Space Archaeologist Sarah Parcak Uses Satellites to Uncover Ancient Egyptian Ruins
The Indiana Jones of low Earth orbit harnesses 21st-century technology to uncover long-buried treasures
Sarah Parcak is an Egyptologist, but her lab is more Silicon Valley than Valley of the Kings: sleek desks, beanbag chairs, bountiful snacks and a row of computer screens that, even after 9 on a Monday morning, still exhibit glassy black stares. In air-conditioned downtown Birmingham, there is no need to rise at 4 a.m. to beat the punishing Nile Delta sun. Nor is it likely that anyone working here will inhale dangerous bat dung spores, or contract a nasty parasite while transecting flooded rice fields, or face a tombside run-in with a rabid dog. In this cool, quiet room, where some of the most exciting modern explorations of the ancient world are underway, the closest thing to a historic artifact is Parcak’s fat laptop, which she hasn’t had time to replace in the last seven years.
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“Everybody makes fun of me because it’s a beast,” she says as the machine sputters and churns. “But it still works, and everything is on here.”
And she means everything.
Exploiting subtle and, to the naked eye, often invisible differences in topog-raphy, geology and plant life, Parcak, a 38-year-old University of Alabama at Birmingham professor of anthropology, has used satellite imagery and other remote sensing tools to expose a stunning array of forgotten sites from multiple lost cultures. In Egypt, her specialty area, she and her team have expanded the civilization’s known scope, spotting more than 3,000 ancient settlements, more than a dozen pyramids and over a thousand lost tombs, and uncovered the city grid of Tanis, of Raiders of the Lost Ark fame. After the Arab Spring, in 2011, she created, via satellite, a first-of-its-kind countrywide looting map, documenting how plundered tombs first appeared as little black pimples on the landscape and then spread like a rash. She has pointed out the ruins of an amphitheater at the Roman harbor of Portus to archaeologists who had spent their whole careers digging above it, mapped the ancient Dacian capital of what is now Romania, and—using hyperspectral camera data—aided in the ongoing search for prehistoric hominid fossils in eroded Kenyan lake beds.
This year alone, her satellite images revealed, in desolate Newfoundland, what many believe to be the second-known Viking site in North America, as well as a mammoth ceremonial platform in Petra that millions of visitors to the famous Jordanian city, not a few of them professional excavators, completely missed. She is now busy satellite-mapping the whole of Peru for a crowd-sourcing project called GlobalXplorer, set to debut in early 2017, that may yield her most audacious set of revelations yet. Meanwhile, she continues to happen upon new finds, sometimes while idly thumbing through Google Earth on her iPhone at the airport.
In a discipline where discovery is traditionally confined to a two-meter-square excavation pit, Parcak treats the heavens as her trenches, sieving pixels like sand. “Sarah is doing this on a scale bigger than anybody else,” says Patty Gerstenblith, director of DePaul University’s Center for Art, Museum and Cultural Heritage Law.
In the lab, Parcak’s ancient computer finally regains consciousness, and she grins, shoving back sand-colored hair. I wonder which fancy new data set we’ll see first. But instead she’s calling up on the screen a hand-drawn Napoleonic map of the Nile, albeit in digitized form. “It’s kind of like French Google Earth from 200 years ago,” she says. She points out a “village ruiné” that has caught her eye: She hopes the image will lead her closer to the city of Itjtawy, the lost capital of Middle Kingdom Egypt.
“It doesn’t matter how modern our images are,” she explains. “We always go back to every map that’s ever been made, because they contain information that no longer exists.” Only after scrutinizing local architecture and landscape changes over millennia will she study data-rich satellite images that reveal latent terrestrial clues. She’s already used NASA radar to locate a wealthy suburb of Itjtawy, a find she has confirmed on the ground by analyzing soil samples that reveal bits of worked amethyst and other valued stones. Along with cross-referencing colonial-era surveys, the next step is to layer satellite images to make a 3-D topographical map of the area, which might indicate where the ancients chose to build on rises in the ground, to escape Nile flooding.
“People think I’m Harry Potter, and I wave a wand over an image and something appears and it looks easy,” she says. “Any discovery in remote sensing rests on hundreds of hours of deep, deep study. Before looking at satellite imagery of a cemetery or a pyramid field, you have to already understand why something should be there.”
Compared with her minimalist lab, Parcak’s Birmingham home, which she shares with her husband, an archaeologist named Gregory Mumford, is much more the stereotypical Egyptologist’s lair, piled with jackal statuettes and papyri and, incongruously, a model ruin of a medieval stone castle (actually her 4-year-old son’s Playmobil set). Among her favorite touches is a framed antique Sphinx sketch. In this artist’s interpretation, the Sphinx’s eyes are not stony and unseeing but bright and inquisitive and almost alarmed, as though glimpsing something startling from way up there. Archaeologists have long pined for a bird’s-eye view like this, deploying hot air balloons, kites, helicopters, powered parachutes and blimps to snap pictures of their sites. But, until recently, satellite images were not sharp enough to reveal the small features these researchers sought, like mud brick walls.
Parcak always assumed that she would find mummies the old-fashioned way—by descending into the earth, not orbiting by satellite some 450 miles above. She had her first tomb dream when she was about 5, which was peculiar, because no mummy inhabits her hometown of Bangor, Maine. “I wasn’t taken to a museum,” says this daughter of restaurateurs turned social workers. “Apparently I just started talking about Egypt.”
At Yale University, Parcak studied Egyptology and archaeology and embarked on her first of many Egyptian digs. But in her final year she spied a class on “remote sensing,” the study of the earth from afar. Parcak’s Yale professor warned that an archaeology student would flounder in his course, which was a tangle of algorithms, electromagnetic spectrum analyses and software programs. Parcak bombed the midterm. Toward the end of a semester of despair and stubborn cramming, though, came a moment of clarity: The whole field popped into view, like the base of an excavated pyramid. Parcak realized that her home turf of Egypt, because it’s an area of major Western government surveillance interest, offered some of the richest available satellite data on the planet. “All of a sudden,” she says, “I understood remote sensing.”
Today she toggles between cutting-edge satellite data and classic fieldwork. Often she’ll start with an open-access source like Google Earth to get a sense of the landscape, then zero in on a small area and, for a few hundred to several thousand dollars, purchase additional images from a private satellite company called DigitalGlobe. To show me a key procedure, she yanks out her iPhone and scrolls up the western European shoreline. “We are a looooong way from Egypt,” she says. A few years ago, after consulting with Norse specialists and studying Viking architecture, Parcak began to scrutinize a farmer’s plot in Papa Stour, among the remotest of Scotland’s Shetland Islands. She ordered infrared satellite imagery of the tweedy green and brown fields. After some computer processing, a bright pink line revealed itself.
Plants growing over buried structures tend to be less healthy because their root systems are stunted. These differences in vigor are seldom apparent in visible light, the narrow part of the electromagnetic spectrum that the human eye can see: To humans, plants tend to look evenly green. But certain satellites record the infrared wavelengths reflected by the plant’s chlorophyll. Using false colors and software programs, Parcak tweaks these differences until the healthy plants look redder on screen, and sicker ones appear pink. Excavating near the fuchsia dash of less robust vegetation, Parcak and her colleagues unearthed a stout Viking wall, soapstone bowls and a faceted carnelian bead. These same spectral patterns helped focus Parcak’s search for the possible Viking site in Newfoundland, where she later dredged up the apparent remains of a hearth and some 20 pounds of roasted bog iron, a good indicator of Viking iron-making.
And because Parcak frequently works in deserts, she is constantly tweaking her methods for areas where it’s not always possible to probe plant life. Her remote imagery can expose moisture differences in surfaces above buried mud bricks, eerily revealing foundations of vanished buildings. In other climates, frost lines may highlight ruins, or chemicals from shell middens or certain types of stone may bleed into the surrounding soil, offering a telltale spectral signature.
“A lot of us looking at one of these images would say, ‘Nice desert!’” says Eric Cline, an archaeologist at George Washington University. “But then Sarah hits a button and all of a sudden there’s a city right there. She is an artist as well as an archaeologist, because it is an artist’s job to interpret these things.”
Parcak often confirms discoveries made at her desk by visiting previously unseen sites and coring the earth or otherwise scouting for artifacts, a process called “ground truthing.” Her hit rate in the field is near 100 percent. “When I was a little kid,” she says, “you could show me a patch of three-leaf clover, and I would find the four-leaf clover.”
-- Sent from my Linux system.