Scientists Have an Audacious Plan to Map the Ancient World Before It Disappears

My final evening in Croatia, the project leaders gathered at a local townhouse for an update. Conyers had spent several hours that day going back through his data. He looked mischievous but focused, with the cheerfulness of a man who believes he’s won a bet. “We got it all wrong,” he said. He was grinning.

What followed was a masterclass in interpretation and its dangers. Conyers drew our attention to what we had thought were architectural features. Those, he clarified, were just bursts of interference from a nearby cell tower. “We saw this,” Conyers explained, pointing at his screen, “and we said, ‘Wall! Wall!’ I wanted to see walls. I wanted walls and floors to be banging back at me. But”—he clicked through a few more radar profiles—“I see no walls. We’re doing geology here, not archaeology.” He described an area at the top of the hill that he had been particularly excited about, thinking it might be the floor of an ancient room, but it was just a natural depression framed by boulders, buried under soil and plants. The group would go on to discover pottery sherds and evidence of inhabitation, spanning thousands of years, but grandiose architecture was in short supply. It might not be a building, but for Conyers it was still a puzzle, something to solve.

In her book The Ruins Lesson, Susan Stewart, a poet and historian at Princeton, writes: “It is not ruin, but preservation, that is the exception.” Empires fall, cities are abandoned, buildings crumble. But the tools of geophysics change Stewart’s equation. Seen through devices such as ground-penetrating radar or magnetometry, it is preservation, not ruin, that is the rule. Even the most temporary village or house—even the briefest of human lives—leaves a signature behind in the soil. The unexpected lesson of these new instruments is that none of us ever fully disappear. Our homes and apartments, even our campfires, leave traces in the ground that someone, someday, will be able to find. Thanks to geophysics, the Earth is an archive of electromagnetic shapes, a hidden collection of the human past.

And that past is about to get more democratic. Instead of relying on picturesque ruins—the accumulated riches of aristocrats, military leaders, and religious authorities—geophysics helps us explore even the most ephemeral lives of everyday people, in high resolution. Eras that historians might have previously overlooked, even entire cultures and peoples, may finally get the attention they deserve. Just as lidar technology allowed archaeologists to look through the dense rainforest canopies of South America and Southeast Asia and reveal ancient cities, the tools of geophysics are now doing the same for cultures in sub-Saharan Africa and Indigenous North America. The people in these regions tended to use organic and biodegradable building materials, creating the illusion, millennia later, that they were not sophisticated, did not build significant works of architecture, and had no true lasting legacy. A truly global International Subsurface Exploration Agency, of the kind Trinks proposes, would radically expand our understanding of who has left a mark on human history.

Before I left Vienna, Alois Hinterleitner had showed me what this new archaeology actually looks like, how lost cities reappear, from their abandoned streets to their ovens and farms, when seen through the lens of geophysics. Stationed in front of a large-screen TV hooked up to a laptop, with his sinewy mountain-climber’s forearms, Hinterleitner had clicked through a series of radar surveys recorded at Carnuntum. As he turned different filters on and off, what began as a random fuzz of black and white pixels became a clearly defined maze of walls and building foundations, dark architectural forms lurking in the data. Someday, this could be the entire Earth’s surface, I realized, a screen through which we can see the past. Then Hinterleitner reversed the process until everything we’d seen or thought we’d seen, from Roman ruins to modern plow marks, disappeared again into a sea of white noise.

Research for this article was supported by a grant from the Graham Foundation for Advanced Studies in the Fine Arts.

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