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  1. - Top - End - #61
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Forum Explorer View Post
    Or just frozen hydrongen. That would react with the Carbon Dioxide to create water and lower the amount of CO2 that way.
    Getting just carbon and water out of that reaction seems extremely unlikely. You'd probably end up with complex carbohydrates, so maybe you'd cover the surface of the planet with a crust of sugar!
    Last edited by factotum; 2021-02-17 at 01:57 AM.

  2. - Top - End - #62
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Forum Explorer View Post
    I'm pretty sure that'll be small potatoes compared to the heat we have to shed in the first place.
    One small potato at sufficient velocity could vaporize the Earth.

    Quote Originally Posted by factotum View Post
    Getting just carbon and water out of that reaction seems extremely unlikely. You'd probably end up with complex carbohydrates, so maybe you'd cover the surface of the planet with a crust of sugar!
    Don't tell Galactus that we have a frosted planet.

  3. - Top - End - #63
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by factotum View Post
    Getting just carbon and water out of that reaction seems extremely unlikely. You'd probably end up with complex carbohydrates, so maybe you'd cover the surface of the planet with a crust of sugar!
    Sure, there'd be a bunch of byproducts, that's not really a bad thing when the goal is to remove as much CO2 as possible from the atmosphere. I think one of the proposals suggested getting a bunch of minerals launched into Venus as well to cause other reactions.

    Quote Originally Posted by Nifft View Post
    One small potato at sufficient velocity could vaporize the Earth.
    Not really. Even at lightspeed, it would only cause a massive fusion explosion. Which might wipe out a city if you're unlucky, but that doesn't matter one whit to the Earth as a whole.

    Now admittedly, I'm talking about throwing an entire moon's worth of matter, which is a lot more massive than a potato. But on the other hand, there's no reason to even try and get it to a percent of lightspeed. Furthermore we don't really care about any damage done. So long as we remove enough CO2 for heat to actually begin dissipating, any added heat is ultimately irrelevant.
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  4. - Top - End - #64
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Fat Rooster View Post
    Incidentally, I lol-ed at the section talking about the viability of feeding other micro-organisms the mass produced. It jumped out at me as one of those translation things where they compare what is in the paper to what actually happened:

    "We then tested the viability of feeding other micro-organisms" = "Our sample then went mouldy"

    With more reading it sounds like this was more deliberate than that, but made me laugh anyway.
    Upon rereading it reminded me of how to translate standard academic paper phrases.
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  5. - Top - End - #65
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    Default Re: Venus or Mars for terraforming and colonisation?

    Don't forget "At this stage, the sample size was reduced" means, at least in botanical research "And then one of my student assistants kicked over one of the pots while watering and spilled everything".
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  6. - Top - End - #66
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by halfeye View Post
    I strongly disagree. Most of the pressure is due to CO2. Plants convert CO2 to sugars.
    So the solution is somehow cover the entire planet in a 50 meter thick layer of sugar.
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Forum Explorer View Post
    Not really. Even at lightspeed, it would only cause a massive fusion explosion. Which might wipe out a city if you're unlucky, but that doesn't matter one whit to the Earth as a whole.
    If you actually did manage to get a potato to lightspeed (breaking a number of laws of physics to do so) then it would literally have infinite kinetic energy and would entirely destroy the Earth--and the rest of the universe as well, but let's not worry too much about that part. Assuming you actually mean some "arbitrarily close to lightspeed" value then you're still wrong, because you can literally keep adding kinetic energy to make the thing get closer and closer to lightspeed without any upper limit. If youure just thinking "Well, it's 1/2 m * v ^2 and we know m and v, so..." then you're forgetting mass dilation, which means the mass of the potato increases the closer to lightspeed it gets.

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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by factotum View Post
    If you actually did manage to get a potato to lightspeed (breaking a number of laws of physics to do so) then it would literally have infinite kinetic energy
    The Prandtl-Glauert singularity says "hi".

    Seriously, no matter how good the math is, it seems arrogant to assume we know with absolute certainty how effects with lightspeed work, considering we know a photon goes that fast and how much we don't know about photons, at the very least.

    Now, I'm not about to start arguing that it's possible for a particle with mass to reach or Einstein was wrong or anything, but I'm perfectly willing to entertain thought experiments of what, by all of our understanding, should be impossible and ignoring the "well you can't" aspects for the sake of the thought experiment.
    Last edited by Peelee; 2021-02-17 at 09:37 AM.
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  9. - Top - End - #69
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by factotum View Post
    If you actually did manage to get a potato to lightspeed (breaking a number of laws of physics to do so) then it would literally have infinite kinetic energy and would entirely destroy the Earth--and the rest of the universe as well, but let's not worry too much about that part. Assuming you actually mean some "arbitrarily close to lightspeed" value then you're still wrong, because you can literally keep adding kinetic energy to make the thing get closer and closer to lightspeed without any upper limit. If youure just thinking "Well, it's 1/2 m * v ^2 and we know m and v, so..." then you're forgetting mass dilation, which means the mass of the potato increases the closer to lightspeed it gets.
    Would a superfast potato have enough (relative) time to interact with regular matter in a meaningful way?
    Wouldnt its atoms just move unhindered through the Earth? Subatomic space is mostly empty. Before meaningful forces could act, most particles would be past each other.
    Shooting a bullet at a paper sheet doesn't disintegrate the whole papersheet. It just punches holes where it hits.

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    Default Re: Venus or Mars for terraforming and colonisation?

    Of course you can always ignore well known and proven laws of physics for hypothetical scenarios. But doing any calculations with equations you know to be wrong to compare results doesn't provide any insights into anything.
    If you throw out some fundamental assumptions, you need to throw out everything and the outcome is simply fantasy.
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Peelee View Post
    considering we know a photon goes that fast and how much we don't know about photons, at the very least.
    Yeah, but one critical thing we *do* know about photons is that they don't have mass, so it's not comparable to Forum Explorer's potato.

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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by factotum View Post
    Yeah, but one critical thing we *do* know about photons is that they don't have mass, so it's not comparable to Forum Explorer's potato.
    A mere triviality, fixed by two simple lines: Consider a massless potato moving at the speed of light. The rest is left as an exercise for the reader.

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  13. - Top - End - #73
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by factotum View Post
    If you actually did manage to get a potato to lightspeed (breaking a number of laws of physics to do so) then it would literally have infinite kinetic energy and would entirely destroy the Earth--and the rest of the universe as well, but let's not worry too much about that part. Assuming you actually mean some "arbitrarily close to lightspeed" value then you're still wrong, because you can literally keep adding kinetic energy to make the thing get closer and closer to lightspeed without any upper limit. If youure just thinking "Well, it's 1/2 m * v ^2 and we know m and v, so..." then you're forgetting mass dilation, which means the mass of the potato increases the closer to lightspeed it gets.
    I thought that as high velocity projectiles very often leave a clean, narrow hole and do not deposit all that much energy - as there is no time for it to propagate any further than the direct path of the projectile - it would not destroy the whole planet. However, there was a What if? article dedicated to such a problem but with a much larger impactor. The point is that with enough nines after the dot you can reduce the Earth to a rapidly expanding gas cloud.

    Quote Originally Posted by Peelee View Post
    The Prandtl-Glauert singularity says "hi".

    Seriously, no matter how good the math is, it seems arrogant to assume we know with absolute certainty how effects with lightspeed work, considering we know a photon goes that fast and how much we don't know about photons, at the very least.

    Now, I'm not about to start arguing that it's possible for a particle with mass to reach or Einstein was wrong or anything, but I'm perfectly willing to entertain thought experiments of what, by all of our understanding, should be impossible and ignoring the "well you can't" aspects for the sake of the thought experiment.
    Actually, we know pretty well, how matter behaves at high relativistic speeds as we commonly accelerate protons or heavy ions to very significant fractions of c. For example LHC accelerates protons to 0.999999991c.
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  14. - Top - End - #74
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Radar View Post
    Actually, we know pretty well, how matter behaves at high relativistic speeds as we commonly accelerate protons or heavy ions to very significant fractions of c. For example LHC accelerates protons to 0.999999991c.
    That last 0.000000001 is the real trick, isn't it?

    For reals, though, that's pretty awesome. I knew we got to somewhere like 0.000something Kelvin up in Canada, but didn't know how close to c we've gotten.
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Peelee View Post
    The Prandtl-Glauert singularity says "hi".

    Seriously, no matter how good the math is, it seems arrogant to assume we know with absolute certainty how effects with lightspeed work, considering we know a photon goes that fast and how much we don't know about photons, at the very least.

    Now, I'm not about to start arguing that it's possible for a particle with mass to reach or Einstein was wrong or anything, but I'm perfectly willing to entertain thought experiments of what, by all of our understanding, should be impossible and ignoring the "well you can't" aspects for the sake of the thought experiment.
    Iron atom nucluei with 99.9999999999% of the speed of light crash into the earth all the time. We know a bit about what happens, sometimes they go right through the entire planet. Sometimes they crash into an atom somewhere along the way and scatter into many high energy particles.
    If we could accelerate an entire potato to the same speed and direct it at the Earth it would be devastating for all life on the surface.
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Yora View Post
    So the solution is somehow cover the entire planet in a 50 meter thick layer of sugar.
    A 100 metre thick layer of plant matter, yeah. Eventually, peat and then coal. The point is carbon isn't a gas, it's oxides are, separate out the oxygen, lots of carbon. There's probably something to be done with all the oxygen, maybe burn rocks?
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    Default Re: Venus or Mars for terraforming and colonisation?

    The radiation hitting Venus is double what Earth gets. I don't know that an Earth atmosphere would be sufficient to protect human life there.
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    Quote Originally Posted by Tvtyrant View Post
    The radiation hitting Venus is double what Earth gets. I don't know that an Earth atmosphere would be sufficient to protect human life there.
    I'm sort of thinking leave some of the sun-shield in place. I don't know that much about the non-solar radiation.

    The goldilocks zone is where water is liquid. We're currently pretty near the cold end of that, Venus is probably near the hot end or outside it, we'd be uncomfortable at 90 degrees C, but at the thermal vents there is life at that temperature, and if we got the temperature down below that once, we could probably keep it down. Mars is always going to be cold.
    Last edited by halfeye; 2021-02-17 at 02:23 PM.
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by factotum View Post
    If you actually did manage to get a potato to lightspeed (breaking a number of laws of physics to do so) then it would literally have infinite kinetic energy and would entirely destroy the Earth--and the rest of the universe as well, but let's not worry too much about that part. Assuming you actually mean some "arbitrarily close to lightspeed" value then you're still wrong, because you can literally keep adding kinetic energy to make the thing get closer and closer to lightspeed without any upper limit. If youure just thinking "Well, it's 1/2 m * v ^2 and we know m and v, so..." then you're forgetting mass dilation, which means the mass of the potato increases the closer to lightspeed it gets.
    Right, I didn't literally mean lightspeed because of the whole impossibility of it. I'll also admit that I drastically underestimated how much energy is gained going from 0.9c to 0.9999c.

    However, it's completely irrelevant to the discussion and my idea in the first place. There's no reason to accelerate an object that fast when bombarding Venus. It would be a waste of energy to do so and it would make terraforming Venus harder.

    Quote Originally Posted by factotum View Post
    Yeah, but one critical thing we *do* know about photons is that they don't have mass, so it's not comparable to Forum Explorer's potato.
    It's not my potato! I didn't bring up the concept in the first place.
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    Quote Originally Posted by Forum Explorer View Post
    Right, I didn't literally mean lightspeed because of the whole impossibility of it.
    However, you did literally write "lightspeed".
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    Quote Originally Posted by Forum Explorer View Post
    Right, I didn't literally mean lightspeed because of the whole impossibility of it. I'll also admit that I drastically underestimated how much energy is gained going from 0.9c to 0.9999c.

    However, it's completely irrelevant to the discussion and my idea in the first place. There's no reason to accelerate an object that fast when bombarding Venus. It would be a waste of energy to do so and it would make terraforming Venus harder.
    True, we do not need such ludicrous speeds.

    Quote Originally Posted by Forum Explorer View Post
    It's not my potato!
    It seems that this potato got pretty hot from traveling so fast.
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    Quote Originally Posted by Forum Explorer View Post
    It's not my potato! I didn't bring up the concept in the first place.
    We can call it Peelee's Potato if you'd like.

    Also,i got fifty bucks for whoever can get a concept called "Peelee's Potato" published into a major reputable physics textbook.
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    We do know a bit about how relativistic particle collisions impact humans due to an accident in the Soviet Union.
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    Quote Originally Posted by Yora View Post
    So the solution is somehow cover the entire planet in a 50 meter thick layer of sugar.
    Just how different is that from topsoil? I'd expect part of that "layer of carbs" to be forest and undergrowth, but soil would have to make up a large part of it.

    Venus is presumably far easier to terraform: you already have plenty of materials life needs to build an Earth-like plantet (in the clouds, the surface can wait until the clouds change a lot). Just expect it to take centuries or longer.

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    Default Re: Venus or Mars for terraforming and colonisation?

    The problem with turning most of the atmosphere into biomass is that we first would have to reduce the temperature down from over 400 degrees. Cellulose and hydrocarbons ignite at those temperatures, and any kinds of plants to turn CO2 into cellulose require liquid water. Not to mention proteins which break down at a measly 40 degrees.

    While there are extremophile microbes on Earth, the extreme temperatures they can survive in are in the range of 80 to 120 degrees. And they still require liquid water.

    Populating Venus with life to make it habitable for life doesn't work.

    I don't know if machines are plausible that use solar power to convert CO2 and local minerals into a compound that is stable up to 500 degrees. But it would be incredibly slow.
    Last edited by Yora; 2021-02-24 at 06:06 AM.
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    Quote Originally Posted by Yora View Post
    The problem with turning most of the atmosphere into biomass is that we first would have to reduce the temperature down from over 400 degrees. Celulose and hydrocarbons ignite at those temperatures, and any kinds of plants to turn CO2 into celulose require liquid water. Not to mention proteins which break down at a measly 40 degrees.

    While there are extremophile microbes on Earth, the extreme temperatures they can survive in are in the range of 80 to 120 degrees. And they still require liquid water.

    Populating Venus with life to make it habitable for life doesn't work.

    I don't know if machines are plausible that use solar power to convert CO2 and local minerals into a compound that is stable up to 500 degrees. But it would be incredibly slow.
    That's why the plan isn't to convert it to biomass, not right away anyways. Adding hydrogen causes a chemical reaction which results in graphite and water. It takes a lot of heat to create this reaction, but Venus is hot enough for the reaction to happen naturally. This will reduce the amount of CO2 in the atmosphere, allowing the planet to begin to cool. The reaction itself should also cool things down, though I'm not 100% positive that it is a endothermic reaction.

    The only thing you need to do for this to work is to throw an entire ice moon at Venus. Preferably Hydrogen around an Iron core.
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    Default Re: Venus or Mars for terraforming and colonisation?

    Part 2, in which I provide arguments for the opposing opinion:

    One issue I was thinking of was that even if you could turn the CO2 into stable solid molecules to fall to the surface until the CO2 levels are down to 415 parts per million, there would barely be any atmosphere left with the measly 3.5% of Nitrogen that Venus has. So I did the math. I couldn't really find out how I get from ppm to Gt to calculate the exact amounts, but even assuming atmospheric gasses weigh about the same, it became immediately obvious that it doesn't matter.

    Even if N2 on Earth is 781 parts per thousand and on Venus only 25 parts per thousand, the fact that Venus has a much more massive atmosphere means that there's about four times as many Nitrogen on Venus than there is on Earth. Even if the weights of the gases are pretty unequal, it still should come out as "a lot more".

    The total amount of noble gases seems to be roughly comparable.

    Sulfur dioxide is 1 ppm on Earth and 150 ppm on Venus. Again, ignoring that gases have different weights, that still comes out as 10,000 times as much of the stuff on Venus as on Earth. SO2 reflects solar energy instead of trapping it. And I believe it is significantly more effective in that regard than CO2. So you probably could get away with much higher concentrations of CO2 than on Earth.
    That is, if you don't mind all the moisture in the air being sulfuric acid. And air pressure would still be something like 4 times higher than on Earth. But hey, it's a start.
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    Default Re: Venus or Mars for terraforming and colonisation?

    Quote Originally Posted by Yora View Post
    Part 2, in which I provide arguments for the opposing opinion:

    One issue I was thinking of was that even if you could turn the CO2 into stable solid molecules to fall to the surface until the CO2 levels are down to 415 parts per million, there would barely be any atmosphere left with the measly 3.5% of Nitrogen that Venus has. So I did the math. I couldn't really find out how I get from ppm to Gt to calculate the exact amounts, but even assuming atmospheric gasses weigh about the same, it became immediately obvious that it doesn't matter.

    Even if N2 on Earth is 781 parts per thousand and on Venus only 25 parts per thousand, the fact that Venus has a much more massive atmosphere means that there's about four times as many Nitrogen on Venus than there is on Earth. Even if the weights of the gases are pretty unequal, it still should come out as "a lot more".

    The total amount of noble gases seems to be roughly comparable.

    Sulfur dioxide is 1 ppm on Earth and 150 ppm on Venus. Again, ignoring that gases have different weights, that still comes out as 10,000 times as much of the stuff on Venus as on Earth. SO2 reflects solar energy instead of trapping it. And I believe it is significantly more effective in that regard than CO2. So you probably could get away with much higher concentrations of CO2 than on Earth.
    That is, if you don't mind all the moisture in the air being sulfuric acid. And air pressure would still be something like 4 times higher than on Earth. But hey, it's a start.
    It does get complicated and messy after step 1. I mean, the water you are creating via the reaction in question becomes water vapor, which is a more powerful greenhouse gas than CO2. But it's also a lot more reflective than CO2, so it can also lower the heat coming in. But also also, the water vapor does contribute to the weight of the atmosphere. But it is actually lighter than CO2, so it would still go down. And thankfully that would help dilute the sulfuric acid, though I'm not sure by how much.

    But yeah, it's a start. There are likely a bunch of other steps needed to actually get Venus to living condition. Still, I do think it's easier than Mars. Because I just don't think it's easier to add that much atmosphere to Mars. I mean, you might be able to set up a colony on Mars pretty easily, particularly if you did deep into the mantle.

    The core of Mars is a lot colder than ours right? So you could dig much deeper than you can on Earth which would help with dealing with gravity, duststorms, and space debris.
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  30. - Top - End - #90
    Dwarf in the Playground
     
    Imp

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    Jan 2019

    Default Re: Venus or Mars for terraforming and colonisation?

    You don't need to convert the CO2 to oxygen and carbon, and you actually don't really want to. What you want to do is cool the crust enough that the rock can weather. The reason there is so much CO2 is that rocks that would be carbonate at reasonable temperatures break into carbon dioxide and oxide rocks at higher temperatures. Even if you were able to split all the carbon dioxide you would still be left with ~70 bar atmosphere of pure oxygen, which isn't much better (and good luck managing any coal fires that break out). To call it terraformed you need to react the carbon dioxide with rock instead, which requires you to cool the whole planet crust down first. The same process gets rid of the SO2.

    Doing this is hard. Even with no sunlight at all the surface would stay hot for an absurd length of time so a sun shade of some form would be the easy part. Getting the atmosphere to stop behaving like a blanket is not easy. There might be a way though. The first step would be to seed the clouds to cause much larger droplet size than normal in the sulphuric acid clouds. You might even have to artificially capture large quantities of sulphuric acid and drop it through a pipe, so droplet size is in the cm range. The goal is to cause a massive storm in a single location, using the sulphuric acid as both a pump and heat exchanger. The deeper down you can deliver the sulphuric acid the more powerful the convection you drive, hence wanting large droplet size. Once you can start to get some sulphuric acid all the way down to the ground it will start to react with rock to form sulphates, slowly pulling the SO2 out of the atmosphere. You don't need to cool down the whole crust to do this. Ideally you want to localise rainfall over a single area that you cool down first as a sink for sulphur. If you can get rid of the sulphur dioxide the greenhouse effect is not nearly so extreme, and you can then continue the storm cooling with water. If you choose your location right to start with you might be able to keep the majority of the water on the planet in the same area constantly powering your storm. That means that water vapour will not be a significant greenhouse gas everywhere, but would still drive a powerful convective heat transfer.

    Hitting it with a couple of large icy comets might be an idea, because the more liquid phase components to the atmosphere the faster it can cool down, and I can't find one of those that doesn't need hydrogen. 10 comets the size of Haley's comet would ~double the amount of hydrogen available, so those are viable numbers. Regular bombardment with comets throwing dust into the upper atmosphere could even be how you shade from the sun. The life of a terraformer would be interesting, to say the least. You would be constantly living in the heart of a storm on a planet that people are deliberately throwing things at!

    Even if you do manage to get the surface cool, the timescales and amount of work to get all the carbon dioxide to weather is extreme. You would need to turn the entire surface into gravel to a depth in the tens to hundreds of meters if you want it to go at any pace. Fracking type techniques might work, but cooling subsurface rock is much harder too.

    If you do all that, you should be left with a liveable planet. It should even be stable, because I think it is the hydrogen that caused the runaway in the first place. As long as you can get it cool enough that carbon and sulphur stay in rocks you should be fine.

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