Plumes of methane identified on Mars

摘要

More than four years after researchers first said they had found methane gas on Mars, a scientist claims that he has "nailed" the controversial detection and identified key sources of the gas. On Earth, methane is mostly biological in origin; on Mars, it could signal microbes living deep underground. The latest work suggests that martian methane is concentrated in both space and time - at a handful of hotspots hundreds of kilometres across, plumes of methane bloom and dissipate in less than a year. News of the detection is rippling through the Mars community just months before a destination is picked for the Mars Science Laboratory (MSL), the US$2-billion rover that is due to launch in 2009. It will carry an instrument that could both detect trace amounts of methane and help discern whether it is of biological or geological origin. One of the proposed methane plumes blankets one of the seven possible landing sites: Nili Fossae, which was given a middling ranking by the science community after a September evaluation that did not consider the emerging methane results.