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B Venus, terraforming

  1. Aug 24, 2015 #1
    Dear PF Forum,
    Why nobody ever thinks of terraforming Venus? Many propose Mars, even as far as Europa (not the continent!) or Titan. Mars has very little atmosphere compared to Earth. Titan has thick atmosphere but too cold.
    I once read that Carl Sagan proposed the idea by spreading bacterias in upper atmosphere, where the temperature and the pressure are not so high.
    If I'm not mistaken the equation of photosynthesis is:
    6CO2 + 6H2O + Sun light -> C6H12O6 + 6O2
    This process will surely eliminate greenhouse gas(CO2) The only problem is that it needs water/hydrogen.
    But most of the material are there. Sun, CO2.
    And once the atmosphere is diminished then there's no abundant greenhouse gas, the planet temperature will drop. And the planet are left with many glucose residue on the "soil". Which is suitable for at least insect and other simple organism. After that we can introduce simple plants, algae, moss?
    All this only involved biology tools, not mechanical tools to convert Venus.
    Considering that Venus mass is almost like Earth mass and its gravitational pull close to Earth's, it's a suitable planet for habitation.
    Is this terraforming idea possible?
    Why nobody ever discuss it? Does the lack of hydrogen/water in the photosynthesis process makes it difficult?
  2. jcsd
  3. Aug 24, 2015 #2


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    Well, that's one of the things that makes it difficult. Finding bacteria that could live in the conditions are another. Lots of chemicals that are unwanted is another, since there is rather a lot of sulphur. Plus, the atmosphere is something like 50 times as dense as Earth's. So there would be something like 600 pounds per square inch of material that would have to precipitate out to get the atmosphere close to Earth's. Since little of it is water, that is an interesting surface you have produced. Sulphurous candy floss many meters deep it seems like, even supposing you could get enough H and O.

    As an exercise: Suppose you had an atmosphere on Venus similar to the Earth's. What would be the average surface temperature?
  4. Aug 24, 2015 #3
    You mean 80% Nitrogen, 20% Oxygen and 1% other? And 1 bar atmospheric pressure, (earth bar).
    The average surface temperature? Frankly I don't know. :smile:.
    Axial tilt is 2.640, compared to earth 230. I suspect the wind is slightly mild, less hurricane than earth. If the pressure is 1 bar. Summer/Winter is similar. That will heat the planet more than earth. In winter, most of earth surface are covered by ice, so it reflects sun light. If summer/winter in Venus is similar, then Venus winter doesn't create too much ice, except in the pole.

    Venus distance as I read in Wiki is 104/107 millions KM. Compared to Earth 150 millions km. Further reading it's just slightly beyond habitable zone. Some estimates it's in the range of 0.725 AU to 1.24 AU. And frankly I have no idea if the earth is moved to Venus orbit, what will its surface temperature, much less Venus. Can you give me a rough estimate. Just for curiosity sake.
    [Add: Move earth to Venus orbit, but preserving axial tilt, rotation period (sidereal day must be adjusted, because now Earth will orbit the sun at 224 days, if my math is correct its sidereal day, supposed rotation is 24 hour, is: 23 hours 53 minutes]

    Btw you say, "Finding bacteria that could live in the conditions are another", you imply that finding bacteria that could live on Venus atmosphere is probable or even simply possible? I mean in the upper atmosphere where the pressure/temperature are not so high. Many CO2, there. But I'm afraid there are only CO2, non sulphur or hydrogen, nitrogen. Vital for carbon base life like earth.
    Last edited: Aug 24, 2015
  5. Aug 24, 2015 #4
    The Venera landers sent by the Soviets lasted less than an hour before breaking down due to extreme conditions at the surface.
    Air pressure is equivalent to about 1km deep in the Earth's oceans, temperature is hotter than the maximum of a domestic oven, it will melt some metals, lIquid H20 is impossible. (It's not significantly cooler at the poles due to circulation and a very thick blanket of cloud), in addition to which it rains sulphuric acid.

    Converting that to something which could be survived by Earthlike life forms would at least require removing most of it's atmosphere.
    In it's present form Venus is a place which guarantees rapid sterilisation and the extinction of any Earthlike life.
  6. Aug 24, 2015 #5
  7. Aug 24, 2015 #6
    So I read. There are many probes even robots in Mars (Sojourner, Spirit, now Curiousity 2012), but less for Venus. At least less popular than Mars Rover.
    Some movies show life on mars:
    - Red Planet
    - Capricorn One
    - Total Recall 1991
    - The Martian,
    Interest in Mars is greater than Venus.
    Yes, air circulation and convection is much faster than water/ocean.
    Good sign. There are hydrogen and sulphur, building block element for carbon based life.
    I mean by "removing" is to convert CO2 to something like glucose C6H12O6 by bacteria, not removing CO2 to outer space
    Of course.
  8. Aug 24, 2015 #7
    1961 eh. I read Carl's book in 1980s he mentioned terraforming in 1 chapter, not the whole book. Still got the book at the attic.
    Highly technical problem, Sagan's idea is much simpler.
    That, I didn't read in my book. That's why people abandon this idea?
    That's the biggest obstacle of all. Lower latitude will be impossible for 121.5 days light. I imagine colonization in higher latitude with its axial tilt 2.640, perhaps somewhere at 750, like 17:00pm or 07:00 am. It will be suitable for 121.5 days light. But it will be very cold at 121.5 nights. Even though it can cause tremendous hurricane and as it is written, "which could prove difficult for most known Earth species of plants and animals to adapt to."
    I should have read that Venus rotation is 243 earth days.
    Another link from wiki: https://en.wikipedia.org/wiki/Colonization_of_Venus
    Are they serious?
  9. Aug 24, 2015 #8


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    The atmosphere of the infant earth was probably quite similar to the atmosphere of Venus. Lava outgassing was primarily responsible for the atmosphere of the infant earth. And that mix of gases would not be conducive to life. The major difference is early earth had far greater amounts of water vapor in its atmosphere - probably delivered during the heavy bombardment period. Perhaps earth intercepted far more icy bodies that delivered primordial water than did Venus. Perhaps earth possessed far greater indigenous water reserves than Venus. Either way, water influenced the evolution of earth's atmosphere in dramatic ways. Just seeding microorganisms into the Venusian atmosphere would probably be hugely ineffective. Injecting vast amounts of water appears to be a better terraforming strategy. See here; http://www.globalchange.umich.edu/g...lectures/Perry_Samson_lectures/evolution_atm/, for discussion.
  10. Aug 24, 2015 #9
    Good link. Thanks. I wonder why Venus haven't experienced "Heavy Bombardment Period" It's 4.5 billions years ago, right? Water from comets. And as I read the ratio of water is "just right" so Earth can have ocean 70% of its surface, or we wouldn't be discussing it.
  11. Aug 24, 2015 #10


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    The most likely explanation is Venus was unable to develop and retain sufficient water reserves. Perhaps due to its proximity to the sun, lower gravity, slow rotation, or combined effects of other factors.
  12. Aug 24, 2015 #11
    Another idea are metal coated balloons floating in the upper layer of the atmosphere, reflecting sunlight and emitting thermal radiation.

    Yes, bacteria simply doesn't work without hydrogen. And with hydrogen they wouldn't be required. That's explained in the following paragraph.

    Yes, this is a possibility.
  13. Aug 25, 2015 #12
    Also I would like to point put the sheer fact that Venus is closer to the Sun than Earth. Even if we could terraform Venus so that it was habitable, this would not be an ideal location in the long run as scientists are trying to colonize other planets to escape this growing star. This is why planets further away from the Sun such as Mars offer a more viable solution to our problems. Also Mars actually has the ability to contain water (as seen by the ice) and other vital elements to human life.
  14. Aug 25, 2015 #13
    Come on. How long do you suppose it will be. In the next 2 billions years the sun will become red giant. I'll bet in the next 1000 years, with advanced 1000 years technology, human can terraform, at least, every planet on solar system. I see an episode in star trek (300 years from now), there's is a character whose job is terraforming.
    Yeah, if we can build a nuclear reactor such as in Total Recall. But Mars' atmosphere is very thin compared to Venus. At least there's something to start.
    Last edited: Aug 25, 2015
  15. Apr 20, 2016 #14
    Would a nuclear winter cool the planet, and by how much??
  16. Apr 20, 2016 #15
    That's not what I had in my mind. You can't live there, either.
  17. Apr 20, 2016 #16

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    This is not very good evidence of anything.
  18. Apr 20, 2016 #17
    I can imagine some sort of engineered bacteria that could float in the upper atmosphere, where the temperature isn't so extreme. With genetic engineering I suppose even in Mercury we could put modified forms of life.
  19. Apr 20, 2016 #18
    Sure, Star trek is not evidence of anything.
    Mercury is too close to the sun, and it does not have atmosphere.
  20. Apr 20, 2016 #19
    If you check out Martin Beech's extensive work, you'll see that terraforming Venus would be 'hard, but do-able'. Blowing off even a significant fraction of that appallingly noxious atmosphere by direct or grazing mega-impacts would need far too many icy objects to be worth-while. IIRC, Beech's 'papers' in 'Journal of British InterPlanetary Society {JBIS}, dating back to ~ 1991, covered many other options, including progressively building a balloon-lofted lid over Venus and living on that...
  21. Apr 20, 2016 #20


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    Venus has a problem similar to mars, making it a poor candidate for terraforming - it lacks an intrinsic magnetosphere. Assuming you could reduce atmospheric density to a level compatible with earth life forms; the sun would begin stripping away its now thinner atmosphere with a vengeance - much faster than the depletion suffered by mars. The thick atmosphere of Venus generates an induced magnetosphere which protects it from the solar wind. There is no free lunch on Venus.
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