July 6, 2012
Curiosity To Dig Deeper For Evidence Of Life On Mars
Lee Rannals for redOrbit.com - Your Universe Online
The findings suggest optimal depths and locations to probe for organic molecules like those that compose living organisms could be reached through the Curiosity rover, which is expected to land on the Red Planet on August 5, 2012.
If there is any evidence of ancient life to be found, NASA's newest rover is a better tool than previously thought, according to Alexander Pavlov of the NASA Goddard Space Flight Center in Greenbelt, Maryland.
The molecules that could be lying just within a shovel's depth could stem from sources like meteorites and volcanoes. Complex organic molecules made up of 10 or more carbon atoms may hint at a strong possibility that the planet used to host life.
The researchers warn in the journal that chances of finding these molecules in the first 0.8-inches of Martian soil is close to zero.
They believe the top layer will absorb a total of 500 million grays of cosmic radiation over the course of a billion years, which is capable of destroying all organic material.
The farther Curiosity digs, say 2 to 4 inches beneath the surface, the amount of radiation reduces tenfold, the authors wrote. The team said that simple organic molecules like a single formaldehyde molecule could exist at that depth.
"Right now the challenge is that past Martian landers haven't seen any organic material whatsoever," Pavlov said. "We know that organic molecules have to be there but we can't find any of them in the soil."
Although the presence of organic material may be exciting, it doesn't mean it originated from the Red Planet itself.
Pavlov said that as Mars revolves around the Sun, it is bombarded by very small meteors and interplanetary dust particles, which have plenty of organic compounds. So, over time, these compounds would have accumulated on the Martian surface.
Curiosity is equipped with drilling technology that will collect, store and analyze samples of Martian material down to about 2 inches below the surface of rock and soil.
Past Martian rovers have only been able to collect loose soil on the top of the surface, which has been directly exposed to cosmic radiation from the Sun.
Scientists found that the best option for the rover is to look at "fresh" craters that are no more than 10 million years old in order to find organic compounds.
The new research indicates that the material will have been near the surface for a short enough period of time that its overall exposure to the radiation would not have wiped out the organic material completely.
"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."