Venus May Have Been Habitable, Says NASA (sciencedaily.com)

EzInKy writes: Science Daily has an article speculating that Venus may have been habitable which is suggested by NASA climate modeling, which proposes that Venus may have had a shallow liquid-water ocean and habitable surface temperatures for up to two billion years of its early history. Talk about global climate change run amok. Venus may represent a near Earth example of what is in store for the future of our world if we don't make it a number one priority to address. Science Daily reports: "Venus today is a hellish world. It has a crushing carbon dioxide atmosphere 90 times as thick as Earth's. There is almost no water vapor. Temperatures reach 864 degrees Fahrenheit (462 degrees Celsius) at its surface. Scientists have long theorized that Venus formed out of ingredients similar to Earth's, but followed a different evolutionary path. Measurements by NASA's Pioneer mission to Venus in the 1980s first suggested Venus originally may have had an ocean. However, Venus is closer to the sun than Earth and receives far more sunlight. As a result, the planet's early ocean evaporated, water-vapor molecules were broken apart by ultraviolet radiation, and hydrogen escaped to space. With no water left on the surface, carbon dioxide built up in the atmosphere, leading to a so-called runaway greenhouse effect that created present conditions."

Comments

Venus should be habitable higher up

[the_humeister]

in the clouds where it's more Earth-like.

Re:Venus should be habitable higher up

[stealth_finger]

Tonight the weather in cloud city is cloudy, followed by clouds,

Re:Venus should be habitable higher up

[Rei]

No, that's not "about it". The things that are earthlike include:

* Temperature
* Pressure
* Gravity
* Radiation shielding (compared to other destinations)
* Sunlight levels
* Atmospheric turbulence

The environment is amazingly earthlike, except for the chemistry. And concerning the chemistry....

The air is still unbreathable and full of sulphuric acid.

The phrase "full of sulfuric acid" gives completely the wrong impression. The sulfuric acid mists in the cloud deck at reasonable heights (~54km., give or take a couple km) are on the order of half a dozen ppm. They're not much higher than the OSHA standards for breathing sulfuric acid mists during an 8 hour shift. Now, Venus's H2SO4 mists are a higher concentration than those on Earth, and there are also anhydrous acidic components. But comparisons to a bath in sulfuric acid are totally inappropriate. It's more like a bad smog or vog (in fact, it is a bad vog).

Oh, and sulphuric acid isn't very friendly to most building materials either.

When you're talking about plastics (were you actually thinking that one would make a blimp's skin out of steel?), sulfuric acid is well tolerated by a large number, if not the majority of plastics. Organic solvents are much more concerning - I'd have much greater concerns for a blimp on Titan. Some fluoropolymers, like FEP and PTFE, are so chemical resistant that they're easier much defined by what does hurt them than what doesn't.

Realistic flight envelopes are not a single component. You generally will have an outer anti-corrosion layer (generally a fluoropolymer... the least fluorinated that provides the desired properties; ECTFE or PCTFE would be excellent), with one or more layers for permeation resistance and strength (generally biaxially-oriented when strength is of concern, like BoPET); for extra permeation resistance, something like EVOH or PVDC), optionally an inner layer (condensation control, anti-fouling, melt-through lamination, etc), optionally adhesive layers (such as EVA-based), and fiber reinforcement (vectran is popular for Venus proposals, although would be somewhat difficult for local production; on the opposite end of the spectrum, the easiest possibility for local production would be UHMWPE, but you'd need to ensure proper UV resistance and that the film components are compatible with the inevitable creep... though to be fair vectran also needs UV control) (there are countless fibers in-between with varying tensile, UV, chemical, creep, etc properties).

Beyond the basic skin you also need ballonets; most likely an additional phase-change envelope for altitude stability; catenary curtains and cables to distribute the weight to hanging structures; and in some cases, where objects need to be kept a minimum distance away from the envelope (such as propulsion), collapsible trusses. You also need mist collection for local propellant production (there are many different architectures, but they're all built around the fact that all of Venus's mists are highly hydrophilic and thus readily condense into water (through membranes or exposed) and onto hydrophilic surfaces. Lastly, if you use a ballute approach (for any combination of reentry, atmospheric deceleration, and/or initial inflation), you need a burble fence (which could potentially double as mist collection, depending on the architecture).

In cases where you might have exposed metal - such as propulsion motors (although even that isn't an inherent requirement) - there are a lot of alloys considered to be fine in Venus-conditions, and indeed which have been used on Venus probes in the past. An example includes Hastelloy C22. You may have noticed that here on Earth, metals in industry are frequently exposed to extremely corrosive chemical production environments for very long times. You design to your environment. A more

Re:Venus should be habitable higher up

[Rei]

Actually, both water and oxygen are surprisingly simple... thanks to that sulfuric acid that often is used against the concept of Venus as a destination. Simple heating of sulfuric acid first yields any dissolved water (Venus's H2SO4 is 75-85% concentration). Further heating decomposes H2SO4 into H2O and SO3. Further heating still in the presence of a catalyst decomposition SO3 into O2 and SO2. As far as industrial processes go, it's on the "easy" end.

One issue is that D/H ratio. Over 1% of the hydrogen is deuterium. While it's known that people can survive at high deuterium levels, there is some controversy over whether prolongued exposure may cause other health effects; for example, one study suggests increase incidence of depression at levels far below that encountered on Venus. Unlike most isotopic differences, deuterium has significantly different properties than light hydrogen. Deuterated drugs, for example, can have lifespans in the body many times higher than their non-deuterated equivalents. Deuterated plastics are often far more transparent than non-deuterated ones. Contrariwise, mixtures of deuterated and non-deuterated plastics are often highly opaque because deuterium changes the melting point enough for the plastic to fractionalize into an anisotropic mixture of varying densities (and thus refractive indices).

On the other hand, at a value of nearly $1k per kilogram, deuterium is a potential export product, if one can get launch costs down enough. And there's a rather clever way to do isotopic separation on Venus. You have to store power; this is a given, until one advances to the point of being able to make use of wind differentials at different altitudes. Rather than batteries, you can get a better mass ratio from fuel cells (hydrogen-chlorine fuel cells being a better option than hydrogen-oxygen due to the reduced overpotential requirements at the chlorine end and generally more favorable reaction dynamics). Also, unlike most H2-O2 PEMs, H2-Cl2 fuel cells tend to be readily reversible. The key is that, by far, the best technique for isotopic enrichment (in terms of enrichment factors) is electrolysis. It's not widely used on Earth because of how much energy it takes. But if you need to perform electrolysis either way to store electricity, it's no extra cost. You can also gain an enrichment factor on the recombination side as well. The only cost you have to pay for enrichment in this manner is the wiring of your fuel cell stack in a cascade, as well as extra tankage other plumbing mass for each of the intermediary stages (I could dig up my calculations at one point, I've already worked out how many stages you'd need and how many fuel cell layers would need to go to each stage in order to achieve a given voltage and given isotopic concentration at each end). If I remember right, you get about 17% of the hydrogen mass in the fuel cell system out on the de-enriched end every day.

And Russians landed on that thing, 10 times

[melted]

And transmitted images digitally from the surface, in 1975. Cold War was a gift to mankind, that pissing match was legendary.

Re: And Russians landed on that thing, 10 times

[Anonymous Coward]

Yes, it was about ideas, not about profit. Anyhow the MBAs and Wall Street speculants won the Cold War. After USSR dissolved billions upon billions were stollen from the ex-USSR in goods and sold to others. And don't get it wrong. If it was USA to go down, the same MBAs and Wall Street scumbags would have done the same. Thing is... There is no one left who can pay.

Re:Two more problems with Venus

[NotAPK]

I'm sorry but Venus is not tidally locked to the Earth. Or the sun. More info. The orbit is "normal" (it has to be or it would fall into the sun, or leave the solar system) but the rotation is both very slow, and in the opposite direction to all the other planets in the solar system.

Awful summary

[Anonymous Coward]

The summary sucks for plenty of reasons. The original NASA article isn't loaded up with alarmist bullshit. Earth will eventually become as hot as Venus and there will be a runaway greenhouse effect. However, that's extremely unlikely to be due to human activities. The Earth has been significantly warmer in prehistoric times and didn't undergo a runaway greenhouse effect. Carbon dioxide levels have been much higher, but it didn't cause the oceans to evaporate away, either. Humans are likely to eradicate themselves from the planet long before they can make that occur. It will happen as the sun becomes brighter and expands, which will eventually cause the Earth to heat irreversibly and evaporate the oceans. It damages the credibility of climate scientists to attribute ridiculous claims to them, especially when they said nothing of the sort.

Now, any study like this depends on the validity of the model and the assumptions made in its configuration. The manuscript was recently accepted to JGR, but hasn't yet gone through a copy editor. I'm not about to pay Wiley for an article that's still in preparation. Unfortunately, I can't comment on the validity of the model without reading the paper. That's said, the abstract says nothing about human activities causing this on Earth. Please leave alarmist bullshit out of stories. The submitter and the editor who posted it should be ashamed.

Re:Cannot happen in earth, period.

[AC-x]

On the other hand climate change likely had a large part in the biggest mass extinction's in earth's history. Do you really think we should be playing Russian Roulette with the Earth's climate? Not to mention a) causing millions of deaths from pollution every year, b) funnelling money in to unstable middle eastern regimes and c) using up a resource at an increasing rate that we know is finite and will run out in the future.

Re:Two more problems with Venus

[packrat0x]

Venus is *ALMOST* tidally locked with the sun. Its rotation is slightly retrograde. The problem remains: It needs to rotate faster to even out solar heating.

So much bad information

[sjbe]

Wow you crammed a ton of incorrect information into a single post. Are you trolling or just too stupid to look things up?

On Earth it appears that the oceans put enough water into the crust as to make plate tectonics possible (the water lubricates fault lines. If Venus ever had plate tectonics, it probably stopped when the water evaporated.

Water is not and never has been a requirement for a planet to have plate tectonics.

And then there is the fact that Venus is tide-locked between the Sun and Earth (always has the save face toward Earth when the two planets are closest together)

Not only is Venus not tide-locked to earth, it doesn't even rotate in the same direction as earth. Venus has retrograde rotation (rotates clockwise when viewed from north pole) and it has the slowest rotation of any planet at 243 earth days for one rotation. It would be impossible for a plant to be tidal locked to another planet. Tidal locking happens in objects that orbit each other. Venus obviously does not orbit Earth.

Earth's magnetic field exists partly because of its rotation, and that magnetic field helps protect its atmosphere. Venus hasn't got the necessary rotation rate.

Earth has a dynamo in it's core whereas Venus does not. Simulations have shown that Venus' rotation is adequate to produce a dynamo but Venus doesn't have one because it has insufficient convection in the core. Venus does have a (comparatively) small induced magnetic field but it is too small to provide meaningful protection from solar wind.

I once speculated about a way to make Venus habitable.

Since you clearly have no idea what you are talking about I suggest you cease doing that until you learn considerably more than you are demonstrating.