Hmm. The article says that NASA scientists "believe" that the methane they've detected comes from microbes just below the Martian surface. The
article also states that the only other possible source of the methane would be volcanic activity, but that there are no known active volcanos on
Mars.
But we know that methane exists in trace amounts on Jupiter and in greater amounts on Uranus and Neptune.
The third most abundant constituent of the Uranian atmosphere is methane (CH4). Methane possesses prominent absorption bands in the visible and
near-infrared (IR) making Uranus aquamarine or cyan in color. Methane molecules account for 2.3% of the atmosphere by molar fraction below the methane
cloud deck at the pressure level of 1.3 bar (130 kPa);.
en.wikipedia.org...
As with Uranus, this absorption of red light by the atmospheric methane is part of what gives Neptune its blue hue, although Neptune's vivid
azure differs from Uranus's milder aquamarine. Since Neptune's atmospheric methane content is similar to that of Uranus, some unknown atmospheric
constituent is thought to contribute to Neptune's colour.
en.wikipedia.org...
Methane, when in the presence of free oxygen AND ultraviolet radiation, breaks down into carbon monoxide, hydrogen and water.
CH4 + O2 = CO + H2 + H2O
There are trace amounts of oxygen on Mars which leads NASA scientists to believe that the detected methane must have been produced recently. However,
this is interesting:
Several researchers claim to have detected methane in the Martian atmosphere with a concentration of about 10 ppb by volume. Since methane is an
unstable gas that is broken down by ultraviolet radiation, typically lasting about 340 years in the Martian atmosphere, its presence would indicate a
current or recent source of the gas on the planet. Volcanic activity, cometary impacts, and the presence of methanogenic microbial life forms are
among possible sources. It was recently pointed out that methane could also be produced by a non-biological process called serpentinization
involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars.
en.wikipedia.org...
In one of the four major serpentine reactions, olivine, water and carbon dioxide react to form serpentinite, magnetite and methane. This reaction
occurs continuously on Earth, but mainly at the ocean floors.
Serpentinization is a geological low-temperature metamorphic process involving heat and water in which low-silica mafic and ultramafic rocks are
oxidized and hydrolyzed with water into serpentinite.
....
In the process large amounts of water are absorbed into the rock increasing the volume and destroying the structure.
....
Rock temperatures can be raised by about 260 oC, providing an energy source for formation of non-volcanic hydrothermal vents. The magnetite-forming
chemical reactions produce hydrogen gas. Sulfates and carbonates are reduced and form methane and hydrogen sulfide. The hydrogen, methane, and
hydrogen sulfide provide energy sources for deep sea chemotroph microorganisms.
en.wikipedia.org...
Given all of this information, I'm a-gonna go out on a limb and handicap this thing.
Probable source of Martian methane: Life.
[edit on 15-1-2009 by Tuning Spork]
