2 ms·

The simplest explanation that I can think of is that some form of methane is trapped in geologic formations which periodically release (such as ice), but that t

The simplest explanation that I can think of is that some form of methane is trapped in geologic formations which periodically release (such as ice), but that the mentioned chemical/dust reactions end up sequestering (scrubbing) it in to more solid forms that are harder to detect. Mars would be a much more interesting place if we'd send over enough infrastructure to get mostly autonomous robots going and scaling up local infrastructure for some kind of terra-forming effort.

zamalek 8y ago
A solid [heh] explanation. The methane could simply be absent because of seasons. It has very slightly larger axial tilt than Earth, and a far greater eccentricity. The sun could just be liberating methane from geological formations during the correct conditions (close to the sun, and in summer). Seasons could also affect life (just like it does plants on Earth), but it's never aliens. Mars is currently at its aphelion and the southern ice cap is not receiving sunlight, so anything liberating Methane might be inert. > the mentioned chemical/dust reactions end up sequestering (scrubbing) A good explanation, there is another possibility. Given that CO2 (the main component of the Martian atmosphere) is so much heavier than methane, the minuscule concentration could have floated to the top of the atmosphere and could have been mostly blown away by solar wind. Methane could still be there, just far below the noise floor.
- tdy721 8y ago
  Both of you make good points, I just want to point out that since the mission has been observing mostly during a period of intense dust storm activity. If a dust scrubbing effect is real, the orbiter may still have a chance at detection.
- londons_explore 8y ago
  Methane isn't that much lighter than CO2. Gasses mix really well with even a little wind, which is seems Mars has lots of.

zamalek 8y ago

A solid [heh] explanation. The methane could simply be absent because of seasons. It has very slightly larger axial tilt than Earth, and a far greater eccentricity. The sun could just be liberating methane from geological formations during the correct conditions (close to the sun, and in summer). Seasons could also affect life (just like it does plants on Earth), but it's never aliens. Mars is currently at its aphelion and the southern ice cap is not receiving sunlight, so anything liberating Methane might be inert. > the mentioned chemical/dust reactions end up sequestering (scrubbing) A good explanation, there is another possibility. Given that CO2 (the main component of the Martian atmosphere) is so much heavier than methane, the minuscule concentration could have floated to the top of the atmosphere and could have been mostly blown away by solar wind. Methane could still be there, just far below the noise floor.

tdy721 8y ago
Both of you make good points, I just want to point out that since the mission has been observing mostly during a period of intense dust storm activity. If a dust scrubbing effect is real, the orbiter may still have a chance at detection.
londons_explore 8y ago
Methane isn't that much lighter than CO2. Gasses mix really well with even a little wind, which is seems Mars has lots of.