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Do we know how much CO2 there actually is on Mars?
I have read 75mb or so in the poles and then an unknown amount in the regolith. But what if there's no CO2 in the regolith and this 75mb is it. In this case, we could convert it all to oxygen and it still wouldn't be a breathable atmosphere (although I believe bodily fluids wouldn't boil, so maybe with nanotech it could be).
So in this case, why not split water from the ice caps to release O2. I don't know what we'd do with the hydrogen: ideally not send it into space; it's valuable. I have read on this forum that 100mb O2 and 50mb CO2 is a breathable mixture.
In a sense if we just get enough O2 into the atmosphere for breathing, the planet is already terraformed even without warming. You'd need to wrap up warm, but you need to wrap up warm in Canada. No one wants to "terraform" Canada, do they? Admittedly Antarctica is a better analog.
However, if there is fluorine mineral on Mars, which I imagine there virtually has to be, then we can release this as the correct cocktail of fluorocarbons to warm the planet.
I suspect the lack of nitrogen will prevent much wildlife from growing (unless the soil is really full of nitrates: anyone know?), but we should still be able to get nitrates to grow crops either from geological nitrate deposits (which will probably exist: they do on Earth), or if necessary via e.g. the Haber process from the Martian atmosphere. A lack of wildlife even after "terraformation" could be desirable, in the sense that it will preserve the beauty of the "natural" Mars. So I am not worried about nitrogen either way. It's good if it's there. If not, that's still OK as we can fix what we need ourselves.
The point of this approach is that (other than postulating the presence of fluorine; how can there not be fluorine?) it does not require any particular elements to be present. Just lots and lots of energy, which a future society will have access to, either from very efficient, cheap solar power or (more likely, I think) from fusion.
Actually, I'm assuming there's enough oxygen in the ice of the polar ice caps for this? I have no figures or intuitive grasp at present. That must be correct, though?
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Do we know how much CO2 there actually is on Mars?
I have read 75mb or so in the poles and then an unknown amount in the regolith. ...
Hi workstation.
There is almost certainly CO2 in the regolith. Various clays absorb CO2 when cold and there is lots of clay on Mars. (These have been detected directly and they are formed when basalt weathers. And there is LOTS of basalt on Mars.) There is also likely to be plenty of CO2 dissolved in ice (a clathrate). The polar caps do not have anywhere near 75 mBar of CO2 unless you count clathrates. (And I've seen no figures on how much CO2 is dissolved in that ice.)
As for how much CO2 Mars has, we only have guesses. MY guess is lots. Mars had a warm, wet period back when the sun was only 70% as warm as it is now, and people have calculated that Mars would have needed about 4 Bars of CO2 to have that temperature. CO2 is too heavy for Mars to lose to space so its all got to be there somewhere. That does not mean it will be easy to get at it tho.
So in this case, why not split water from the ice caps to release O2. ...
The reason is energy cost. If we have enough energy to do that, it would be cheaper to build perfluorocarbons and heat the planet and let plants split CO2.
However, if there is fluorine mineral on Mars, ...
Mars almost certainly has fluorine ores (they are concentrated in volcanic melts) but no-one has actually detected any fluorine on Mars. However, it is a very rare substance and no one has looked for it very hard.
I suspect the lack of nitrogen will prevent much wildlife from growing (unless the soil is really full of nitrates: anyone know?), ...
No one has suggested any reason why Mars would have not started off with its share of N2. However, lightning and cosmic rays create nitrogen compounds (various nitrates) which leach into the soil. (Life recirculates these compounds on Earth.) Some deserts on Earth have extremely concentrated nitrate deposits caused by thousands of years of lightning. I expect Mars will have vast nitrate deposits with a certainty approaching 100%. The question is: if we get a bacteria biosphere going, will the bacteria find these nitrates accessible enough to free a significant amount into the air? No one knows this.
Actually, I'm assuming there's enough oxygen in the ice of the polar ice caps for this? I have no figures or intuitive grasp at present. That must be correct, though?
I can't see it being a problem as it is very likely that there will be enough O2 for a breathable atmosphere in the CO2, and it is very likely that there will be enough CO2 once the soil is warmed by 50 degrees C.
Warm regards, Rick
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The polar caps do not have anywhere near 75 mBar of CO2 unless you count clathrates. (And I've seen no figures on how much CO2 is dissolved in that ice.)
Do we know how much pressure we'd get from just the pure CO2 in the ice caps? Somebody must know this, surely? We know the depth and we have pictures of the extent.
I suppose the hard limit of what we need is 63mb to avoid vacuum effects. If we can get that, we just need some way to oxygenate the blood. I suspect this could be done with a breathing mask and nanotechnology in the form of artificial red blood cells. (maybe)
So in this case, why not split water from the ice caps to release O2. ...
The reason is energy cost. If we have enough energy to do that, it would be cheaper to build perfluorocarbons and heat the planet and let plants split CO2.
Yes, but that would take a very long time (I was suggesting making perfluorocarbons as well as oxygen btw). My point is simply that the only technological advance we need to make oxygen is an advanced form of energy generation. These are in the works e.g. fusion. If we had a vast supply of electricity, it would be "easy" technology.
No one has suggested any reason why Mars would have not started off with its share of N2. However, lightning and cosmic rays create nitrogen compounds (various nitrates) which leach into the soil. (Life recirculates these compounds on Earth.) Some deserts on Earth have extremely concentrated nitrate deposits caused by thousands of years of lightning. I expect Mars will have vast nitrate deposits with a certainty approaching 100%. The question is: if we get a bacteria biosphere going, will the bacteria find these nitrates accessible enough to free a significant amount into the air? No one knows this.
That's good, I think, if it turns out to be true. We don't need nitrogen in the atmosphere. We only really need it in accessible forms in the soil for plants.
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Do we know how much pressure we'd get from just the pure CO2 in the ice caps? Somebody must know this, surely? We know the depth and we have pictures of the extent. ...
Hi workstation, everyone.
The number I usually see quoted is 14 mBars.
Rick
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