The latest evidence for methane and other organic chemicals on Mars isn’t the smoking gun for life on Mars that some folks may have been hoping for, but it gives astrobiologists much more to go on.
Readings gathered by NASA’s Curiosity rover show a seasonal cycle in the rise and fall of methane in Mars’ atmosphere, as well as conclusive evidence of organic molecules in drilled-out Martian rocks. The findings are laid out in this week’s issue of the journal Science.
The reports are consistent with past observations, including previous detections of organic molecules as well as measurements of atmospheric methane going back more than a decade. The readings could be explained by past or present biological activity, but non-biological explanations could serve as well.
The big difference this time around is that the signals of organic molecules are orders of magnitude stronger than those previous hints, thanks to more precise, targeted measurements.