Martian Methane Muddle

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Martian methane muddle reported in an article in news@nature 2 June 2005. Last year scientists found methane in the atmosphere of Mars and many scientists considered this to be proof that there must be life on Mars because on Earth bacteria are the main source of methane in the atmosphere, but others urged caution because methane can be produced by volcanoes and other geochemical processes. One geochemical source of methane is rock named olivine, which when heated under pressure, reacts with water and carbon dioxide to produce methane, and leaves a mineral name serpentine. Olivine was found on Mars several years ago but proponents of the bacterial methane theory claimed that there wasn't enough of it to go on producing methane for the 4.5 billion years Mars is believed to have existed.

This claim prompted two groups of geologists to estimate how much olivine would be needed, and how much actually exists on Mars. Chris Oze and Mukul Sharma of Darthmouth College, New Hampshire calculated that 80,000 tons of olivine would need to be converted to serpentine per year. This would require the equivalent of a 50cm thick layer a few kilometres deep in the crust spread over the whole planet. Oze and Sharma believe this is possible. Phil Christensen of Arizona State University has analysed data from the Mars Odyssey spacecraft that is orbiting Mars. He found a mass of olivine the size of Cuba that looks as if it had been forced to the surface by volcanic activity, indicating there may be much more below the ground. Christensen also believes there is enough olivine to explain the methane.

Editorial Comment: If Mars has only been in existence for thousands, rather than billions of years there is more than enough olivine to account for the amount of methane that has been found on the red planet. The presence of olivine also indicates that the environment on Mars is too cold and dry for life. Olivine weathers within a few months if exposed to conditions that are warm and moist enough to support life. Both situations are no problem if you accept the short Biblical timetable rather than the vast aeons of the evolutionary timescale. (Ref. astrobiology, geochemistry, planets)

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