Satellites Unearthing Ancient Egyptian Ruins

Old and modern methods

Parcak's process weds modern tools with old-fashioned grunt work.

The archaeologist studies satellite images stored on a NASA database and plugs in global positioning coordinates for suspected sites, then tramps out to see them. Telltale signs such as raised elevations and pot shards can confirm the images.

As a result, the big picture comes into view.

"We can see patterns in settlements that correspond to the [historical] texts," Parcak said, "such as if foreign invasions affected the occupation of ancient sites.

"We can see where the Romans built over what the Egyptians had built, and where the Coptic Christians built over what the Romans had built.

"It's an incredible continuity of occupation and reuse."

The flooding and meanders of the Nile over the millennia dictated where and how ancient Egyptians lived, and the profusion of new data has built a more precise picture of how that worked.

"Surveys give us information about broader ancient settlement patterns, such as patterns of city growth and collapse over time, that excavations do not," said Parcak, author of a forthcoming book titled "Satellite Remote Sensing and Archaeology."

The vagaries of climate in the region make satellite technology advantageous, too.

"Certain plants that may indicate sites grow during certain times of the year," Parcak said, "while sites may only appear during a wet or dry season. This is different everywhere in the world."

Archaeologists working in much more verdant climates, such as Cambodia and Guatemala, also have used the technology to divine locations of undiscovered ruins.

They have been able to see similarities between the vegetation at known sites and suspected sites that showed up in fine infrared and ultraviolet images covering wide areas of forbidding terrain.

"For the work I do [in Egypt], I need wet season images as wet soil does a better job at detecting sites with the satellite imagery data I use," Parcak said. "I can pick the exact months I need with the NASA satellite datasets."