In this article, BBC News writes that two researchers in Israel have shown that "satellites could be used to spot ancient archaeological treasures buried underground."
Dan Blumberg and Julian Daniels, of the Ben Gurion University, told New Scientist magazine how they were able to detect flat squares of aluminium which they had buried at different depths in the sand of the Negev desert.
The pair used radar sensors on board an aircraft. "Now we have systematic proof. Buried objects can be detected from airborne systems," Dr Blumberg said.
They think they can add new sensors to satellites. Here is a picture of one European Remote Sensing (ERS) satellite from the European Space Agency (ESA), which might one day have archaeological missions.
This preview of the article of New Scientist -- to appear on July 12 -- contains more technical details.
So far, the researchers have only looked for objects buried up to 40 centimetres deep. But now that they have proved the technique works, they are planning studies with different types of object, buried deeper.
For their experiments, they use microwaves of the longest possible wavelength, called P-band. At the moment, satellites generally use microwaves with shorter wavelengths because the resolution is better. But P-band radiation can penetrate farther underground, so Blumberg hopes that adding it to satellite sensors will allow them to probe deeper, perhaps up to 9 metres down.
What are the possible applications of this new satellite imagery?
Blumberg hopes that as well as archaeological remains, the method will in time be used to find fossils and geological structures. There could also be military or humanitarian applications. The resolution would probably be too low to pick up individual landmines, but it could show underground buildings or pipes, or perhaps even mass graves.
But are there limitations? Yes, and pretty severe.
The main snag is that radar can only penetrate the ground in very dry areas, because liquid water tends to absorb the radiation. But Blumberg says that 15 per cent of the Earth's surface is dry enough for the method to work, including the Antarctic and deserts. The surfaces of some planets and moons fit the bill too, he points out. He hopes P-band radar might be used to reveal structures such as water channels below the dry, frozen surface of Mars.
Sources: BBC News, July 9, 2003; New Scientist, through EurekAlert!, July 9, 2003
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