Word: crater
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
...Mars is as old as the surface of the moon, say Physicists Edward Anders of the University of Chicago and James R. Arnold of the University of California, San Diego. If that were so, the two men argue in the latest issue of Science, Mars would show many more craters than it appears to have. Assuming a fairly constant supply of crater-forming asteroids, Mars, which is far closer to the asteroid belt, would have been hit up to 25 times more often than the moon. There would be as many as 220 craters...
...same issue of Science, other researchers offer much the same conclusion. All of which suggests that other Martian craters, predating those that Mariner saw, formed and vanished eons ago. What happened to them? All the researchers agree that they must have been eroded away - perhaps by swirling dust storms, perhaps by a flow of Martian water. "In any event," conclude Anders and Arnold, "the crater density on Mars no longer precludes the possibility that liquid water and a denser atmosphere were present on Mars during the first 3.5 billion years of its history." If there was water, there may have...
...steel beer keg and is big enough to swallow an entire Apollo moonship, will go into operation later this year. At the edge of the space center, a field covered with heaps of steel-mill slag and pumice is used as a practice area for simulated exploration of a crater-pocked lunar landscape...
Writing in Nature, Physicist Clyde Cowan of Catholic University of America, along with Geophysicist Chandra Atluri and Nobel Prizewinning Chemist Willard Libby of U.C.L.A., offer the most ingenious theory so far. After disposing of previous guesses (If it was a meteor, where is the crater? If it was a comet, why was it not seen approaching?), Libby & Co. suggest that what caused the big bang may well have been a hunk of antimatter that must have wandered into the solar system from some distant galaxy...
Faster and faster fell Ranger IX, tugged by the moon's gravitation until it reached the speed of nearly 6,000 m.p.h. Its cameras never faltered. They sent their pictures to the end, giving countless millions of televiewers a look at the crater floor as it might be seen from the cockpit of a spacecraft about to land. The last pictures were transmitted just .45 seconds before impact from three-quarters of a mile above the lunar surface. They showed objects as small as ten inches...