From: UFO UpDates - Toronto <firstname.lastname@example.org> Date: Sat, 29 Mar 2003 07:08:22 -0500 Fwd Date: Sat, 29 Mar 2003 07:08:22 -0500 Subject: Scientists Finally Admit Mars Has Water + Life Source: Space.Com http://www.space.com/scienceastronomy/mars_streaks_030328.html Mars Water, Odd Surface Features Tied to Life By Leonard David Senior Space Writer posted: 07:30 am ET 28 March 2003 Mars is one wet and wild world. Scientists are slowly warming up to the view that trickling amounts of water on the cold, dry planet may be nourishing Martian biology. Thanks to spacecraft observations by the Mars Global Surveyor (MGS), newly formed dark slope streaks on Mars have been spotted. Emanating from a point source, they widen as they flow down slope. In some cases, they divide into separate streaks as they encounter other surface features. These sharp-edged dark stains always appear on slopes, mostly inside craters and valleys, but also on small hills. They are almost always located below Martian sea level - zero elevation. Over the last few years, cause for the streaks has been chalked up to the work of winds, or cascading surface materials. These processes would remove light-colored surface dust to expose darker bedrock beneath - so the thinking went. Let it flow A new view is that liquid flow is the most promising process for explaining the dark streaks. They appear to indicate currently flowing water on Mars. That's the interpretation of Tahirih Motazedian, carrying out independent undergraduate research at the Department of Geological Sciences and the University of Oregon. Images snapped by MGS months apart of a same area on Mars show that new streaks have formed within a time interval of months. "It could have happened in an hour or taken all of six months," Motazedian said during a presentation of her research findings at the 34th Lunar and Planetary Science Conference (LPSC), held March 17-21 in Houston, Texas. Heat source Motazedian said that the dark streaks can be found in various parts of Mars, but are heavily concentrated in the vicinity of Olympus Mons - a huge volcano on the red planet. Some form of geothermal activity on Mars -- acting either to melt subsurface ice or releasing water from liquid aquifers, or a combination of the two -- is releasing liquid onto the surface and forms the dark streaks, she said. It is possible, Motazedian suggested, that geothermal activity, driven by volcanic heat, is melting subsurface ice. This melting, in turn, releases a brine that dissolves surrounding minerals. Furthermore, the brine has a low freezing temperature, allowing it to flow at the Martian surface. The dissolved minerals precipitate from solution, leaving behind dark streaks of rock varnish. The most exciting thing about dark streaks is that they are currently forming today, Motazedian told the scientific gathering. "As I speak to your right now, there are dark streaks forming on Mars. That's literally true," she said. Not a dead planet The sharply-defined end-points of the dark streaks, Motazedian said, implies that the flows end where their liquid source is exhausted, having been consumed in a coating of surface dust and soaking into the ground. The dark streaks passively overlay other surface features on Mars without disturbing them or causing erosion. The dark streaks themselves have neither positive nor negative relief, Motazedian's research indicates. They appear as if they are stains on the existing topography, she reported. The amount of water flowing over the surface to create the streaks appears to be very, very small, Motazedian said. "It's pretty much soaking or sublimating (vaporizing) as soon as it comes down. So it's not forceful enough to erode a path for itself," she noted. "Mars is not a dead planet," Motazedian. "So I'm suggesting that all of you should quit your jobs and investigate dark streaks," she told the LPSC gathering. Streaks of microbial life Could the dark stains be biological? David McKay, a NASA space scientist at the Johnson Space Center in Houston, aired that prospect at the LPSC meeting. He is lead analyst in the ALH 84001 Mars meteorite detective work that suggests the rock sports the telltale signs of past life on the red planet. McKay offered an alternative view of the dark nature of the streaks. He speculated that there could be some dormant microbial life form that is rejuvenated by the water and, therefore, it is dark when it grows and then slowly dies off over months or years. "I'm suggesting this seriously as an explanation. I would like to see somebody demolish it_but it seems to me that with our current data we cannot exclude it," McKay said. Dark dune spots Also at LPSC, a team of Hungarian Mars researchers, led by Tibor Ganti and Andras Horvath, presented new work based on comparative MGS imagery taken over an extended time period. They see a tie between water in Mars' upper layer and the formation of what they call dark dune spots, or DDSs. They have charted the comings and goings, and rebirth of the DDSs from 1998 to 2002. In their view, the spots point to "some kind of biological activity of putative Mars surface organisms, acting on, or in, the material of the dark dunes." "The massive reappearance of the spots at their original sites seems to be compatible with our Mars surface organism hypothesis about the biological origin of dark dune spots," the researchers said. Evidence for water on the red planet documented by the Mars Odyssey spacecraft has bolstered the beliefs of the Hungarian Mars team. The prevalence of water seen by Odyssey ranges from the Mars' South Pole up to 60 degrees South. That coincides with the regions of the dark dune spots. "From this data we may deduce that water in some form is relatively abundant in the region of the dark dune spots," Ganti and Horvath reported at the LPSC meeting. Mars on ice There is no doubt that Mars is on ice, with huge reservoirs of frozen water hidden just below the planet's surface. The story of how much ice is sequestered subsurface continues to grow, said William Boynton of the University of Arizona and principal investigator for the Mars Odyssey's Gamma Ray Spectrometer. Data gleaned by Odyssey has shown tremendous water ice deposits, Boynton said. "It really is changing the way we think of how the ice formed," Boynton told SPACE.com . The idea that water vapor eked down to depths deep enough and cold enough to condense out does not seem to account for the vast amounts of water ice detected, he said. There's no telling how deep the ice might extend just below surface on Mars, Boynton said. It could be several hundreds of feet to well over a mile in depth. "All of a sudden you're starting to talk about a pretty significant amount of water," Boynton said. "It looks like the Viking 2 landing site was actually right on top of this ice. If its robot arm had dug just a little bit deeper they would have found it," he said. As for life being preserved in the ice or still kicking today, Boynton said that, with reasonable confidence he believes there's loads of ice on Mars. "If there is something that is happy living in ice_it is going to be very happy there," he said.
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