The Space Archaeologists

In the scattering of broccoli tops below us, Saturno, an expert in satellite imaging who typically splits his time between Boston University, the Guatemalan jungle and NASA’s Marshall Space Flight Center in Huntsville, Alabama, searches for clusters of unusually tall trees or circles of isolated species. If he can figure out what features correspond to human occupation at Lingapura, he can process satellite images so that the city’s trails pop out, allowing Evans to later identify hidden sites from his computer screen.

Saturno notices that the foliage surrounding the handful of temples not covered by trees is thriving, a promising sign. Returning to the ground, they tread a careful path to the temples; only a 30-foot-wide area around each building has been de-mined. Their first stop is a temple holding a one-ton, seven-foot-tall linga—“proof that size matters,” Evans cracks. But Saturno doesn’t respond. He’s busy examining the vegetation from a new angle. He gets excited when he spots a tall, bright-white tree growing near several temples. Sovann, their guide, tells him it’s a sralao tree. It’s almost too good to be true: a tree so distinctive that it will be easy to pick out in satellite photos. “There it is again,” Saturno says at a later temple, grinning.

Returning to the tower, where they’ve set up camp near a ramshackle concession stand, he couldn’t be more pleased. At around 11 the next morning, an Ikonos imaging satellite will pass over Lingapura, snapping images of the forest—including the sralao trees—below. Soon, Saturno and Evans will be back in their labs. And then the real archaeology will begin.

Satellite Power
Every few months, it seems, a discovery from the skies shakes up the world of archaeology. In Iraq, Harvard University archaeologist Jason Ur has revealed ancient irrigation canals that suggest that the 3,000-year-old Assyrian kingdom contained a network of previously undiscovered suburbs. At Easter Island, University of Hawaii and California State University scholars have exposed the paths—long a mystery—along which early Polynesians dragged statues. And in Guatemala, Saturno has uncovered sprawling Mayan sites dotted with hundreds of buildings.

This impulse skyward is not altogether new. Flying over Europe in World War I, conscripted archaeologists noticed enormous patterns in the crops below. Later excavations would show that these were remnants of buried settlements. Archaeology was transformed by the work of people like British Lieutenant-Colonel G.A. Beazeley, who once dryly noted that he was shot down before he could survey an irrigation system in Mesopotamia. Charles Lindbergh, an amateur enthusiast, discovered Pueblo cliff houses in the American Southwest and Mayan ruins in Central America. But only in the past few decades, with the introduction of remote sensing—digital sensors that illuminate the Earth’s surface from air or space—have archaeologists been able to expose sites invisible to the naked eye.

As the new methods spur increasingly spectacular discoveries, they are changing historians’ understanding of the ancient world. “People are looking at this data,” says Sarah Parcak, an archaeologist at the University of Alabama at Birmingham, “and going, ‘Oh my goodness, we’re going to have to reconceptualize our vision of ancient landscapes.’ ”

For archaeologists, the rise of remote sensing places a sudden premium on technical knowledge. In doing so, it rewards a certain comfort with computing not typically found among the old guard. Parcak was 23 when she started her dissertation on satellite imaging at the University of Cambridge. She searched papers in geology and other fields for information on how to analyze satellite images; there was no textbook for remote archaeology. (Now an old hand six years later, she’s writing it.) But the utility of her approach soon became clear.