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Two scientists recently said that enough water can exist on the surface of planet Mars to sustain life.
Lawrence Kuznetz, a researcher at the University of California at Berkeley's department of planetary sciences, said his experiments show that liquid water can exist under Martian environmental conditions and the low atmospheric pressure found on the planet.
From tests done in the 1960s of cooling systems for astronaut spacesuits, Kuznetz said he found that water exists in liquid form under the low atmospheric pressure on Mars. Kuznetz reported his findings at a Mars Society convention recently held in Toronto.
Another scientist, Gilbert Levin, who experimented on a life-detection instrument sent to Mars aboard a pair of U.S. Viking landers in 1976, said the Viking detected living microorganisms in Mars' soil.
Other scientists disagree. The Viking found no organic matter in 1976, without which there could be no life, they said. But Levin said the Viking's instrument to look for surface organics was just not sensitive enough to detect the small amount of matter constituting Martian organisms.
Levin believes that large regions on Mars are reconstituted daily with moisture. "We know from Viking that the surface on Mars was saturated in water vapor almost every night," he said.
The air just a few feet above the Martian surface is so cold it does not hold water vapor, he explained. That vapor therefore gathers near the surface and is frozen into the soil. As the sun rises and heats up the surface, the frozen water melts and liquefies the soil, making it just right for Martian microorganisms to grow, Levin said.
"I would be surprised if there weren't organisms all over the surface of Mars, just like on Earth," he said.
Kuznetz especially is interested in a system of canyons just south of the Mars' equator, named Valles Marineris, where he believe pools water exist.
"In Valles Marineris, there could be a set of conditions where the sun angle, depth and temperature is just right, and where the atmospheric pressure is just high enough to sustain pools of water," Kuznetz said.
NASA astrobiologist Michael Meyer remains doubtful about the existence of water, at least for long periods of time. There are places on Mars with pressure high enough to support liquid water, he said, it can only exist for a very short time due to high temperature.
"The idea that there would be enough water to support a biosphere is pretty marginal," Meyer said.
Another scientist, Michael Carr, a planetary geologist at the U.S. Geological Survey in Menlo Park, Calif., said the combination of pressure and temperature to sustain liquid water is almost impossible on Mars. Also, below-surface temperatures on the planet are close to a daily average of 215 Kelvin (-72.7 F or -58.1 C), where water is in a deep-freeze state.
"The bottom line is that liquid water is rendered unstable at the Martian equator by both the temperature and the pressure," Carr said.
(Source: Space.com, Inc.)