Our relationship with methane is complicated. As natural gas, it’s an efficient fuel that that produces less carbon dioxide than other hydrocarbons. As cow farts, it’s a greenhouse gas often blamed for contributing to climate change. As an abundant substance trapped in permafrost, it gets explosively released when said climate change melts the permafrost in Siberia, creating massive holes. And, as a product of microbial methanogenesis, it’s an important sign that a planet may contain life, or at least have the ingredients to support it. The discovery of methane on Mars in 2004 got the scientific and let’s-move-to-Mars worlds excited. Unfortunately, the party may have been premature – new data shows that all of the Martian methane has disappeared. Who lit a match?
“The presence of methane has been confirmed thanks to the observations of the Planetary Fourier Spectrometer (PFS) on board Mars Express during the past few weeks.”
That was the news in 2004 when the European Space Agency’s ESA Mars Express orbiter detected methane in the Martian atmosphere. The next question was, “Where does this methane come from?” One possibility is from above when organic carbon from solar system dust falls to the surface and reacts with solar radiation to form methane. Another is from below, produced by chemical reactions or live or decayed microorganisms. In 2014, NASA’s Curiosity rover detected a seasonal spike in methane – unexplained but still confirming the presence of the gas.