Venus

RobertDyck · 2013-04-19 02:58:01

JoshNH4H,

I appreciate you posting here instead of in the discussion thread about crops for a Mars settlement. NewMars does have an issue of getting off-topic. Often.

First, I proposed sequestering CO2 from the atmosphere of Venus as polyanhydride. You claim this material has never been made. It has. Wikipedia has an article about it here. It's usually been made as a co-polymer with other materials, where those other materials are deliberately designed to degrade easily and quickly. However, the same article also states that as a pure material, polyanhydride is much more durable and a much stronger and harder polymer. Since the material tends to "unravel" once broken, I proposed to place a strong end-group on each end of the polymer chain. I came up with a few candidates, but in the end chose to leave it up to chemists. The issue is what is available in the atmosphere of Venus, and what can we afford to expend. For example, if we use nitrogen then will Venus have enough nitrogen to support a biosphere? The atmosphere of Venus currently has 6 times partial pressure of nitrogen as Earth, but once you create a full planetary biosphere, much of that nitrogen will be consumed by plants.

Will polyanhydride survive current conditions on Venus? It will survive current conditions on Earth. Enough research has already been done to make that determination. As for Venus, there just isn't enough research. Especially not any research with strong end-groups. Rather than dismiss the idea, just do it. We can certainly simulate Venus atmosphere conditions here on Earth. So instead of summarily dismissing ideas, just do the research. If you're either not willing or not able to do the research, then don't dismiss someone else's ideas.

One key criteria of my ideas is that terraforming an entire planet cannot be done by transporting materials from another planet. Resources necessary to move enough material from any planet to another are extreme. You can afford to transport seed material, including single cell organisms or plant seeds, but not bulk materials. Do not try to remove the atmosphere of Venus to space, or Mercury, or anywhere else. Do not try to import bulk materials. Instead work with what's there.

As for genetic engineering: if you claim the only thing that can be done is what has already been done, then the airplane would never have been invented. Nor the automobile. We certainly would never have made it into space. We would still be riding horses. Nature already has organisms that spend their entire life cycle, including reproduction, in the air, so genetic engineering an organism to do the same is no more than splicing. That includes "flaps" to ride air currents, and a "taxis" (single cell equivalent to instinct) to seek appropriate temperature, moisture, and nutrients. As I mentioned many times, there is already retinal, a photodye that is composed exclusively of carbon hydrogen oxygen and nitrogen (CHON). It's purple instead of green, but halobacteria already use it. So splice those genes. Chlorophyll requires one atom of magnesium per molecule, and it's green. There isn't any magnesium in the clouds of Venus. Again, this means using what's available in the clouds. Cell membranes are composed of lipids, made entirely of carbon hydrogen oxygen and nitrogen. Amino acids are composed of those same 4 elements. DNA is composed of those 4 elements plus phosphate. There are sulphur loving extremophiles on Earth, and plenty of sulphur in the clouds of Venus. So yes, I am arguing for engineering an organism that uses these 6 elements: C, H, O, N, S, P. If you want to include anything else, then ensure it's available in the clouds of Venus. Yes, producing polyanhydride will require much more genetic engineering than just splicing a gene from another organism, but that's engineering. Don't bitch, just do it.

As for where I live: Yes I live in Canada. I did live in a suburb of Richmond, Virginia, in 1997. That's before founding of the Mars Society. And Miami Florida in 1999/2000. I did come down to DC in 2005 for a NASA conference. I'm rather disappointed that I didn't get the NASA contract I was bidding for. Unfortunately an employee of Lockheed-Martin was in the audience. After my presentation to NASA, Lockheed-Martin bought the American subsidiary of one of the two suppliers I was counting on, then landed the NASA contract to do exactly what I proposed. Lockheed-Martin has taken many of my ideas. What are you going to do when they buy the entire company? I didn't make it for the Mars Society conference in DC. I was a regular conference attendee while my finances could afford it. I have difficulty justifying such trips when there isn't any work involved.

Last edited by RobertDyck (2013-04-19 05:13:59)

Terraformer · 2013-04-19 04:07:07

Josh,

The great thing about sending metals, especially aluminum, from Mercury is that you can make sunlight do all the work. Launch them as folded up solar sails using a mass drive, and let the sun push them to Venus. Sure, it takes energy to do that, but Mercury has lots of that.

Personally though, I'd rather get actual water clouds first, and then maybe cool the planet down with an atmosphere based sun shield to the point where we can operate on the surface much easier and hopefully cause it to weather with the ground to form carbonates. If it's cold enough for oceans to form (which still means temperatures are in the hundreds of degrees Celsius), then the oceans are likely to be very acidic from dissolved CO2 - hopefully this will help them react with the crust. We might have to fracture the crust a lot more to allow for it to work better, but carbonated water should carry the CO2 down a long way. Maybe if we're lucky, we could get it down to the sort of world Carl Sagan thought was there...

StarDreamer · 2013-04-19 07:26:30

Robert;

That's too bad about NASA and Lockheed, but it sounds so typical. Nice guys finish last. Too bad the world is like that, but twas ever thus.

I've been to Winnipeg and as far north as Gimli and Hecla. Amazing that grapes will grow there!

I am hearing that Venus lacks phosphates, which are essential for DNA. So that's one thing your plan would need to import. I dont know if RNA would give us a leg up on that problem or not. One way of looking at the challenge is to say: the seeds of life are everywhere, but successful life is not. I am sure we will find evidence of early life on Mars, for ex, but it got only so far there and then failed (barring the discovery of extremophiles in the water layer of the Martian crust). Ditto for Mercury and Venus, Ceres and Europa and every other little world in our solar system. In the cold worlds, the seeds shall be there still, dormant, resting, awaiting a day of warmth and light to awaken them and give Life a try. So the challenge on Venus is to turn back the clock of life on Earth to the place where what we got here could survive there, figure out where evolution took the wrong turn, then give it a push in a new direction. So, yes, if you cant do chlorophyll or haemoglobin (which are similar at the molecular level -- blood uses iron instead of magnesium), then do retinal. But is there a substitute for phosphates in DNA? Can we even imagine one? What might work? The alternative is to source phosphate and import it to Venus, then hope Life can recycle that supply into future generations. I dont know if that's practical. Or we maintain a station in the clouds of Venus to breed our little organisms and release them generation after generation.

RobertDyck · 2013-04-19 18:11:21

There is phosphorus in rocks on Venus. And it hasn't been confirmed, but I believe the same process that causes CO2 to combine with sulphur in rocks to form carbonyl sulphide (COS), also works with phosphorus. There is such a thing as carboxyl phosphate, but COS is a metal carbonyl. If that forms with phosphorus, it would be P(CO)3. But when carbonyl sulphide breaks down at middle altitudes, it forms CO2 and SO2. That SO2 then continues to rise into clouds. But a metal carbonyl of phosphorus would breaks down to phosphate, or carboxyl phosphate, or possibly carbamoyl phosphate. The latter two would break down in Venus atmosphere. Break down into whatever form would precipitate out of the atmosphere. The question is how do we get phosphate to rise into the clouds? That may require some interesting chemsitry. And would definately require confirmation that phosphorus gas(s) exist in the lower atmosphere.

Void · 2013-04-20 13:43:06

I have no direct answer on Phosphates, except to ask why none would be there in the rocks, as you have said there would be.

You did mention chemistry, so perhaps what I will add will suggest something to you that has not occurred to me.

I am interested Sulfur, Sulfuric Acid, Iron Pyrites, and how they might interplay with the present day presumed stable state of Venus.

Pyrite:
http://en.wikipedia.org/wiki/Pyrite
Solar power using pyrite:
http://techportal.eere.energy.gov/techn … techID=749

Benefits
Pyrite matches well with the solar spectrum, and has a very high absorption coefficient, making it an ideal candidate for photovoltaics. Furthermore, it is more economical than the silicon that is currently used. Once completed, the technology has the potential to provide a cheaper and more efficient alternative to silicon for use in photovoltaics.

The Planet Venus:
http://en.wikipedia.org/wiki/Venus

The atmospheric pressure at the planet's surface is 92 times that of Earth's. With a mean surface temperature of 735 K (462 °C; 863 °F),

Suspiciously close to the decomposition temperature of Iron Pyrites.

Above the dense CO2 layer are thick clouds consisting mainly of sulfur dioxide and sulfuric acid droplets.[49][50] These clouds reflect and scatter about 90% of the sunlight that falls on them back into space, and prevent visual observation of the Venusian surface.

I have seen it stated in another article that solar cells aimed at the planet itself would pick up very significant solar energy.
The point being that an orbital habitat could absorb light not only from the sun but from reflection from Venus through much or the orbit of the habitat. That might be a cost saving as you might get by with a container lined with solar panels, and no aggressive need to point at the sun.

The surface of Venus is effectively isothermal; it retains a constant temperature not only between day and night but between the equator and the poles.[2][53] The planet's minute axial tilt (less than three degrees, compared with 23 degrees for Earth), also minimizes seasonal temperature variation.[54] The only appreciable variation in temperature occurs with altitude. In 1995, the Magellan probe imaged a highly reflective substance at the tops of the highest mountain peaks that bore a strong resemblance to terrestrial snow. This substance arguably formed from a similar process to snow, albeit at a far higher temperature. Too volatile to condense on the surface, it rose in gas form to cooler higher elevations, where it then fell as precipitation. The identity of this substance is not known with certainty, but speculation has ranged from elemental tellurium to lead sulfide (galena).[55]

If this is a sulfate condensate on the tops of the mountains, it is not only interesting, but it suggests that some terraforming notions such as adding Hydrogen to Venus from external sources would lead to more Sulfuric Acid in the clouds.

Here is one more reference with graphs:
http://www.esa.int/Our_Activities/Space … atmosphere

Just a pause for a moment of slight rage. Often when I work on this site, I will compose a significant volume of keyboarding, and all the sudden something will happen, and it will disappear, after I seem to be routed to an unsolicited action. I have learned to save repeatedly.

I believe that the best action for Venus in the beginning is orbital habitation, with devices that use hybrid propulsion. Sulfuric Acid as a substitute for Oxygen, and fuels derived from metals from small asteroids captured, or our Moon, or Mercury.

A device to dive down, and collect Sulfuric Acid, and to also keep it propulsed as it gathers. Having a full tank, rocketing back to orbit with a cargo of Sulfuric Acid. It is my understanding that Sulfur is a good metal in a vacuum. A centrifuge action to collect the Sulfuric Acid is inside of this plan.

I have many ideas beyond that such as collecting all the Sulfur to Orbit, keeping a H2O atmosphere (More Sulfur would likely collect from Volcanos).

But for a start, there is an economy for Venus, mining Sulfuric Acid. Floating Habitats? I suppose a few at the start.

Airships to Orbit? This idea does not depend on them, but I am contemplating one such where the balloon is like an accordion, and that can be deflated and collapsed into a clam-shell type shroud, so that from floatation of a large blunt object you can transition to a thin aerodynamic wing/saucer shape. Maybe round maybe delta. I see it, but there are some issues to work out.

Last edited by Void (2013-04-20 14:29:24)

JoshNH4H · 2013-04-20 19:13:05

Robertdyck-

For the most part, I would say that keeping a thread on-topic isn't an end unto itself and that excessive enforcement of OT rules can stifle discussion. However, seeing as there were two viable threads of discussion in the "Crops" thread I figured it was worth moving the discussion elsewhere.

You claim that polyanhydride, consisting of [-C(=O)-O-] monomer units has already been synthesized. This is false. Polyanhydride, as the wikipedia article itself shows, has the structure:

Where "R" is an organic hydrocarbon. This polymer cannot be made primarily from a CO2 atmosphere; Hydrogen inputs would be necessary and its production would release oxygen, which is actually undesirable in this case because there would just be too much of it (humans can't take more than an absolute max of 1 bar of gaseous oxygen). This is not a copolymer but the polyanhydride itself. The reason is, as I stated previously, that the polymer you're proposing to use is unstable at any temperature. We can arrive at an estimate of its stability at various temperatures using bond energies, obtained using the enthalpies of formation of the following compounds. This is an approximate method but should provide reasonable accuracy nevertheless. The "table" that follows has columns in the form of Compound : Number and Type of Bond : Enthalpy of Formation (source). To be conservative, I think it's reasonable to say that this method should be accurate to within 20% of the values obtained.

Methane : 4(C-H) : -85.1 kJ/mol
Methanol : 3(C-H)+(O-H)+(C-O) : -238.3 kJ/mol
Water : 2(O-H) : -285.6 kJ/mol
Carbon Dioxide : 2(C=O) : -393.4 kJ/mol

Therefore, solving algebraically, a (C=O) bond has an energy of -196.7 kJ/mol and a (C-O) bond has an energy of -74.2 kJ/mol. This means that, per monomer, the transition from [-C(=O)-O-] to Carbon Dioxide will have an enthalpy of -48.3 kJ, meaning that it is energetically favorable. But it gets worse. The number that determines the favorability of a reaction is the change in Gibbs Free Energy, ΔG. ΔG=ΔH-TΔS, where ΔH is the enthalpy just calculated, T is temperature of the reaction, and ΔS is the change in entropy. Negative ΔG indicates a spontaneous reaction. Gases have a higher entropy than solids. The standard molar entropy of CO2 is -213.8 J/mol*k. I could not find the standard molar entropy for [-C(=O)-O-]. I contend that the reason for this is that it doesn't exist. Based on this paper, I will use a value of 20 J/mol of monomers*K, an extremely generous value for such a large molecule. This results in a change in entropy of polymerization of -192.8 J/mol*K.

At standard conditions, the ΔG of depolymerization is -101 kJ/mol. At 735 K, it's -190 kJ/mol. I thus conclude that the existence of this polymer must be regarded with extreme skepticism. Please note that even large errors in the estimation of the ΔH and ΔS result in this same conclusion.

With regards to engineering an organism: By no means do I think that it is impossible. In fact, as I wrote in my post on the topic:

I don't doubt that it will be possible in the long term (perhaps by the time terraformation of Venus begins, I suppose) to do so, but I'm not sure it's reasonable to baseline to that.

Remember: "We haven't proven that it's impossible yet" is not enough for an engineer. Engineers need hard facts and well-tested principles. When the new technology required to do something amounts to a redesign of life as we know it, it is not a matter of simply not being "a bitch," but of a logical cost-benefit analysis in which we question whether or not the technology is worth developing.

Importing 1e19 kg of anything is pretty bad, I agree; And you're certainly approaching the problem from the right angle. But I'm not sure that that angle is ultimately a workable one. It seems reasonable to suggest that there may be water inside Venus; In that case, it becomes less necessary to hypothesize polymers that are unlikely to exist.

Terraformer- You make several very good points. Perhaps it would even make more sense to send it up as pulverized dust, which could make its way to Venus with sunlight pressure (Although I believe I read somewhere that relativistic effects with sunlight actually make dust grains fall towards the sun, in which case that would not work). I would like to point out that Aluminium Oxalate is a compound that exists

Has anyone suggested that a nuclear winter might be a good thing on Venus?

Void · 2013-04-21 10:30:23

Well actually yes.
It appears to me that Venus is balanced by the Sulfur compounds. A dust effect could push it off of that balance, and then some other actions could perhaps cause it to take another path to a different type of stable environment.

Dust from Asteroids? Or could you use mirrors to create a swirling wind storm that reaches to the surface and sucks up dust?
Or bombs?

Here is another trick. Could you mass produce floating bubbles with solar collection? Could those bubbles also have a means to alter the atmospheric chemistry?

My take on the whole Hydrogen thing is you extract it from the Sulfuric Acid and collect it into floating greenhouses, until there is no significant amount of it. It must likely be a type of greenhouse gas itself, just as water is. This will unblock certain wavelengths to radiate out into space. Injection of additional Hydrogen would only heat the place up more.

I believe I saw speculation that when the oceans of Venus are presumed to have boiled off the surface temperature would have risen to thousands of degrees. That may have occurred, and would have continued until the bulk of the Hydrogen was lost to space.

While you could inject constructed small objects into the atmosphere from orbit, it might also make sense to inject dust, to block the sun as well, and to directly absorb the Sulfuric Acid into a compound which would settle to the surface. If the surface temperatures drop in the high mountains, it might be deposited there and stabilize. However then you may loose much of the Hydrogen to the surface.

Another effect of dust might be to alter the PH. It seems reasonable that if you are injecting metals, and that the acid reacts to them, and that collects in the high mountains, then the atmosphere becomes less acid.

In such conditions, I would ponder not a free floating habitat, but platforms on hollow supports, where the hollow supports have floatation properties, but are anchored to the surface. If the upper side of the platforms were cold enough, it is possible to speculate on condensing CO2, as solid or liquid. Also maybe Nitrogen. The purpose? Manufacture it there, drop it by some means to the surface, and you then have a coolant at the surface, and one that can boil and expand, and power robots. Some of them being capable of helicopter actions, or airplane, or steam rocket. (Steams of various things).

Another scheme might involve the possible Lead Sulfide on the high mountains. It may be near its evaporation point, so an alternative would be to heat it up into a gas, and pump it up to where a receiver for orbital beamed solar power could separate out the lead, and drop that to the surface. If the environment of Venus were still a bit acid, then a high temperature lead-acid battery process could power robots.

If you have robots on the surface, then you can access a very large range of materials to construct more robots and floating towers with.

I do say that if it turns out that two companies on Earth can collect small asteroids, then it seems reasonable to me that it could be done near Venus as well, and while much of the materials might be used in orbit, there should be an excess of tailings that could be dumped into the atmosphere of Venus, as dust or floating machines that block the sun.

As for getting rid of the whole atmosphere?

That would have to be a plan for much later. It may be that by the time the above were implemented for Venus (If it were), the inhabitants would be quite happy with a Venus altered to that degree, with habitats on high platforms.

Taken even further, if all the surface were covered by such habitats, perhaps they could shade the ground so much that a CO2 Ocean would condense. They would still need platforms in the sky, I think because the Greenhouse effect from the Nitrogen would be too much without them. But perhaps eventually at that point they could import Hydrogen in Mass, and gradually convert the liquid CO2 to H20 and biomass, and deposit the biomass at the bottom of oceans.

Last edited by Void (2013-04-21 10:42:27)

RobertDyck · 2013-04-21 13:40:15

JoshNH4H, do some more research. Wikipedia is not my only source. Pure polyanhydride has been made, and it has different attributes. Just as high density polyethylene (HDPE) is harder and more durable than low density polyethylene (LDPE), the same applies to polyanhydride. The reason is molecular branching. Polyanhydride manufactured by the pharmaceutical industry is a co-polymer with something that is designed to decompose at a known rate, and to carry the drug it's supposed to deliver. That means branching. So it shouldn't come as a surprise that that form of polyanhydride behaves similar to LDPE. However, pure polyanhydride does not have any branches, so behaves like HDPE. It's harder, denser, can withstand more heat, and more durable. The catch is you need a strong end unit on each end of the polymer chain. If you don't, it'll unravel. The fact it has been characterized demonstrates it does exist, it has been synthesized.

That said the chemistry knowledge you demonstrate is impressive. But just because something can decompose, doesn't mean it can't exist. I'll give a radical example: nitro-glycerine. It decomposes extremely rapidly, yet it does exist as a liquid. As long as you don't expose it to shock, it's stable. There are others that are more stable, will not decompose unless exposed to an explosion. My understanding of polyanhydride is it won't explode, but will decompose rapidly (seconds or minutes) once it has started to "unravel". This material isn't intended to be a super material for anything useful, just to sequester CO2 out of the atmosphere of Venus.

JoshNH4H · 2013-04-21 14:09:40

Robertdyck, can you point me to any sources indicating that a stable polyanhydride exists with the properties that you claim it has?

JoshNH4H · 2013-04-21 14:11:34

Oh, and just to clarify, are you saying that the structural image given on wikipedia and reproduced in my post is incorrect?

StarDreamer · 2013-04-21 16:51:07

Maybe we could convert the atmosphere of Venus to margarine.
Margarine is just one molecule away from plastic....

Just kidding, but it's a fun thought ....

Void · 2013-04-21 17:59:29

I am currently in a fitness challenge currently 18.1% body fat, 17-18% being the low end for my age.

Mmmmmm...... Venus sound yummy.

RobertDyck · 2013-04-21 18:00:45

JoshNH4H wrote:

Oh, and just to clarify, are you saying that the structural image given on wikipedia and reproduced in my post is incorrect?

The image is generic. It has "R" for the co-polymer. That "R" can be anything. Now make it a single oxygen atom.

qraal01 · 2013-04-22 06:07:25

This paper has significance for terraforming Venus: http://arxiv.org/abs/1304.3714

Towards the Minimum Inner Edge Distance of the Habitable Zone
Andras Zsom, Sara Seager, Julien de Wit

...the punch-line being that a desert planet can remain habitable - i.e. able to sustain some liquid water on the surface - up to an insolation ~4 times Earth. The trick is the conditions required to do so at high insolation aren't met on present day Venus, not just because of the thick atmosphere, but also the slow rotation. If Venus rotated quicker then quite high temperature gradients could be sustained and it could, for example, have cold polar caps with above boiling point equatorial deserts. The thermal inertia of the current atmosphere is probably too high presently, but removing the CO2 would leave about ~2 bars N2 on the surface, which would support a habitable climate if the planet rotated quicker. Question is: how fast is fast enough?

Intriguingly it also means that burying the Earth's oceans will allow it to remain habitable well into the deep future. The Main Sequence, by current models, will end with the Sun only about ~84% brighter (x1.84 present day) and even the billion year long Redwards Traverse will only see the insolation climb to ~x2.7 present day. The luminosity will rise a bit more rapidly after that, then do a mad scramble towards the Red Giant Tip - when the Sun bloats to ~256 times bigger and 2730 times brighter than today. All crammed into a few million years! A Desert Earth might remain habitable to about 7 billion AD or so.

JoshNH4H · 2013-04-22 07:36:37

RobertDyck wrote:

JoshNH4H wrote:
Oh, and just to clarify, are you saying that the structural image given on wikipedia and reproduced in my post is incorrect?
The image is generic. It has "R" for the co-polymer. That "R" can be anything. Now make it a single oxygen atom.

No, that's not correct. "R" cannot be anything. "R" refers specifically to Hydrocarbon groupings. It wouldn't make sense to refer to any possible substituent with one representation because different substituents would have different chemistry*. One could see how this compound would be stable with an alkyl group, because then it becomes in essence, a poly-ester.

That is not the formula for a copolymer, by the way. That is the article on Polyanhydride. That is the general formula for polyanhydride in its pure form.

You say you have sources. I am willing to concede this point the moment you present me with a valid source that supports your claim. I have not myself been able to find any, so if you could direct me to one I would really appreciate it. I would be very happy if there were some stable compound made from Carbon and Oxygen in a 1:2 mole ratio (I suppose higher amounts of Oxygen wouldn't be a problem since Carbon is a solid), perhaps with other elements that are indigenous to Venus but I don't think that this polymer is it.

*Examples abound. Take the representation of an alcohol: R-OH. If R could, as you say, be anything, this could be the formula for Hydrogen peroxide or water, both of which are clearly not alcohols. For that matter, it could be NaOH or NH4OH. These are obviously not alcohols either.

Qraal, that is very interesting. Do you have any sense of how much land area one would get from Venus if it were transformed into that kind of desert planet?

Welcome back, by the way.

qraal01 · 2013-04-22 14:27:05

JoshNH4H wrote:

Qraal, that is very interesting. Do you have any sense of how much land area one would get from Venus if it were transformed into that kind of desert planet?
Welcome back, by the way.

Thanks Josh. As for land area, most of it. The humidity has to remain low, so we're talking <10% water coverage of the planet. Roughly. So such a Venus would be very dry compared to Earth, but as we use only a tiny fraction of the water we have, it's more a matter of water useage efficiency. As the equatorial and tropical regions would be very hot, all the water bodies will be clustered around the poles. A scenario might result in which canals linking the two polar regions are dug, probably requiring coverage to reduce evaporation.

Void · 2013-04-22 18:45:31

qrall01 I appreciate that you provided that article also. A great addition, more dimensions. For instance spin.

So, if it is not feasible to increase the spin of Venus, could the humidity of Venus be throttled down further, containing water in habitats only. I presume the spin is needed so that the polar water has time to cool down so that it does not actually boil humidity into the atmosphere. Covering it with a shading? I believe plants can grow successfully with 10% Earth light so on Venus you would let 5% through the shaded moist locations?

I had heard of these desert planets, but only the most vague reference to this point.

Is it reasonable to say that Sulfuric Acid along with such water vapor as is present, is one of the keys to the current high temperatures of Venus?

It looks to me that a pathway if found between the current stable condition, and a preferred new stable desert planet condition, might involve a sequence of manipulations. I can only offer that removal of Hydrogen from the atmosphere, and therefore H20 vapors and Sulfuric acid vapors might help to lead to an initial cooling, along with that dust could improve that situation, and I might hope that a cooling surface might absorb some atmospheric gasses. (The reverse has been proposed for a Mars where the surface is warming, that gasses would be released).

StarDreamer · 2013-04-22 19:42:34

I am certain it has been worked out that a cooler Venus with less mass in its atmosphere would gain spin naturally, much like a ice skater drawing in her arms to her body.

Terraformer · 2013-04-23 04:28:43

It won't be significant though. The angular momentum contained in the atmosphere is far, far less than that contained in the planet itself.

qraal01 · 2013-04-23 04:38:48

Void wrote:

qrall01 I appreciate that you provided that article also. A great addition, more dimensions. For instance spin.
So, if it is not feasible to increase the spin of Venus, could the humidity of Venus be throttled down further, containing water in habitats only. I presume the spin is needed so that the polar water has time to cool down so that it does not actually boil humidity into the atmosphere. Covering it with a shading? I believe plants can grow successfully with 10% Earth light so on Venus you would let 5% through the shaded moist locations?

The spin is needed to sustain a temperature gradient so the pole remains cool. Else a slow atmosphere would mix too well and heat everything evenly - ala current Venus.

Void wrote:

I had heard of these desert planets, but only the most vague reference to this point.
Is it reasonable to say that Sulfuric Acid along with such water vapor as is present, is one of the keys to the current high temperatures of Venus?

No. Clouds are a double edged sword in a sense, but the H2SO4 layers reflect heat away on current Venus more than they trap. The real problem is all that CO2 which enhances its own heat-trapping by pressure-broadening the spectral windows it absorbs best at.

CO2, at lower pressures, helps cool the very high atmosphere and trap in the water, keeping the planet wet. We want much lower CO2, but not too low. More importantly we don't want too much water, else a runaway Greenhouse will result from self-accelerating evaporation of the oceans.

Void wrote:

It looks to me that a pathway if found between the current stable condition, and a preferred new stable desert planet condition, might involve a sequence of manipulations. I can only offer that removal of Hydrogen from the atmosphere, and therefore H20 vapors and Sulfuric acid vapors might help to lead to an initial cooling, along with that dust could improve that situation, and I might hope that a cooling surface might absorb some atmospheric gasses. (The reverse has been proposed for a Mars where the surface is warming, that gasses would be released).

Dust absorbs as much as it reflects, unless engineered right. Really what Venus needs is for about 99% of the CO2 to become a convenient solid and fall out of the sky. The sulfuric acid will react with the regolith and basically neutralise itself, once it can condense on the ground at about ~500 K. What remains will be the equivalent of about 10 centimetres of water over the whole surface - enough for a smallish lake. Not enough to make trouble.

Void · 2013-04-23 08:43:46

I defer to you on the spin, it is good to get the correct answer on that. I will incorporate it.

Void wrote:
I had heard of these desert planets, but only the most vague reference to this point.
Is it reasonable to say that Sulfuric Acid along with such water vapor as is present, is one of the keys to the current high temperatures of Venus?
You wrote:
No. Clouds are a double edged sword in a sense, but the H2SO4 layers reflect heat away on current Venus more than they trap. The real problem is all that CO2 which enhances its own heat-trapping by pressure-broadening the spectral windows it absorbs best at.
CO2, at lower pressures, helps cool the very high atmosphere and trap in the water, keeping the planet wet. We want much lower CO2, but not too low. More importantly we don't want too much water, else a runaway Greenhouse will result from self-accelerating evaporation of the oceans.

I will continue to argue on this point because I think I have a responsibility to dispute it as an absolute.

http://www.esa.int/Our_Activities/Space … _and_winds

Please don't see this as a hostile rebuttal, rather as conflicting argument.

On the global scale, Venus’s climate is strongly driven by the most powerful greenhouse effect found in the Solar System. The greenhouse agents sustaining it are water vapour, carbon dioxide and sulphuric acid aerosols.

The point I am making is not for the purpose of disputing that it can be possible to remove CO2 by the means suggested in previous planning, but to say that indeed a significant portion of the greenhouse effect, (Even though less than the massive volume of CO2), is from the water vapor and the Sulfuric Acid content.

I do recall a very long time ago seeing a TV program where it was stated that the CO2 by itself cannot elevate the temperatures as high as they are, but that a combination of gasses is responsible for blocking wavelengths from radiating from the planet.

While I do not yet see how a removal of Sulfuric Acid and Water Vapor can be compatible with the organic method of removal of CO2 which is being discussed, each removal should help. The trick would be to find a way. Since Sulfuric Acid is often hostile to life, removal of it might help.

I still enjoy your contribution here to a very large degree. I am very pleased to interact with you.

As for my credentials, I am only an enthusiast on the subject, and it is often a very tricky think to know when I should argue, or be silent, since I am inclined to believe that quite a few of the posters here are very well credentialed.

Perhaps some of my information is outdated, and now proven wrong, but I cannot update my facts without interaction.

I also note that habitation of the upper atmosphere by machines or humans would be more possible without the Sulfuric Acid, so it is a target I am interested in.

And to impede a summary dismissal of my prior post, I also re-ask the question:

If it is not possible to increase the spin of Venus after terraforming, and on the basis of the evidence you posted, rather than having open water at the poles of Venus, would it be possible to have enclosures for the moisture at the poles, strongly shaded to perhaps 5% of the solar flux, where habitat could be provided.

The purpose would be to keep water vapor below 1% in the atmosphere of Venus, but elevated inside of the habitats.

Since the model for habitable desert worlds cannot include even an improved Venus with open water at the poles without increasing it's spin.

Last edited by Void (2013-04-23 09:07:35)

karov · 2013-04-23 11:14:06

Which is easier - to spin a planet, or to bend rays of light paths?
Also we are not sure that slowly spinning world won't have nice climate.

Void · 2013-04-23 17:03:59

Qraal01 made an excellent post yesterday with a link to a site with answers to that.

If I understood;
1) A greater rotation than Venus now has would be needed, to provide atmospheric isolation for the polar regions, so that the moisture of them would tend to stay there, and not humidify the lower latitude atmosphere.
2) A humidity of 1% in many cases could allow such a planet to be habitable even at a distance of .5 AU.

Beyond that we do not have convergence. However that is quite a lot.

Void · 2013-04-23 22:53:45

Natural CO2 lasers on Mars and Venus:
http://laserstars.org/history/mars.html

http://kategreene.net/?p=764

Anyway I looked that up after thinking about building lasers on the surface of Venus.

I am not sure how possible the notion is, but it is largely a CO2 atmosphere, so CO2 Laser.

The typical materials used for the mirrors may handle the temperatures OK.

Dealing with corrosion will be a problem.

I suppose I am thinking that since Venus is almost hot enough to glow in visible wavelengths, and CO2 Lasers are infrared, some of the needed requirements are met.

A use for it? Maybe to refine metals?

Well actually I was wondering if they could point up, and with heat punch a hole in the clouds, or otherwise cause localized convection, with the hopes of altering the environment.

Perhaps dissipating a bit of heat to space, but perhaps more importantly if causing atmospheric convection, then causing hail or cold rains to then fall from clouds elevated to a higher region in the atmosphere.

Perhaps also maybe being a component in a scheme to alter the atmospheric chemistry, that being done perhaps along with adding some chemicals to the cloud mix.

Nothing definite, and no assurance that such lasers could be possible or could endure the environment, or do anything useful, but it is a different idea.

karov · 2013-04-24 00:14:03

http://en.wikipedia.org/wiki/Laser_cooling ?

... if the entire atmosphere of Venus is turned into giant CO2 laser, couldn't the radiation flux be used to cool it down to total freezing of the gases which to settle on surface in more convenient for export solid form?

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