To read this fascinating article in its complete form’ please go to: http://mashable.com/2013/11/06/space-archaeology/
Narrowing her eyes, keen with years of research and experience, Sarah Parcak squints past the dust and sand. Hands out, Egypt’s vast landscape at her fingertips, she’s searching for clues that will lead her to something extraordinary, buried and missing for thousands of years.
She and her team have been exploring the land for more than a year, looking for a settlement or structure that uncovers the ancient capital of Tanis. No one knows what it looks like, but Parcak has an idea. And she’s getting close.
Then suddenly, at the northeast region of the Nile Delta, administrative buildings, streets, palaces and houses of all sizes surface before her eyes. Parcak is excited. She has found Tanis. But she isn’t actually in Egypt — she’s thousands of miles away in her lab in Alabama, staring at processed, false color satellite imagery. It’s an emerging trend in archaeology that enables people to make extremely important archaeological finds — before excavating the area.
A fellow at National Geographic and an associate professor of anthropology at the University of Alabama at Birmingham, Parcak often tells her students, “A picture is worth a thousand words. A satellite image is worth a million dollars.” She’s a space archaeologist, part of a growing community of specialists who use satellite imagery and remote sensing technology to find ancient sites once invisible to the naked eye.
Often described by media outlets as a modern-day Indiana Jones — “Eat your heart out,” she tells Indy — Parcak insists that because this advanced technology can detect multiple sites at once, and even create 3D maps to aid researchers on the ground, the most exciting time to be an archaeologist is right now. “We have so many thousands of sites to find across the globe, and new techniques to test,” she tells Mashable. “The field keeps evolving with the technology, which makes things exciting.”And it’s true — space archaeologists like Parcak are quickly reinventing the way we study our past.
To find archaeological traces of Tanis, Egypt’s capital between ca. 1000 – 1400 B.C., she tried combining satellite datasets and running assorted processing techniques to enhance the imagery around the East Nile Delta. Using near-infrared satellite imagery, which reflects parts of the electromagnetic spectrum the human eye can’t see, she tracks subtle changes the Earth’s surface density, with different colors corresponding to different densities. Since Egyptians typically built their cities out of mud brick, denser than the soil around it, the satellite imagery revealed what appeared to be diagram of the ancient city.
“When the map first appeared, I didn’t know what I was looking at, since I had decided to test different techniques on a smaller subset of the imagery, for a faster processing time,” Parcak says. “It was only when I applied the same techniques to the entire image that I was able to see the map of the city for the first time.”
When she partnered with a French team to excavate and confirm one of the houses she found via satellite, Parcak realized the map was extremely accurate. “Now, for the first time in 3,000 years, we have a map of one of Egypt’s most important capitals “Now, for the first time in 3,000 years, we have a map of one of Egypt’s most important capitals,” she says.
From the phantom outline of a buried city thousands of miles away, Parcak could glean information not only about the layout and structure of Tanis, but also about its ruling class and urban development.
And this only scratched the surface of the technology’s potential..
“If you look on Google Earth, you have access to a satellite data product; you don’t have access to the data,” says William Saturno, assistant professor of archaeology at Boston University and former researcher with NASA’s Marshall Space Flight Center. “You have access to pictures that have been prepared for you.”
In contrast, space archaeologists use different wavelengths of light on images from NASA and commercial high-resolution satellite data to make the unseen become visible, teasing out deeper and subtler information about geology and vegetation on the Earth’s surface. That deeper information, according to Saturno, is where the importance lies. “What it [really] does is bombard the landscape with so many laser pulses — about a million every four or five seconds, in our case — [that will] hit the ground and return to the sensor attached to the [satellite],” he says.
The sensor measures the distance between the satellite and the ground by recording how long it took for the pulse to bounce back from the ground. GPS data allows the sensor to calculate exact coordinates on the ground in 3D.
Researchers end up with billions of points, Evans says, and specialized software can parse them, turning them into elevation models and more.
Remote sensing is especially useful for areas too dangerous for physical exploration or traditional digs. For example, Evans and Saturno used space archaeology to survey Lingapura, the ancient capital of the Angkorian empire in northwestern Cambodia, which Pol Pot and the Khmer Rouge littered with landmines in the 1970s. Evans and Saturno were able to map the area’s complex geography.
Amid fascinating discoveries, archaeologists also use satellites to track and stop professional looters, who expertly find — and often destroy — unprotected sites and steal important artifacts to sell to collectors and dealers. Within the archaeological community, researchers believe looting is the world’s third largest contributor to insurgency and criminal activity, but there are no globally accepted methods to track or curb it.
As with any discipline involving technology, space archaeology is advancing quickly. Within 35 years, satellite resolution has increased from 180 feet to 1.5 feet, and in 2014, DigitalGlobe will release the WorldView-3 satellite, with a resolution of about 1 foot.