Word: crusting
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Back in the days when Grandpa went to grade school, geography teachers had no trouble explaining how the earth's mountains are formed. The earth is cooling and shrinking, they told the kids; its crust has wrinkled into mountain ranges like the skin of a drying apple. Modern geophysicists, who believe that the earth was cold when it started its career, have abandoned this charmingly simple theory. Trouble is, they have had little luck developing a satisfactory substitute...
Most of the earth's material is plastic enough to contract evenly, but the thin surface crust is rigid. Instead of contracting smoothly when the core shrank, it cracked and wrinkled, just as in the old theory. Sometimes parts of the earth's crust slid over other parts like sheets of ice in a fast-flowing river. These surface irregularities, much changed by erosion, are the earth's mountains...
...responsible for dozens of the burgeoning brood of refineries and petrochemical plants that have sprung up in the South and Southwest, also handled the reconstruction of Guam after World War II. Recently, Brown & Root snagged the prestigious $40 million Mohole contract to drill through the earth's crust, and it has just started construction of NASA's $90 million Manned Spacecraft Center near Houston. Its average yearly business: $300 million...
Photographs taken through the great telescope at California's Lick Observatory, and released last week, reveal the moon's pockmarked crust in astonishing detail (see cut). Forbidding mountains loom above broad valleys and sharply defined crevasses, just as they will appear to approaching astronauts. But for all their clarity, the pictures leave a vital question unanswered. What is the moon actually made...
...moon, says Astronomer Cudaback, is probably covered by a thick porous layer that is as light and airy as finespun cotton candy. It is also possible, he says, that there is a foamy crust of crumbly, crackerjack-like material or a lunar honeycomb with cells intact and filled with gas. The moon got that way, he figures, because it has been bombarded with meteors for billions of years. Striking the moon's skin with enough energy to melt 100 times their own mass, the meteors liquefied rock or whatever else they hit, splashing gobs of molten material all over...