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Comment by mmanfrin | Hacker News Reader

Question to those with science backgrounds: Would it be possible to 'seed' venus with co2 crunching algae, provided we figured some way of suspending them in the atmosphere above the point where they'd cook to death? Some sort of superlight-algae that could live in the clouds and crunch the CO2 in to O2? It would grow and spread and begin reducing the pressure downwards, allowing it to also eat downwards.

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Didn't the article cover exactly such a proposal, in the 60s, by Carl Sagan? :P

Not really, venus atmosphere is way too thick and heavy. It would takes millions of years. Better would be ice ring on orbit to block sunlight, or bombarding surface with comets.

> It would takes millions of years.

Why? If it works it's exponential so it should be faster than other methods.

I think the problem could be water. The fraction of water vapor on Venus' atmosphere is ~200 times lower, although I don't know if that should factor that Venus' atmosphere would have many times Earth's mass.

I think you need some way of binding the O2 so that it does not just recombine with the C, perhaps by importing large quantities of H2 allowing you to turn the Oxygen into water.

The carbon absorbed in the photosynthesis does not just go free to burn again in oxidation, it stays as a building material for the living creature itself. Considering a positive process, in which more organisms are created (reproduced through mitosis) than those that die, in time the raw quantity of CO₂ should decrease. I'm not sure what to do afterwards with that mass of algae though.

The carbon does not go free because it is bound up in some organic compound, almost always a hydrocarbon (which of course requires Hydrogen) and would still combust at 460 Celsius. Perhaps if this life-form lived exclusively in the upper atmosphere? Then it would just have the problem of getting anything but carbon, oxygen and nitrogen.

You would need to import a lot of water for that.

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