Word: layering
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...rounds of American museums in the 1980s as examples of hammered gold. Then Heather Lechtman, an M.I.T. archaeologist interested in ancient technologies, examined the metal and discovered that it represented a far more sophisticated art. Lechtman's analysis revealed that the artifacts had been gilded with an incredibly thin layer of gold using a chemical technique that achieved the quality of modern electroplating. No one had previously suspected that these Indians had the know-how to create so subtle a technology...
This week the space shuttle Discovery is scheduled to deploy the first satellite in the Mission to Planet Earth, an ambitious, long-range program to monitor the planet's pulse. This particular satellite carries four instruments to gather information about the atmosphere's vital ozone layer. The most important goal is to measure how badly this fragile band, which protects the earth from the harmful ultraviolet rays in sunlight, is being depleted by the industrial chemicals known as CFCs...
...late 1970s and showed it had a far higher content of the rare element iridium than ordinarily found in the earth's crust. It was this discovery that led Luis Alvarez to his momentous - insight. Comets and asteroids have high iridium content, he reasoned, and the clay layer could have been formed by the worldwide fallout of the material vaporized when an errant asteroid or, as most scientists now suspect, a giant comet smacked into the earth...
This week, at an astronomy conference in Flagstaff, Ariz., scientists will add an intriguing twist to the Alvarez scenario. Their interpretation is based on new evidence that the Cretaceous-clay boundary actually consists of two parts: a thin layer overlying a more substantial one. To Eugene Shoemaker, of the U.S. Geological Survey and a co-author of the report, two layers indicate not one but two impacts...
...program is poorly understood and promises unbelievable benefits. It's essentially a large number of satellites and earth-observing stations that will accurately measure the earth's atmosphere. We'll be able to see where the ozone layer has been damaged, for example, and see if something can be done to fix it. It's an indication that NASA funds programs looking at both today's problems and tomorrow's possibilities...