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NASA reports that terrestrial microbes that hitch a ride to Mars on spacecraft may be able to survive under special circumstances, according to a new laboratory study. The research suggests scientists should take extra care when analyzing potential signs of life during future missions to the Red Planet.
Most spacecraft that touch down on Mars have not been thoroughly sterilized by heat or radioactivity - so they carry with them living microbes from Earth. But Mars's thin atmosphere allows such intense ultraviolet radiation to reach the planet's surface - triple that found on Earth - that any life inadvertently carried on the spacecraft is thought to be wiped out quickly. Indeed, Martian-level doses of UV radiation have destroyed some microbe species in just seconds in laboratory tests.
But now, an international team has tested the endurance of a particularly hardy type of blue-green alga - or cyanobacterium - that thrives in dry deserts from Antarctica to Israel. The resilient bacterium, called Chroococcidiopsis sp. 029, was chosen as a "worst-case scenario" for contamination of the planet.
The team found that dormant spores of the bacterium had mostly died after five minutes of Martian UV exposure. However, the bacteria were able to stay alive if they were shielded by just 1 millimeter of soil during the tests, which ran for up to 24 hours. Making a living under such a protective coating, the bacteria "could survive - and potentially grow - under the high Martian UV flux if water and nutrient requirements for growth were met". "We think there are places on Mars where Earth life could make a living," says John Rummel, NASA's planetary protection officer in DC, who is charged with preventing microbes from contaminating worlds beyond Earth. He says this study shows "even the toughest stuff doesn't survive for long" on the surface of spacecraft, but he says live microbes probably do take shelter within the spacecraft bodies.
Martian gullies that may periodically be flooded with liquid water, or areas around the poles, where "microbes and ice could make a happy partnership", Rummel told New Scientist. Snip Thanks to http://www.newscientistspace.com/channel/...
Editor's Note: In 1976, Mars Viking Lander's
Life Probes and Gilbert V. Levin's Labeled Release Life Detection Devices found microbial life on Mars. I spoke with Dr. Levin who is more positive than ever that life was found.
This color -enhanced view of Big Joe boulder at the Viking 1 lander site (SOL 556) with a green covering and a cap of material on top of the boulder missing from surrounding rocks. Courtesy of Lunar and Planetary Institute/Texas. Viking likely took photos of blue-green alga - or cyanobacterium on Mars in 1976. In my opinion Mars has water, plant life and evidence of ancient structures. NASA may deny life on Mars because it is an ideal site for colonization. June through August, Earth is catching up with Mars bringing us closer for at least 5000 years. It is slowly becoming the brightest star or planet in the night sky.
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