By Matthew Polacek

 Atmospheric CH 4 on Earth  Biological sources  Methanogens  Abiotic sources  UV degradation  Geothermal Production  Etc.,

 Early Measurements  Canada-France-Hawaii telescope  NASA IRTF  PFS MEX  TES  Indications of global averages and localized plumes of methane

 Plume findings are questionable  Variability in measurements  Lack of supporting evidence

 Increased accuracy of the TLS at SAM on the Curiosity Rover  Two channel tunable laser spectrometer  Channel 1, 2.78 microns  Channel 2, 3.27 microns

 Note: 1-sol=24 hours 37.5 minutes  Data from 605 sols  11 direct ingest measurements and 2 methane enrichment experiments  Three groups  Low-methane direct ingest  Low-methane enrichment runs  High-methane direct ingest

 Exogenous organics  IDP and comets  Modeling UV/CH 4 conversion rate  2.2 ppbv model vs..7 ppbv actual  High-methane results  No quantitative correlation

 Mars methane detection and variability at Gale crater Christopher R. Webster et al. Science 347, 415 (2015); DOI: /science