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2008-01-07

Satellites build a picture of the past

"When NASA's only archaeologist, Tom Sever, looked at an infrared satellite image of a Mayan city in Guatemala, he was intrigued to see the vegetation around the buildings showed up as much brighter than the vegetation in other areas. Following a hunch, Sever, based at the Marshall Space Flight Centre in Hunstville, Alabama, looked for other patches of bright vegetation on the U.S. space agency's maps.

Sure enough, he found additional bright spots at sites not previously considered for archaeological digs.

Sever hypothesised that the limestone that the Maya used for building had leeched into the soil, altering vegetation at these sites. Since chlorophyll in plants glows brightly in the infrared range, NASA's satellites were able to pick up the subtle difference in vegetation. With this new method in their toolkit, archaeologists went on to discover several previously unknown Mayan cities."

http://www.cosmosmagazine.com/node/1764

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