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Mars Rovers Sharpen Questions About Livable Conditions
Mars Daily
by Staff Writers
Boston MA (SPX) Feb 18, 2008
Like salt used as a preservative, high concentrations of dissolved minerals in the wet, early-Mars environment known from discoveries by NASA's Opportunity rover may have thwarted any microbes from developing or surviving.
"Not all water is fit to drink," said Andrew Knoll, a member of the rover science team who is a biologist at Harvard University, Cambridge, Mass.
Opportunity and its twin, Spirit, began their fifth year on Mars last month, far surpassing their prime missions of three months. Today, at a meeting of the American Association for the Advancement of Science in Boston, scientists and engineers discussed new observations by the rovers, recent analysis of some earlier discoveries, and perspectives on which lessons from these rovers' successes apply to upcoming missions to Mars.
"The engineering efforts that have enabled the rovers' longevity have tremendously magnified the science return," said Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers' science payload. "All of Spirit's most important findings, such as evidence for hot springs or steam vents, came after the prime mission."
Opportunity spent recent months examining a bright band of rocks around the inner wall of a crater. Scientists previously hypothesized this material might preserve a record of the ground surface from just before the impact that excavated the crater. Inspection suggests that, instead, it was at the top of an underground water table, Squyres reported.
Experiments with simulated Martian conditions and computer modeling are helping researchers refine earlier assessments of whether the long-ago conditions in the Meridiani area studied by Opportunity would have been hospitable to microbes. Chances look slimmer. "At first, we focused on acidity, because the environment would have been very acidic," Knoll said.
"Now, we also appreciate the high salinity of the water when it left behind the minerals Opportunity found. This tightens the noose on the possibility of life."
Conditions may have been more hospitable earlier, with water less briny, but later conditions at Meridiani and elsewhere on the surface of Mars appear to have been less hospitable, Knoll said.
"Life at the Martian surface would have been very challenging for the last 4 billion years. The best hopes for a story of life on Mars are at environments we haven't studied yet -- older ones, subsurface ones," he said.
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What about Extramaphiles?
Use what is abundant and build to last
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What about Extramaphiles?
Extramphiles might never get the chance to evolve in the first place in such an enviroment.
On Earth, there are plenty of enviroments were life can thrive and spread to adapt to all niches. Billions and Billions of bacteria and microorganisms in nice friendly enviroments increase the chances that some will have mutations that help fill wierd niches like Extremaphiles do.
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Well stated, Gregori. That is an important distinction between Mars and Earth. The best possible candidates for finding life on Mars are worse than the worst possible places life can survive in here on earth.
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Panspermia?
Use what is abundant and build to last
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Panspermia?
What about it?
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Life from Earth being blasted to Mars perhaps?
Use what is abundant and build to last
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