Forensics 101: Space Archeology?

A new term came to my attention last week, one that on first glance seems a bit of a misnomer. It came tied to a really neat story, so we’re going to look at the scientific field this week—what these scientists do and what their work tells them—and then we’ll explore their groundbreaking discovery next week.

The term is ‘space archeology’ or, alternatively, ‘remote sensing techniques in archaeology’ (though I think we’d all agree ‘space archeology’ is WAY cooler). At first glance, one would think this is simply archeology in space, except we’re nowhere near having the skills or technology to do that. So what is space archeology? In the end, the answer is quite clever: it’s using satellite scans of the earth taken from space to identify previously undiscovered archeological sites.

The way space archeologists do their work is quite ingenious. Visible light scans of the planet’s surface may show absolutely nothing. But when infrared scans are used after being processed using false colour, chemical changes to the landscape caused by building materials and the activities of ancient civilizations are revealed. NASA’s high resolution scans are used as the raw data for the analysis, allowing scientists to discern subtle variations in the earth’s topography. The key to this analysis is grounded in vegetation—plants that live on top of stone are simply less healthy and will have reduced levels of chlorophyll. Find the unhealthy plants, and you may be well on your way to finding the site of an ancient civilization.

Enter Dr. Sarah Parcak, an archeologist at University of Alabama at Birmingham. She is responsible for the discovery of several amazing archeological sites, many of them lost for centuries or even millennia. For instance, the picture above shows an infrared scan of what looks to the naked eye like a patch of desert. But move out of the frequency of visible light and into infrared, and suddenly a network of city streets and buildings are revealed. It’s an amazing look at what hides below the earth’s surface. Which city is this? Tanis, the historical city used in Raiders of the Lost Ark, lost for over three millennia to the sands of time. So far only a small trial area has been excavated, but mud-brick structures were discovered a foot below the modern surface.

Next week we’ll be back to talk about an amazing discovery that could rewrite the early history of North America. See you then…

Photo credit: University of Alabama at Birmingham