Martian ice could be sculpting surface patterns.Images taken by the Mars Global Surveyor The Mars Global Surveyor (MGS) was a US spacecraft developed by NASA and the Jet Propulsion Laboratory and launched November 1996. It began the United States's return to Mars after a 20-year absence. , now orbiting the Red Planet, suggest that most areas with geological features known as patterned ground Patterned ground is a term used to describe the distinct, and often symmetrical geometric shapes formed by ground material in periglacial regions. Typically found in remote regions of the Arctic, Antarctica, and the Australian outback, but also found anywhere that freezing and appear at high latitudes (Geog.) one designated by the higher figures; consequently, a latitude remote from the equator. - F. Harrison. that part of the earth's surface near either pole, esp. that part within either the arctic or the antarctic circle. See also: High Latitude , the same regions where large quantities of ice may lie just under the planet's surface. At hundreds of Martian sites, the landscape is covered with mosaics of polygons, each of which measures between 30 and 200 meters across. Some areas of patterned ground are heavily cratered or eroded, which probably indicates their great age. Most large areas of more-intact patterned ground are located at latitudes above 55[degrees], says William C. Feldman of the Los Alamos Los Alamos (lôs ăl`əmōs', lŏs), uninc. town (1990 pop. 11,455), seat of Los Alamos co., N central N.Mex. It is on a long mesa extending from the Jemez Mts. The U.S. (N.M.) National Laboratory. That pattern hints that climate played a role in the features' formation, Feldman and his colleagues contend in the Aug. 25 Journal of Geophysical Research Journal of Geophysical Research is a publication of the American Geophysical Union. JGR was formerly titled Terrestrial Magnetism from its founding by the AGU's president Louis A. (Planets). On Earth, patterned ground is formed by cycles of freezing and thawing in water-soaked soil or by the repeated expansion and contraction of subterranean ice (SN: 5/17/03, p. 314). The patterned ground on Mars appears in regions where orbiting instruments have previously detected high concentrations of hydrogen, which scientists propose is locked in water ice in the topmost layer of soil (SN: 6/8/02, p. 355). |
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