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Phoenix666 writes:

Phys.org:

Reports of methane in the martian atmosphere have been intensely debated because detections have been very sporadic in time and location, and often fell at the limit of the instruments' detection limits. ESA's Mars Express contributed one of the first measurements from orbit in 2004, at that time indicating the presence of methane amounting to 10 ppbv.

Earth-based telescopes have also reported both non-detections and transient measurements up to about 45 ppbv, while NASA's Curiosity rover, exploring Gale Crater since 2012, has suggested a background level of methane that varies with the seasons between about 0.2 and 0.7 ppbv – with some higher level spikes. More recently, Mars Express observed a methane spike one day after one of Curiosity's highest-level readings.

The new results from TGO[*] provide the most detailed global analysis yet, finding an upper limit of 0.05 ppbv, that is, 10–100 times less methane than all previous reported detections. The most precise detection limit of 0.012 ppbv was achieved at 3 km altitude.

[*] TGO: ExoMars Trace Gas Orbiter.

On Earth 95% of atmospheric methane is produced by living things, so the presence of methane in the Martian atmosphere has teased the possibility of life there.

Previously: ExoMars Trace Gas Orbiter Begins Mapping the Atmosphere of Mars Remember the Discovery of Methane in the Martian Atmosphere? Now Scientists Can't Find Any Evidence

Original Submission