April 07, 2008
Venus, Evolved

New discoveries continue to come from the Venus Express space probe, each one more fascinating than the next:

In the early stages of the Solar System, Venus seems to have evolved very rapidly compared to the Earth. Data from Venus Express supports the theory that the Earths twin once had significant volume of water covering the surface but it appears that these oceans were lost in a very short geological timescale.

While it's pretty obvious it will be a very long time indeed before anyone sets foot on the Venusian surface, I sometimes wonder how difficult life would be in the very high upper clouds. There are almost certainly areas in the atmosphere with Earth-like temperatures and pressures. If they're clear of Venus's famously acidic lower atmosphere, it would seem an interesting place to set up a "floater's camp."

Posted by scott at April 07, 2008 11:34 AM

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Me, I just think that Venus didn't have enough time to evolve an Al Gore before its greenhouse effect happened... ;-)

Posted by: Mark on April 7, 2008 01:09 PM

I actually looked up Pioneer space probe information on the NASA website, out of curiousity. Unfortunately, the sulfuric acid clouds extend just a bit too high; at the point where they top out, the atmosphere of Venus is only 1/10th the density of Earth's, and the average temperature is -30C (-22F). Human survival without pressure suits requires an atmospheric pressure of at least 3/10ths Earth's, and the combination of pressure and temperature ensures that no earthly material capable of enclosing a hydrogen-filled space would be able to float in the atmosphere at that height, even after taking the greater molecular mass of Venus's atmosphere into account; the mass of the material used to enclose such a space would be greater than the balloon's displacement, even as a perfect sphere.

The best that could be hoped for is a balloon about 10 km below the tops of the clouds, carefully treated to resist the intrusion of sulfuric acid, or by steering clear of the cloud tops (good luck with that). The temperature would be warm, but tolerable (80F), and the pressure (about half the Earth's surface pressure) would make it navigable by hydrogen zeppelin. Of course, an "OH THE HUMANITY" moment would inevitably be fatal for all aboard, making such a venture more risky than any non-authoritarian government would accept.

Posted by: Tatterdemalian on April 7, 2008 01:42 PM

Cool! I've wondered about this for quite some time, nice to know the basic answer.

If nothing else, it seems to me it'd make the start of an interesting SF short story.

Posted by: scott on April 7, 2008 02:03 PM

Indeed. If it wasn't for lack of water, Venus would be not only colonizable, but actually productive. Earth has many plants with waxy coatings that would resist the slight concentrations of sulfuric acid present in the habitable layer, and they would have a field day generating polymers and sugars from the CO2 and sunlight in the Venusian atmosphere. Hydrogen could be extracted from the sulfuric acid with reusable palladium catalysts, and with equipment and people to weave new balloons from the plant material, such a colony could stay in the air for quite a long time.

Sadly, it would take far more water than could be extracted even from the sulfuric acid in the atmosphere. Then again, Al Gore says the seas are going to flood Earth any day now (though strangely it seems to be arriving in the form of snow in the UK), so maybe shipping it to Venus will solve that problem.

Posted by: Tatterdemalian on April 7, 2008 02:16 PM

Indeed. If it wasn't for lack of water, Venus would be not only colonizable, but actually productive. Earth has many plants with waxy coatings that would resist the slight concentrations of sulfuric acid present in the habitable layer, and they would have a field day generating polymers and sugars from the CO2 and sunlight in the Venusian atmosphere. Hydrogen could be extracted from the sulfuric acid with reusable palladium catalysts, and with equipment and people to weave new balloons from the plant material, such a colony could stay in the air for quite a long time.

Sadly, it would take far more water than could be extracted even from the sulfuric acid in the atmosphere. Then again, Al Gore says the seas are going to flood Earth any day now (though strangely it seems to be arriving in the form of snow in the UK), so maybe shipping it to Venus will solve that problem.

Posted by: Tatterdemalian on April 7, 2008 02:17 PM

As best as I remember, blue-green algae feeds on sulphuric acid--so we could theoretically start terraforming Venus by shooting algae into the atmosphere.

Posted by: Bigwig on April 8, 2008 09:20 AM

I can think of a least a few kinds of life which subsist on some sort of sulfide, but I can't think of any that can do without water. I'm not enough of a chemist to know if there is SOME sort of chemical reaction that starts with CO2 and whatever the hell the notation for sulphuric acid is and ends up with water and oxygen and a net gain in energy. Something tells me it'd involve some big, heavy, expensive chemical plant. Especially if NASA got involved.

Still, it'd make for a fun short story. Jonny AlgaeSeed floating over the cloud tops of Venus, sort of thing.

Posted by: scott on April 8, 2008 10:15 AM
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