August 6, 2009
Martian Mystery Continues
According to a recent analysis, it appears that methane on Mars is produced and destroyed at a faster rate than on Earth.
Researchers in Paris used a computer program that models the Martian planet to simulate observations made from Earth.The program showed that gas is unevenly distributed in Mars' atmosphere and fluctuates with the seasons.
The presence of methane on Mars means its origin could have been geological activity, or possibly life.
Franck Lefevre and Francois Forget from the Universite Pierre et Marie describe how they used the computer model in the journal Nature.
According to Dr. Lefevre, the chemistry of the atmosphere on Mars is still a mystery.
"We put the dynamics and chemistry as we know it in the model and tried to match the measurements, to reproduce the uneven distribution they saw from Earth," Dr. Lefevre told BBC News.
"The problem is if we just take into account the photochemistry as we know it on Earth and if we put it in the model, then we cannot reproduce the model and that was a surprise."
"The current chemistry as we know it is not consistent with the measurements of methane on Mars. There is something else going on, something that lowers the methane lifetime by a factor of 600. So if the measurements are correct, we must be missing something quite important," he added.
According to Dr. Lefevre, the data shows that faster loss for methane on Mars means there must also be much stronger production of the gas.
"It's a real challenge to measure methane on Mars from Earth and we've got only one example of this uneven distribution," he said.
The French researchers used data gathered by an American team with a technique called infrared spectroscopy. The Americans monitored 90% of the Martian surface and published their findings last January in the journal Science.
"Plumes" of methane were discovered on the Red Planet in 2003. One of the plumes was estimated to contain nearly 19,000 tones of the gas.
According to Dr. Michael Mumma, director of Nasa's Goddard Center for Astrobiology, it is vital to know how methane was destroyed on Mars to explain how the gas is produced and destroyed at such a fast rate.
Dr. Mumma believes geology alone could be the cause of the methane.
If the gas is produced through geological activity, it could originate from serpentinization.
Serpentinization occurs at low temperatures when rocks rich in olivine and pyroxene chemically react with water, producing methane.
Dr. Mumma's team will begin another study of Mars in December.
According to Dr. Lefevre, if the theories about the Martian surface are confirmed, it could mean the surface is hostile for organics. This would not fully exclude the possibility of life below the ground.
The $2.3 billion Mars Science Laboratory, also called "Curiosity," will be sent to the planet in 2011
The European and US space agencies could then send a European orbiter to the Red Planet in 2016 to track down the sources of methane.
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