How Cutting-Edge Tech Is Empowering Ancient Archaeology
Lidar, drones, and more are helping field researchers uncover hidden worlds
Neal Spencer likes to travel light. Spencer is an archeologist and keeper of the Egypt and Sudan department at the British Museum, and he makes regular trips to Sudan in northeast Africa. His current dig is at the site of an ancient walled town occupied by Egypt’s pharaohs from around 1500 to 1070 B.C. For these expeditions, he usually packs trowels and brushes, notebooks, cameras, water filters, laptops, and mosquito nets. Oh, and a lightweight camera drone.
“These days, it’s hard to imagine life without it,” he told me when we spoke recently. “And things are so much better when you can fit everything in your hand baggage.”
The legendary archaeological excavations of the late 19th and early 20th centuries operated on an almost immeasurably bigger scale. When German archeologist Heinrich Schliemann excavated the ancient city of Troy, now in northern Turkey, in the 1870s, he employed teams of up to 160 laborers working over three years. These digs were destructive, too. Schliemann himself resorted to using dynamite, and scholars later accused him of causing even more damage than the 12th century B.C. Greek invasion.
Where once archeologists excavating ancient ruins had little more than oral texts, haphazard plans, and aerial photographs to guide them, an archeological revolution has been under way over the last 15 years — and technology is almost entirely responsible. When a sprawling Mayan megalopolis was uncovered in northern Guatemala in February 2018, archeologists used a low-flying aircraft equipped with a lidar camera (light detection and ranging) that allowed researchers to see through dense jungle canopy. They located some 61,000 ancient structures hidden deep beneath the soil, then plotted them onto a virtual 3D environment. No digging necessary — and definitely no dynamite.
“The tech we’re using has really transformed our way of looking,” Spencer said.
On the ground, “remote sensing” technologies such as ground-penetrating radar and magnetometry can peer deep beneath the earth, building up images of ancient subterranean structures.
Drones have been the true game changer. Instead of mounting large-scale survey expeditions and manually plotting sites inch by inch, Spencer and his colleagues can now send up a flying camera and create a three-dimensional digital model on their laptops. These reveal where walls once lay, where wells were dug, where field boundaries were laid down — detailed, granular information that helps target further analysis, all in a matter of hours.
On the ground, “remote sensing” technologies such as ground-penetrating radar and magnetometry can peer deep beneath the earth, building up images of ancient subterranean structures. Even a consumer SLR camera can be adapted: By swapping its sensor for one with infrared sensitivity, it can detect the telltale, copper-based pigment known as Egyptian blue, which is invisible to the naked eye. Long-hidden inscriptions can be revealed.
“That modification cost about £60 [$75],” Spencer explained. “The drone might be £200 [$250]. Archeology is a shoestring operation.”
Borrowing from innovations created for wealthier industries such as oil exploration and medicine, Spencer and his colleagues have passed ancient mummies through CT scanners, searching for objects buried within wrappings or even hieroglyphic carvings just a few millimeters deep.
By taking ground samples and examining them under polarized light, a technique known as micromorphology, it is possible to see how water splashed and pooled on a floor thousands of years ago alongside other deposits. Archaeologists can see evidence that a room was a kitchen or that another one was used to house herbivorous animals.
“It looks like a mud floor, but when you analyze it, you see dozens of events,” Spencer said. “We see how space was actually used. It’s very bottom-up; you can draw implications from really tiny things.”
Spencer is particularly excited about another technique called strontium isotope analysis. Much like carbon dating of organic materials, examining the buildup of strontium in human or animal remains — particularly in teeth — enables archeologists to plot migration patterns. If bodies in a graveyard have a strontium signature markedly different from ambient readings (or those of nearby remains), it likely indicates they originated from elsewhere. A picture of how migration or trade operated in the society in question begins to form.
Even better, many of these techniques are noninvasive, enabling archeologists to scroll back hundreds or thousands of years without disturbing anything in the present. “These days, when we do dig, we know what we’re digging for,” Spencer said. “We’re not digging to find things; we’re digging to find out about things.”
Precision scanning of classic structures has a role for more recent historical work. In 2015, a pioneering architectural historian at Vassar College named Andrew Tallon made laser scans of Notre Dame’s interior, accurate to within a millimeter. After the devastating fire that gutted the cathedral in April, those images could now be used to help rebuild it.
Among other firms, the Oakland-based nonprofit CyArk specializes in scanning large cultural and historical sites, working on projects as diverse as Angkor Wat, Pompeii, and the Stonewall National Monument in New York City. Using state-of-the-art laser scanners, surveyors create complex 3D “point clouds” — a hyper-accurate digital survey that can pick up every fissure in a wall or subtle indentation on a ceiling.
The major issue used to be lack of information — is that shallow barrow a religious site or something else entirely? Now the discipline is drowning in information.
The data can show how a structure is degrading over time or how it was constructed. For medieval or earlier buildings, it’s rare for construction plans to survive (which makes Tallon’s scans of Notre Dame especially valuable). By chance, CyArk happened to scan three of the Buddhist temples at Bagan in Myanmar shortly before they were hit by a 6.8-Richter-scale earthquake in August 2016. The data they collected is being used to help restore the 11th and 13th century temples.
If you’re trying to create a rough-and-ready survey, you don’t even need a specialist firm: These days, many archeologists simply download a 3D-scanning app to their smartphones and do it themselves. “It really does change the way we go about what we do,” said Spencer. “Low-cost imaging is the most incredible research tool.”
So what does the future hold for those obsessively trying to document the past? Likely next steps are more sophisticated uses of the rich data that’s now being collected. CyArk has made many of its surveys freely available online, hoping to build a digital library of historic structures across the world. Spencer is fascinated by the potential of “virtual autopsies,” a medical technique that combines CT and MRI scanning to provide a forensic, noninvasive analysis of how someone died — even if that someone happened to die several thousand years ago.
Ironically, Spencer pointed out, the danger for archeologists may now be too much data. The major issue used to be lack of information — is that shallow barrow a religious site, a living space, an empty burial pit, or something else entirely? Now the discipline is drowning in information: When every square millimeter of soil can reveal its secrets, it can be hard to know where to stop. Or even where to start. “If you’re not careful, you can get completely flooded,” Spencer said.
“It’s about finding ways to manage that,” he added, with a trace of a sigh. “Not seeing the wood for the trees, that’s the next big problem.”