Electrical discharges as a possible source of methane on Mars: Lab simulation

[1] At a concentration of 10–50 ppbv, methane is suggested to be a trace element in the Martian atmosphere. The sharp variations in its concentration observed are difficult to explain using current theories for sources and sinks (be it biotic or abiotic). Here we propose, and demonstrate with a lab simulation, a new production mechanism for methane based on the effect of electrical discharges over iced surfaces. The discharges, caused by electrification of dust devils and sand storms, ionize gaseous CO2 and water molecules and their byproducts recombine to produce methane. Our experimental results show that pulsed electrical discharges over ice samples in a synthetic Martian atmosphere produce about 1.41×1016molecules of methane per joule of applied energy. The results of the electrical discharge experiment were compared with photolysis induced with UV laser radiation and it was found that both produce methane although the efficiency of photolysis is one-third of that of the discharge.