How archaeologists are using today's tools to unearth the past
Archaeologists - armed for centuries with little but a pickax and patience - are turning to such space-age tools as particle physics and satellites to dig up the past. And their new tools and techniques are yielding a rucksackful of new knowledge.
The use of these tools is also hastening the epochmaking change of emphasis in archaeology away from the pictures pieced together from artifacts alone, toward a more complete view of earlier societies - their life styles, the food people ate, the water they drank, and the links between their civilizations and others.
''Profound is too mild a word to describe the impact science is having on archaeology today,'' says Al Wesolowsky, managing editor of Boston University's prestigious Journal of Field Archaeology. Windows on the past are being opened where, even 10 years ago, no one imagined they could be.
Consider, for example, a dig in progress in Egypt's Valley of the Kings, a dusty historical treasure-trove along the banks of the Nile which includes, among other things, the tomb of Tutankhamen. Here a group from the University of California at Berkeley has been toiling for the past five years to map the Theban Necropolis.
While shovels and trowels are still in evidence, so is a host of new equipment. On the ground, lasers and electronic surveying equipment have furnished, in a matter of minutes, the kind of distance measurements that used to require days of effort. Photographers take to the air in balloons and low-flying aircraft.
Besides helping to map the site quickly and precisely, the aerial shots have pinpointed several previously undiscovered burial chambers.
Using sonic devices, excavators pulse sound waves into the valley floor and surrounding cliffs to help locate hidden tombs. Field data are fed into a computer, which displays three-dimensional representations of temples, accurate to within a fraction of an inch.
The importance of the new techniques goes beyond just a quicker way to do what was done before. Many burial grounds around the world are being threatened by tourism, erosion, and even modern grave robbers. Scientists say the new tools are helping them record valuable details before more of the record is lost.
Israel offers another example of how science is turning up secrets about the past. Archaeologists have been searching since 1972 for the tomb of Herod the Great (73?-4 BC), the biblical monarch, at a remote site outside Bethlehem.
Earlier this year, local excavators were joined by a team from SRI International, a California research firm. The US group brought its own tools: ground-penetrating radar, seismic sounders that use high-frequency waves to ''see'' 100 feet into rock, and ''automatic resistivity'' devices, which help map a site by shooting electrical currents into the ground.
Within a matter of days, the scientists were able to locate five new chambers - one of which could turn out to be the long-sought tomb.
''An archaeologist might spend 10 to 20 years digging at a site,'' says Lampert Dolphin, one of the SRI physicists who made the trip. ''We can come in a few days and tell them a great deal about what lies below the surface, without destroying the surroundings.''
In the laboratory, new chemical methods are being tapped to date and analyze pieces of the past. One process being used more frequently, for instance, is infrared spectroscopy, in which infrared light is shot into an artifact. Those light waves, which are absorbed at different wavelengths, create a ''fingerprint'' which can then be compared with those found in other regions. Scientists can then piece together the trade and social patterns of early man.
Chemical contaminants in pieces of amber traded in ancient Europe have revealed much about the flow of commerce between Scandinavia and southern Europe from 3500 to 1000 BC.
And at the University of Minnesota in Duluth, scientists have gleaned new insights into the trade patterns of early Indians in the region by studying trace elements in copper.
Remote sensing - the interpretation of photographs and data from radar-equipped aircraft and earth-orbiting satellites - is also expanding the archaeological horizons.
''We are trying to cultivate a new breed of archaeologist who will know how to think about all these options,'' says Dr. Martha Joukowsky, an assistant archaeology professor at Brown University, who has written a book on archaeological methods.
As archaeology marches into the modern age, though, it is proceeding at a leisurely gait. Besides the limitations imposed by the high cost of the new tools, the field remains one in which human elements - perseverance, judgment, and instinct - still play a big part.