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On the atmosphere point that's one thing that isn't as much of a problem. Plants can breath in Mars atmosphere and pressure. Sure the pressure is 0.6% comparin

On the atmosphere point that's one thing that isn't as much of a problem. Plants can breath in Mars atmosphere and pressure. Sure the pressure is 0.6% comparing Mars/Earth but the CO2% is 0.04% when comparing Earth/Mars. In other words the partial pressure of CO2 on Mars is actually higher than on Earth. Which is great for CO2 breathing plants. If the temperature was raised a plant would have more CO2 available even with the much lower pressure than on Earth. Indeed experiments with 95% CO2 (matching Mars) and 6millibars pressure (matching Mars) and with martian soil showed that Potato's grow fine. https://cipotato.org/blog/indicators-show-potatoes-can-grow-mars/ https://cipotato.org/blog/indicators-show-potatoes-can-grow-... The only adjustment was temperature!

wollstonecraft 6y ago
But how is this possible? Water has a vapor pressure of 23 millibars at 20 C, meaning water would boil from the leaves.
- AnotherGoodName 6y ago
  It boils but it takes many hours to boil off completely. Here's a study of the time taken to evaporate water in a near vacuum at 20C: https://www.hou.usra.edu/meetings/lpsc2014/pdf/2060.pdf https://www.hou.usra.edu/meetings/lpsc2014/pdf/2060.pdf 25ml of liquid water takes 3 hours to completely boil off under vacuum. Less if the water is mixed in with other substances (eg. soil). The inner structure of the plant itself is capable of trapping water to an even greater extent. To the point where water directly boiling off the plant directly isn't significant. Note that this was simulating asteroid conditions. Mars is slightly better at retaining water since it has slightly more pressure. This is why it's pretty likely that we're seeing flowing water on Mars each summer: https://www.nasa.gov/press-release/nasa-confirms-evidence-that-liquid-water-flows-on-today-s-mars https://www.nasa.gov/press-release/nasa-confirms-evidence-th...

wollstonecraft 6y ago

But how is this possible? Water has a vapor pressure of 23 millibars at 20 C, meaning water would boil from the leaves.

AnotherGoodName 6y ago
It boils but it takes many hours to boil off completely. Here's a study of the time taken to evaporate water in a near vacuum at 20C: https://www.hou.usra.edu/meetings/lpsc2014/pdf/2060.pdf https://www.hou.usra.edu/meetings/lpsc2014/pdf/2060.pdf 25ml of liquid water takes 3 hours to completely boil off under vacuum. Less if the water is mixed in with other substances (eg. soil). The inner structure of the plant itself is capable of trapping water to an even greater extent. To the point where water directly boiling off the plant directly isn't significant. Note that this was simulating asteroid conditions. Mars is slightly better at retaining water since it has slightly more pressure. This is why it's pretty likely that we're seeing flowing water on Mars each summer: https://www.nasa.gov/press-release/nasa-confirms-evidence-that-liquid-water-flows-on-today-s-mars https://www.nasa.gov/press-release/nasa-confirms-evidence-th...