page_title: Mars general circulation model
section_title: Methane on Mars
hierarchical_section_title: Mars general circulation model / Methane on Mars
caption_attribution_description: English: PIA22328: Mars' Mysterious Methane https://photojournal.jpl.nasa.gov/catalog/PIA22328 NASA's Curiosity rover used an instrument called SAM (Sample Analysis at Mars) to detect seasonal changes in atmospheric methane in Gale Crater. The methane signal has been observed for nearly three Martian years (nearly six Earth years), peaking each summer. This work was funded by NASA's Mars Exploration Program for the agency's Science Mission Directorate (SMD) in Washington. Goddard provided the SAM instrument. JPL built the rover and manages the project for SMD. More information about Curiosity is online at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/.
context_page_description: The Mars general circulation model is the result of a research project by NASA to understand the nature of the general circulation of the atmosphere of Mars, how that circulation is driven and how it affects the climate of Mars in the long term.
context_section_description: The Martian atmosphere contains 10 nmol/mol methane (CH₄). In 2014, NASA reported that the Curiosity rover detected a tenfold increase ('spike') in methane in the atmosphere around it in late 2013 and early 2014. Four measurements taken over two months in this period averaged 7.2 ppb, implying that Mars is episodically producing or releasing methane from an unknown source. Before and after that, readings averaged around one-tenth that level. On 7 June 2018, NASA announced a cyclical seasonal variation in the background level of atmospheric methane.
  The principal candidates for the origin of Mars' methane include non-biological processes such as water-rock reactions, radiolysis of water, and pyrite formation, all of which produce H₂ that could then generate methane and other hydrocarbons via Fischer–Tropsch synthesis with CO and CO₂. It has also been shown that methane could be produced by a process involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars.
  Living microorganisms, such as methanogens, are another possible source, but no evidence for the presence of such organisms has been found on Mars.
caption: Curiosity rover detected a cyclical seasonal variation in atmospheric methane.
exif: {}