Word: kuiper
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Dates: during 1960-1969
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Stupendous Collision. To University of Arizona Astronomer Gerard Kuiper, one of the world's leading lunar experts, Orbiter's photograph seemed to confirm his theory that the 1,000-ft.-high mountains in the center of Copernicus were partially formed by volcanic activity. Scattered over their slopes, he says, are humps similar to the cinder cones found on major terrestrial volcanoes. The picture also clearly shows that the floor of the crater is remarkably flat. To Kuiper, this indicates that the subsurface was once in a fluid or plastic state, and that it solidified, causing the crater floor...
These clues strengthen Kuiper's belief that Copernicus was formed by the impact of a comet, one of three or four that have hit the visible side of the moon during its 4½-billion-year lifetime. He estimates that the comet weighed a million million tons, had a nucleus ten miles in diameter, and crashed into the moon at a speed of 35 miles per second. The explosion produced by the stupendous collision was intensified by the comet's high content of ice expanding into steam on impact. The resulting blast produced a crater 60 miles across...
...heat of impact and the resulting steam penetrated deep into the moon and formed a pool of molten material that later solidified as the crater floor. The hot lunar material and huge chunks of rubble floating in it, says Kuiper, created the volcanic structures that can be seen in Orbiter's picture...
Though Luna 9 successfully disposed of the hypothetical thick layers of lunar dust, said University of Arizona Astronomer Gerard Kuiper, some parts of the moon could still present a hazard to landing spacecraft. Photographs from the U.S. Ranger 9 moon probe show that between 5% and 10% of the lunar surface is covered by depressions, apparently areas of thin crust that have sagged into caves or voids under the surface. Should a spacecraft land on such a crust, he believes, it might crash through into the cave below...
...during the past several years has stood nearly alone in insisting that there is little or no lunar dust: "There was never any basis for believing it anyway, but the idea seemed to fascinate people in the same way as flying saucers." The surface of the Ocean of Storms, Kuiper said, seemed to have been formed by lava flow during volcanic activity billions of years ago. "It must be nasty stuff to walk on," he said, "brittle, sharp and full of little holes." The first lunar explorers, he feels sure, will have to be equipped with some form of snowshoe...