NASA’s Curiosity rover landed on Mars in August 2012, and its investigations revealed that Mars was once a potentially habitable planet. One of Curiosity’s most exciting observations has been periodic, unusually high abundances of methane in Mars’s atmosphere. Over the past seven years, Curiosity has established a background signal of methane of about 0.41 part per billion by volume (ppbv), and these periodic spikes can increase atmospheric methane to as much as 21 ppbv.
Click here for original story, Scientists turn back time to track methane emissions on Mars
Source: Phys.org