¶Another unattributed Martian gaseous emission. Even as seasonal variations in Martian atmospheric methane remain a mystery (cf. Issue #18), odd variations have been detected in another atmospheric constituent: oxygen. Over the last three Martian years (~5 Earth years), Curiosity’s Sample Analysis at Mars (SAM) portable chemistry lab has detected “significant seasonal and interannual variability [in oxygen levels], suggesting an unknown atmospheric or surface process at work” (paper). “[W]e think it has to be something in the surface soil that changes seasonally because there aren’t enough available oxygen atoms in the atmosphere to create the behavior we see.” NASA’s press release goes into more detail. It’s presumed to be an abiotic process, but, look, we’re not saying it’s aliens… but it’s aliens.