Martian highlands: clues to a watery past?For years, astronomers studying Mars have all but ignored the planet's southern highlands The Southern Highlands could refer to:
Their study of images made by the Viking spacecraft more than a decade ago reveals that Argyle Planitia, the second-largest impact basin in the highlands, contains layers of material that could be sediment from a huge body of water held by the basin millions of years ago. In addition, three networks of channels appear to lead into the basin from the south. Other channels slope northward out of the basin, which has a diameter of some 1,200 kilometers. Timothy J. Parker and Donn S. Gorsline of the University of Southern California The U.S. News & World Report ranked USC 27th among all universities in the United States in its 2008 ranking of "America's Best Colleges", also designating it as one of the "most selective universities" for admitting 8,634 of the almost 34,000 who applied for freshman admission in Los Angeles Los Angeles (lôs ăn`jələs, lŏs, ăn`jəlēz'), city (1990 pop. 3,485,398), seat of Los Angeles co., S Calif.; inc. 1850. conjecture that Mars' atmospheric pressure atmospheric pressure or barometric pressure Force per unit area exerted by the air above the surface of the Earth. Standard sea-level pressure, by definition, equals 1 atmosphere (atm), or 29.92 in. (760 mm) of mercury, 14.70 lbs per square in., or 101. was once high enough and the planet's southern polar ice cap
"The [channels] are the smoking gun -- or squirting squirt v. squirt·ed, squirt·ing, squirts v.intr. 1. To issue forth in a thin forceful stream or jet; spurt. 2. To eject liquid in a jet. v.tr. 1. gun -- to support the contention that there had been standing water in the basin," says Parker, who reported the work last week at a meeting of the American Geophysical Union The American Geophysical Union (or AGU) is a nonprofit organization of geophysicists, consisting of over 50,000 members from over 140 countries. AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and in Baltimore. He notes that the study supports the oft-debated idea that Mars once had lakes or planet-wide seas. But Parker adds that previous evidence for a watery Mars has come primarily from studies of the planet's northern hemisphere. Even if current speculation about Argyle Planitia does hold water, Parker says, it's unclear whether the basin contained a windy lake or a still, ice-covered reservoir. He notes that the basin may be a prime site to look for organic material -- the possible precursor of primitive life --on the Red Planet. The Mars Observer Mars Observer, launched by NASA in September 25, 1992, was the first of the proposed Observer series of planetary missions, and was designed to study the geoscience and climate of Mars. spacecraft, which will begin studying the planet in November, could shed further light on the history of the basin, Parker notes. A Russian craft, Mars 94, set for launch next year and scheduled to arrive at Mars in 1995, may also have a chance to photograph the basin. COPYRIGHT Science Service Inc. 1993 |
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