Dataon Mars Indicate It's a Dynamic Planet
By John Noble Wilford Special to The New York Times
Pictures and data transmitted to earth from Mars by US Mariner 9, surveying 85% of Martian surface, reveal high winds, temperature extremes, deep chasms, glacial terraces, moonâlike craters, water vapor and dust clouds, volcanoes and meandering channels, proving Mars is much more dynamic planet than thought after previous Mariner satellite surveys; project scientist R H Steinbacher repts at news conf on June 14 that most important discovery is evidence that water has played active role in evolution of Mars, based on contention that south polar ice cap may be partly frozen water, not all frozen carbon dioxide (dry ice), and detection of channels which may have been eroded by streams, rains and floods within last 50,000 yrs; theories explaining how such water could have been released include 1 contending that shifting position of planet's axis causes melting of polar regions when they are exposed to high doses of sunlight every 50,000 yrs; another holds volcanic heat could have melted permafrost stored beneath Martian surface and caused deep faults and sinuous riverbeds in crust; H Masursky of US Geological Survey says that determination of water presence is central to answering question of whether Mars has been suitable for life development; predicts that future Marsâlanding missions may find fossils or signs of life; Mariner 9's 428 revolutions of Mars have produced 7,000 TV pictures, which have been perfected by computer; photos identify 4 major geological provinces; volcanic province's most prominent peak is larger than that in Hawaii; equatorial plateau province, marked by cracks which indicate tectonic (earthquakeâlike) activity, has canyon 10 times length and 3 times depth of US Grand Canyon; crater terrains of 3d province cover 1/2 of planet and seem to be its most ancient feature; 4th province is expanse of stairâstep terraces and deep grooves which radiate from south polar area and are believed to have been gouged by moving ice cap; north polar region, though not yet completely photographed, is expected to be similar, indicating that Mars, like Earth, has had ice age and is now in warmer period; other Mariner 9 findings are that temperature ranges from 200 degrees below zero at North Pole to 80 degrees above zero in equatorial zone, that atmospheric winds reach 115 mph normally and 300 mph during dust storms, that amt of ozone, which is necessary to life because it screens out lethal ultraviolet sun rays, is less than 1/100 of amount in earth atmosphere, that Mars is somewhat circular but suffers from variations in gravitational pull, and that south polar cap recedes about 1,800âmi in diameter between winter and spring; Goddard Space Flight Center's Dr R A Hanel says that although prospect of life on Mars is not certain, evidence gathered by Mariner 9 supports prospect of life elsewhere in solar system; history of Mariner 9 project revd; map of Martian equatorial region; illus of part of Martian north polar region; diagram of solar system