Relics uncovered: Mayan ruins in Guatemala.
Credit: Tom Sever
If they haven't been destroyed or dismantled, many ancient structures were long ago enveloped by soil, water, sand, volcanic ash, or thick vegetation. Though they might not be obvious to the naked eye, archaeologists are learning how to spot them.
Since the World War I, aerial photography from low-flying aircraft has been widely used. These images can help to pick out relics betrayed by unusual mounds, lines or disjointed landscapes. In other places, buried structures are completely invisible to the naked eye. But they still reveal clues to their whereabouts - just not with visible light.
The human eye can detect wavelengths of light within the range of around 400 to 700 nanometres. But cameras attached to satellites and aircraft are now taking infrared and ultraviolet shots over a much wider range of wavelengths – and revealing some remarkable details about ancient civilisations.
Mayan cities
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 leached 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.
Spotting entire new cities is one thing, but these images can also provide intricate data about already well-known sites.
Payson Sheets, a professor of archaeology at the University of Colorado, has directed the Arenal Research Project in northwestern Costa Rica since the 1980s. He has used similar infrared images from NASA satellites and aircraft to solve a long-standing mystery.
RE: Closing
There's actually another freeware Earth Imagery Satellite software and it's made by NASA. It's called WorldWind... look it up! :)
Look, never mind the loose
Look, never mind the loose paraphrasing. My point still stands that the author is clumping folks into a category with Gates, just because they picked up Google Earth. It's a ridiculous association. Maybe ten years ago, when this tech wasn't very accessible, you could get away with making that association. But it's 2008, and making weak references to Gates like this is an indication that the speaker is out of the loop.
Actually, Indiana Jones was
Actually, Indiana Jones was (rather loosely) based on an historical figure named Giovanni Belzoni. One could he wasn't a true archeologist, certainly, but he was (part of) where the science came from.
Just who the heck is Bill
Just who the heck is Bill Gates?
This is Bill Gates!
http://gizmodo.com/341472/this-video-makes-bill-gates-look-cooler-than-steve-jobs
Bill Gates????
Come on! Bill Gates? If Bill Gates owned Google you would be charged big time for this ability and would probably have to use some proprietary Microsoft software to do it. Since Google is based on and built with Linux a more appropriate, and also more ethical choice, would be Linus Torvalds, not Bill (I gotta own everything) Gates! If Gates was involved you would never see these discoveries.
Linus?
Since this discussion is nothing but snark, why invoke Tovalds in a Google discussion? Wouldn't the Google founders (Page and Brin) be better choices since they actually did what you discussed, in fact, they BOUGHT the software that GE is based on and then gave it away (at least a pretty good version is free).
Actually, the original
Actually, the original Keyhole "Earth Viewer" had a pretty good free version already, pre-Google, and an active community (hence Google Earth Communitys url).
This was covered a while
This was covered a while back on PBS. You can watch a short program about it online.
"NASA archeologists use satellites to pinpoint ancient ruins buried
deep in the jungle."
Link: http://www.pbs.org/wgbh/nova/sciencenow/3401/03.html
This whole story, then not
This whole story, then not linking?! Add the links to the end of the story, is that so hard?
Where is the IR imagery from?
I'm missing how he managed to view IR imagery from Google Earth. Sure NASA has sensors and maps of it, but out of the box Google Earth serves up only visible imagery.