Space/Science — HabitableZone

Space/Science » in reply to Very perceptive

Simple Counter Questions
Mark Eby — (archived)

Why can't the Olivine come from volcanic eruptions post dating wet Mars? There is strong evidence Martian volcanism was active far past the supposed wet period.

Why couldn't carbonates formed during a wet period be buried under the lavas discussed above? Being coated with ash then lava would not release the CO2 as it would during crustal recycling on Earth.

Why should CH4 produced subsurface be detectable after passing through highly oxidative top regolith?

Why should an always cold Mars preclude subsurface evolution of life in geothermally heated aquifers? Even Nick seems open to this idea.

Mars has no plate tectonics. This means it's geologic evolution will be drastically different than Earth's. Minerals on Earth that mean one thing in the context of plate tectonics do not necessarily mean the same thing on Mars. We also know Mars should have had far more CO2 in the past. It takes more than a hand wave to judge how much that counter acts a less luminous younger sun. It seems to me that forming where it did Mars should have had even more CO2 per unit mass than the Earth and Venus, but that doesn't seem to match the primordial 7 bar estimates even accounting for differences in surface area per unit mass and gravity.

I don't think your case is concrete at all Gary. It's a credible view, but hardly the only possible interpretation. Again I don't think Nick's model is a slam dunk when there is no existing example of it to verify its validity. I think that as long as life on Mars is reasonably possible NASA is right to pursue that angle as it is one of the fundamental questions of science.

Regards,
Mark

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