Archaeologists have developed a method of tracking human settlements using spy-satellite photos. This unique tool is revolutionizing traditional site excavation whereby archeologists are no longer on the hunt for ancient civilizations on foot. In using photos from the 60s, digital maps and contemporary multi-spectral images of the planets surface archaeologists are unraveling history digitally. The approach has already helped map some 14,000 settlement sites spanning over eight millennia in 23,000 square kilometers of Northeast Syria. Jason Ur, an archaeologist at Harvard University, and co-author of the study, told Nature :
Traditional archaeology goes straight to the biggest features—the palaces or cities—but we tend to ignore the settlements at the order end of the social spectrum.
The satellite-based method relies on the fact that human activity leaves a distinctive signature on the soil, called anthrosols. Formed from organic waste and decayed mud-brick architecture, anthrosols are imbued with higher levels of organic matter and have a finer texture and lighter appearance than undisturbed soil—resulting in reflective properties that can be seen by satellites.
Anthrosols being finer, lighter-colored and richer in organic matter comparatively to surrounding soil help making themselves visible in satellite images. This new development is a promising one for unlocking history and giving research access to the field digitally.