Evidence for ancient life on Mars could be just below surface, new study finds (+video)
Researchers say that evidence of ancient life on Mars could take the form of simple organic molecules lying just beneath the Red Planet's surface, and that it could be detectable by NASA's newest rover, which is scheduled to touch down on the planet next month.
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The new study offers suggestions for where Curiosity could begin its search.Skip to next paragraph
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Previous studies focused on the maximum depth that cosmic radiation can reach, Pavlov said, since organic molecules below that point – approximately 5 feet (1.5 meters) – conceivably could survive unharmed for billions of years. But drilling to that depth using existing rover technology would be impractical.
In the new research, the scientists examined a range of more-attainable depths and modeled the accumulation of cosmic ray radiation and its effects on organic molecules. To reach their results, researchers looked at soil and rock composition on Mars, changes in the planet's atmospheric density over time, and the various energy levels of cosmic rays.
The scientists found that "fresh" craters — ones no more than 10 million years old — are optimal sites for Curiosity to investigate, since radiation levels in these young surface features may have lower radiation levels near the surface. If so, more complex molecules, such as amino acids, could remain intact, the researchers said.
"When you have a chance to drill, don't waste it on perfectly preserved" landscapes, Pavlov said. "You want to go to fresh craters because there's probably a better chance to detect complex organic molecules. Let nature work for you."
Curiosity is scheduled to land in the 3.5-billion-year-old Gale crater. Pavlov and his colleagues hope the results of their study will help mission managers decide where to drill once the $2.5 billion rover touches down.
Detailed results of the study will appear in the July 7 issue of the journal Geophysical Research Letters.
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