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The article is looking strictly at plant survival ("could be made habitable to photosynthetic life"). For that, the "usable pressure" is much lower.
by azernik 7y ago
The article is looking strictly at plant survival ("could be made habitable to photosynthetic life"). For that, the "usable pressure" is much lower.
- bayesian_horse 7y agoYes, that would be one explanation. Still, the thin atmosphere of mars would prevent any liquid water or plant life. So they must be talking about at least some more pressure.
- azernik 7y agoYup - they specifically talk about partial pressures of a few gasses as needing to be brought up. But holding in just the partial pressure of those two is a lot easier than holding in a full atmosphere of pressure.
- bayesian_horse 7y agoI don't think it works that way. Plants generally also need oxygen, if only at night or relatively little. So we're basically up to Oxygen and CO2, and Nitrogen might not be entirely avoidable either depending on how the plants are supposed to get their Nitrogen. Water vapor will also be necessary or unavoidable... The pressure needs to be high enough to prevent boiling and less dramatic effects on water or similar matter. There's a reason nothing grows above a certain altitude. That's why I asked about a usable atmosphere... And anyone living on Mars would probably have acclimated to a certain atmospheric pressure. Maybe it is beneficial for them to be "altitude adapted" or maybe it's not (oxygen capacity vs risk of embolisms).