would never have thought to check. With ever-improving use of the light spectrum and new programs to manipulate images, we now can highlight such features, when they would have been easily missed or altogether invisible before.

  Satellite imagery allows us to see features at varying scales, from the very small to the overwhelming, and boy, can we use the help. When we spend so much time squinting at the ground, we need some perspective.

  Traces of the Vikings

  A good place to illustrate this is an island in the North Atlantic, famous for its geysers, Vikings, gender equality, and unpronounceable volcano names. The landscape is as tough as the Vikings’ reputation: to survive in Iceland requires extraordinary strength and resilience. Starting in 871 +/-2 AD, the Vikings came to Iceland from their conquest of Scotland’s Western Isles to build farms, though whether people lived there prior to 871 is controversial. An Irish monk may have written about Iceland as early as 825, referring to possible settlers there in the late 790s.11

  Whether from a colonization mission blown off course, or people brought to Iceland by Scandinavian Vikings as slaves, farming communities expanded across Iceland quickly.12 The Book of Settlements, also known as the Landnámabók, records a genealogy of the first 430 Viking settlers of Iceland.13 From that meticulous Viking start, Icelanders are still obsessed with their genealogies:14 for any concerned Icelanders, there is even a dating app to ensure they don’t end up in bed with a close cousin.15

  You can forgive me for thinking, as an Egyptologist, that I would never in a million years have any reason to work in Iceland. There are fairies,16 not pharaohs, and the only pyramids you’d find would be those made of snow in sculpture competitions. I do like a challenge, and life is strange, but I still never expected my work to lead me across the North Atlantic.

  Small Farms, Big Farms, and Viking C
olonization

  The Skagafjörður Church and Settlement Survey is a collaborative archaeological project between the Skagafjörður Heritage Museum and the Fiske Center at the University of Massachusetts Boston.

  Led by a handsomely bearded archaeologist named Doug Bolender—who would not have seemed out of place in Iceland 1,000 years ago, save for his extreme politeness—the project focuses on Iceland’s 9th-century colonization and later development, and how it may have affected the performance of religious and economic units in the 14th century.

  I met Doug during the research phase of a BBC TV program I was involved in about Vikings.17 He and his team, using ground-based remote sensing18 and coring, were pushing the boundaries of Icelandic landscape archaeology, and he was keen for a collaboration using satellite imagery.

  We know a great deal about early Icelandic history because of the famous and very well-preserved medieval sagas.19 You can see them on display in Reykjavík, in the aptly named Settlement Exhibition Reykjavík 871 +/-2, where visitors can walk around a real Viking longhouse and see amazing holographic videos of daily life in early Iceland.20

  Map showing location of Skagafjörður in northern Iceland [MAP COURTESY CHASE CHILDS]

  These reconstructions gave me a few clues as to what I might be looking for from space in northern Iceland, some 200 kilometers from Reykjavík. There, clouds seem to float right in front of you, and the sharp slopes of mountains lead to emerald-green farmland that rolls down to the edge of the ocean, as far as the eye can see.

  The early Icelanders typically built structures with cut turf, just like the strips rolled out on golf courses, readily available across the entire country. Unlike Scandinavia, where oak trees abounded for longhouse construction, Iceland had only driftwood and birch,21 used mainly for house framing, with turf for walls and roofs.22 Turf is essentially a giant, soft Lego and is very warm; I spent a lot of time petting the walls on the Viking sites I visited. On a freezing cold day, a small fire will keep a turf building quite toasty, and the Vikings used turf for their main longhouses and nearly all their farm buildings.