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Githyanki
2012-Jan-03, 02:54 AM
So, if you could have nano-bots convert Venus' atmosphere into water, oxygen and nitrogen to terraform the planet, would the air-mass converted be too much for the world, e.g., would say, it produce so much water that it would cover the planet completely or too much atmosphere? Would the nano-bots have to remove or convert some of the air-mass molecules into other substances like carbon etc.?

Noclevername
2012-Jan-03, 03:28 AM
The CO2, Venus' primary atmospheric component, could split into a massive amount of carbon and oxygen-- way too much oxygen, more than enough to be toxic to any life we know. It would have to be sealed away. Carbon can be made into some fairly inert forms, and would be the primary building and technological material for Venusians. There would also be large amounts of sulfur. The remaining nitrogen, and hydrogen made into H2O, would form just about the right amount of air and water to make the planet fairly Earthlike (not counting spin and the like). The consensus seems to be to lock the excess up in diamond, and/or to export the materials to help build other colonies.


Some previous threads on the topic:

http://www.bautforum.com/showthread.php/39771-Terraforming-mars-or-venus-which-ones-better.
http://www.bautforum.com/showthread.php/59240-How-much-quicklime-would-it-take-to-terraform-Venus? (http://www.bautforum.com/showthread.php/59240-How-much-quicklime-would-it-take-to-terraform-Venus)
http://www.bautforum.com/showthread.php/59971-Making-Venus-livable
http://www.bautforum.com/showthread.php/57487-Terriforming-part-of-Venus

See also the "similar threads" at page bottom.

Van Rijn
2012-Jan-03, 04:13 AM
There was quite an extensive discussion of the issues involved in terraforming Venus in this thread:

http://www.bautforum.com/showthread.php/59971-Making-Venus-livable

As was discussed there, most of the carbon and oxygen would need to be sequestered or removed from Venus for anything close to an Earthlike atmosphere. Venus has very little hydrogen and would require massive imports of water or hydrogen if you wanted anything approaching an Earthlike hydrological cycle.

Noclevername
2012-Jan-03, 04:31 AM
Venus has very little hydrogen and would require massive imports of water or hydrogen if you wanted anything approaching an Earthlike hydrological cycle.

Venus has hydrogen bound into hydrogen sulfide and sulfuric acid-- enough to form rain. If there's enough energy and molecular tech to split all that CO2, there should be something to spare to split these compounds as well, as well as to free any hydrogen bound into the surface. Would there be enough hydrogen from those sources?

astromark
2012-Jan-03, 06:05 AM
So, the raw material 'might' be available.. or not.. Just How would this be done ?

When the tempestuous conditions and the contents of that atmosphere is such

that no man made craft has yet survived the hostile conditions for more than a few hours at best..

That the chemical make up would need such a massive tweak

is so far beyond humanity I can not imagine it ever being done or doable.

and I ask for why some of you think its doable.. or even possible.

Van Rijn
2012-Jan-03, 06:31 AM
Venus has hydrogen bound into hydrogen sulfide and sulfuric acid-- enough to form rain. If there's enough energy and molecular tech to split all that CO2, there should be something to spare to split these compounds as well, as well as to free any hydrogen bound into the surface. Would there be enough hydrogen from those sources?

No, I'm afraid not. If the surface was impermeable you could get maybe a hundred inches of water on average. That would require *perfect* sealing. If you don't have perfect sealing, it's only enough to slightly hydrate the rock - most of it wouldn't even stay as water. It would make Dune look like a waterworld.

Noclevername
2012-Jan-03, 07:29 AM
That would require *perfect* sealing.

Since the scenario in question involves all of the available surface to be coated with diamond, that's exactly the case proposed.

Noclevername
2012-Jan-03, 07:32 AM
and I ask for why some of you think its doable.. or even possible.

No one said it was either. We're simply answering the hypothetical question posed in the OP. Hence the OP's use of the word "if".

So, if you could have...

korjik
2012-Jan-03, 09:04 AM
Since the scenario in question involves all of the available surface to be coated with diamond, that's exactly the case proposed.

Not alot of agriculture on a diamond surface...

Van Rijn
2012-Jan-03, 09:07 AM
Since the scenario in question involves all of the available surface to be coated with diamond, that's exactly the case proposed.

Okay, so you get a slightly moist planet sized diamond in that case, but I'd hardly call that terraforming. If you want something decent, water (or at least hydrogen) would need to be imported.

Noclevername
2012-Jan-03, 09:12 AM
Not alot of agriculture on a diamond surface...

If this scenario ever becomes remotely plausible, which I personally doubt, it will be because we have molecular manipulators as effective as anything biology could produce. Therefore given the proper elements, food could literally be built at the molecular level by the same nanotech we use for terraforming, thus eliminating the need for agriculture.

Noclevername
2012-Jan-03, 09:16 AM
Okay, so you get a slightly moist planet sized diamond in that case, but I'd hardly call that terraforming. If you want something decent, water (or at least hydrogen) would need to be imported.

Hey, I didn't set the ground rules, the OP did. If you have an alternate plan, go ahead.

Van Rijn
2012-Jan-03, 10:50 PM
Hey, I didn't set the ground rules, the OP did. If you have an alternate plan, go ahead.

I'd suggest rereading the OP. You seem to be confusing your own ideas with the OP's question (which has been the focus of my comments).

Noclevername
2012-Jan-04, 12:09 AM
I'd suggest rereading the OP. You seem to be confusing your own ideas with the OP's question (which has been the focus of my comments).

Really. The OP asks about converting or removing excess materials. I see nothing there about adding materials.

Githyanki
2012-Jan-04, 12:33 AM
As was discussed there, most of the carbon and oxygen would need to be sequestered or removed from Venus for anything close to an Earthlike atmosphere. Venus has very little hydrogen and would require massive imports of water or hydrogen if you wanted anything approaching an Earthlike hydrological cycle.

Just too clarify, I'm assuming the nanobots can "Create" elements on a molecular level. They can simply convert CO2 into water. by rearranging its atomic structure.

Noclevername
2012-Jan-04, 12:42 AM
Just too clarify, I'm assuming the nanobots can "Create" elements on a molecular level. They can simply convert CO2 into water. by rearranging its atomic structure.

Nanobots can't convert elements, no. They can move atoms around, and hypothetically build or separate them into molecules, but they can't change one type of atom into another.

Van Rijn
2012-Jan-04, 02:26 AM
Just too clarify, I'm assuming the nanobots can "Create" elements on a molecular level. They can simply convert CO2 into water. by rearranging its atomic structure.

Not possible. If you wanted more hydrogen on Venus without imports, you'd need to use transmutation with some type of particle accelerators or reactors, and it would be very energy intensive. Nanotechnology isn't going to do it, and realistically, importing the hydrogen would be a much more practical option.

ravens_cry
2012-Jan-04, 02:55 AM
I think the biggest hurdle is speeding up the rotation. I can imagine some form of self replicating probe that sequesters carbon and possibly other elements and creates more. Whether you do this with nanomachines or some kind of engineered life or with a clanking replicator (http://en.wikipedia.org/wiki/Clanking_replicator), it could be conceivable. But speeding up the rotation to even close to Earth-like speeds is another matter entirely.
How would it even be gone about?

Van Rijn
2012-Jan-04, 03:20 AM
Really. The OP asks about converting or removing excess materials. I see nothing there about adding materials.

You're kidding.

Van Rijn
2012-Jan-04, 03:38 AM
I think the biggest hurdle is speeding up the rotation. I can imagine some form of self replicating probe that sequesters carbon and possibly other elements and creates more. Whether you do this with nanomachines or some kind of engineered life or with a clanking replicator (http://en.wikipedia.org/wiki/Clanking_replicator), it could be conceivable. But speeding up the rotation to even close to Earth-like speeds is another matter entirely.
How would it even be gone about?

You don't. It's too difficult, and could have nasty side effects (like a global resurfacing event). Use mirrors (maintained by the clanking replicators or other machines) instead.

I'll point out that this is one of the common issues that comes up often in terraforming threads. For those interested, I'd suggest reading a few pages of this thread:

http://www.bautforum.com/showthread.php/59971-Making-Venus-livable

ravens_cry
2012-Jan-04, 10:45 AM
Yeah, I believe I made a few contributions to that thread. Of course, making Venus liveable is comparatively easy compared to terraforming thanks to a number of factors.

neilzero
2012-Jan-04, 09:13 PM
We seem to agree that there is only enough hydrogen to terriform a small portion of Venus, but too much oxygen and carbon. The carbon surplus is easier, as it can be charcoal, soot, graphite, coal, carbides, humus, CNT, graphine and/or diamond. Someone calculated that there was enough carbon to cover the entire surface of Venus to a depth of 600 meters. As charcoal dust, it would fill the valleys and low places to a depth of several kilometers, and all the hydrogen would make enough water to make the charcoal damp, not wet = liveable with high tech, but not Earthlike which is the usual definition of terraform.
One of the first projects would be to sequester the sulpheric acid = Perhaps nano bots can collect the acid and store it in about a million large tanks. We will likely need it later, but it is a hazard early in the terraforming. It will likely be helpful to cool the surface temperature from about 500 c to about 400 c to keep the various kinds of nanobots healthy. 400 c might allow the very acid rain to reach the surface, which will likely make the acid collection perhaps more difficult.
We can imagine nano bots that can fision oxygen and carbon = the reverse of red giant stars. The fision of only a few isotopes produces energy = fision of oxygen and carbon requires energy = enormous amounts of energy = 70% of all the solar energy that falls on Venus in millions of years = about a million times too long to interest investors in the project of terraforming Venus. With only 30% of the sun's energy heating Venus, it would cool to comfortable temperatures in a few decades, possibly sooner. We have only foggy ideas of how to do any of this even small scale and the scale of Venus is huge.
To make Venus possibly livable, we can make the surface of Venus impervious, install statite sun shades a few million kilometers from Venus and cool the surface to about 30 degrees c, then it will rain liquid carbon dioxide, which will make lots of carbon dioxide lakes. The pressure and temperature are possibly tolerable for humans, but the atmosphere will now be about 50% carbon dioxide, and 50% nitrogen. Lots of things are soluable in liquid carbon dioxide, so we should likely install an impervious layer on top of each lake to minimize further contamination. Further cooling will not condense more carbon dioxide nor lower the pressure significantly as carbon dioxide does not have a liquid state except at moderately high pressure. Likely essentially all the hydrogen is in the million large tanks of sulpheric acid otherwise we would get water rain, that would float on top of the impervious layers on the liquid carbon dioxide lakes. We can extract hydrogen and water from the sulpheric acid, but it may be better to import hydrogen from off planet. We have dangerous amounts of oxygen in the atmosphere if we separarate most of the remaining cabon dioxide gas. We will likely need some statite sun shades until our sun is a white dwarf in 4 or 5 billion years, to keep Venus at a comfortable temperature, even if we get the carbon dioxide down to 0.02% which is about the least green plants can tolerate. Most green plants also need at least a trace of oxygen, which will be a fire hazard at more than about 1%. Even diamond burns like coal if you get it started burning. Neil

neilzero
2012-Jan-04, 11:27 PM
Early in the make Venus livable thread nocleavername and some others suggests using Megamaid to vacuum the atmosphere away from the surface: Suction won't work. Pumping the air up a pipe from the surface might work if the pipe is strong enough and reaches about a thousand kilometers above the planet. With a 200 kilometers long pipe most of the gas would eventually be recaptured by the gravity of Venus.
If we build a road all the way around Venus, near the Equator and only permit travel in the direction opposite to the rotation, Venus will speed up minutely with each lap of each vehicle. In a few trillion years Venus would have a 24 hour day, if the traffic was heavy and it was rare anyone traveled the opposite way, anywhere on Venus.
Yes, lowering the surface air pressure would possibly trigger a resurfacing event, but cooling the surface slowly, might delay resurfacing.
Since the surface is presently at 500 c cooled from about 1000c at the last resurfacing, the hydrogen content of the surface may be as low as one part per million, and very difficult to extract.
Too much water is very improbable even if nearly all the carbon dioxide is converted to water. Perhaps 10% of the surface would be water covered. Perhaps not enough for a good hydrologic cycle. Neil

ravens_cry
2012-Jan-05, 12:46 PM
If the turbulence isn't too bad, why terraform at all when you can live in oxygen balloons formed from carbon allotrope's? Ironically for such a hellish surface proper, Venus is surprisingly congenial in the upper atmosphere, having pressures and temperatures that are quite Earth like.
In fact, aside from protection from the clouds of acid, (what would be required?) you only need a gas mask to survive. Energy is plentiful thanks to comparative nearness of the Sun and certain asteroids are favourable from a Delta-V perspective. Its gravity well is an issue, but the thick atmosphere is excellent for aero-braking, and that same high gravity, hopefully, means fairly little, if any health issues for apelings adapted to Earth gravity.

Robert Tulip
2012-Jan-05, 01:31 PM
And meanwhile, we may be steadily venerealising earth as we head towards a runaway greenhouse with accelerating emission rates...

Is venerealise the correct cognate for terraform?

Noclevername
2012-Jan-06, 01:23 AM
You're kidding.

What do you mean?

neilzero
2012-Jan-06, 04:19 PM
~The following is my post of 3.2 years ago~
With mistakes made in terraforming Venus, there will likely be details that still need fixing after a million years at a billion dollars per year = 1000 trillion dollars. We likely will not start, unless we are over optimistic. We can, however, start spending the money now. We can develop the sun shades for Earth to later be towed to Venus when Earth gets too cold. For best results the shades will allow the wave lengths best for algae photosynthesis to pass while blocking or reflecting most of the other wave lengths. We can genetically alter the algae for best performance in the Venus upper atmosphere. If the algae can fly, they will fix more carbon dioxide before they are scorched by heat and acid as they drop lower into the atmosphere of Venus. We can plan the first human outpost in the cloud tops of Venus. We can start the development of robots that can work on the hostile surface of present day Venus. We can develop the technology to send comets from the Oort cloud to crash into Venus. We can gather more data about the Oort cloud and Venus, so we make fewer engineering errors.
My tentative plan is to build a snow fence (It is realy a dust fence) that approximates the Arctic circle of Earth, but perhaps with a circumfrence as short as 3141 kilometers = diameter 1000 kilometers. With the pole shaded, Venus will have a polar down draft which will remain centered on the North pole as Venus is tited on it's axis less than two degrees. The algae will be carried by the upper winds and be brought to the surface near the North pole as algae charcoal, later algae humas, if the shades can cool the north pole sufficiently. The first 10,000 years the algae will not burn as it will take the algae more than 10,000 years to get the atmosphere of Venus to 1% oxygen. Venus has an enourmous amount of atmosphere. The snow fence will keep the dead algae and unused fertilizer from being pushed off the polar platau by the South bound surface winds.
In 100,000 years the platau will be miles higher than the rest of Venus which will help make the polar platau cooler. We will likely need the sun shades until our sun becomes a white dwarf in 5 or 10 billion years.
At about 100,000 years, before the first rain reaches the surface, robots and/or genetically altered humans, will cover the entire polar platau with an impervious layer. The platau will be slightly bowl shaped because the snow fence will concentrate the dust near the edge. Now the acid rain makes a sea of wet dust on the impervious layer which will prevent the acid from escaping the platau This period will be difficult for both gentically altered humans and robots because of the strong acid rain. It will be necessary to repeat the impervous layers to keep the acid traped forever between the impervious layers. After another 10,000 years or more, all the acid in the Venus atmosphere will be sequestered between impervious layer in the great polar platau. Hopefully, the weight of the platau will not cause Venusquakes. Now fresh rain will fall on the platau and food crops can be grown. We brought lots of water to noursh the algae over the past 10,000 years. The rest of Venus is still 500 degrees c = 932 f, so we need to keep the polar down draft strong or very hot surface winds will occasionally blow into the high polar platau, causing great misery. A mile high wall can be built of material that passes the wave lengths best for photosynthesis, if the down draft is insufficient to keep out rare North bound surface winds. The Sun is always close to the horizon at the top of the polar platau, so some mirrors are likely necessary to allow photosynthesis on the surface during winter.
So the temperature is comfortable for naked humans, we can grow crops, because we have rain, but we are still about 1/3% oxygen and 90 percent carbon dioxide. 1/3% oxygen is ok as that is about the same oxygen partial pressure we have on Earth if the air pressure on the Venus platau is 66 bar instead of the present 90 bar. The genetically altered humans will need a prothesis to remove carbon dioxide from their blood, as lungs cannot do that if the ambient is 90% carbon dioxide. We may need some additional alterations to tolerate 66 bar of air pressure. Venus has about the same amount of nitrogen as Earth, but the present percent is about 1%. ~New data suggests 3 times the nitrogen of Earth~
We can do the South pole the same way, but the North pole already has a range of high mountains close to the North pole. At about 100,000 years we can decide if we want to continue the costly algae program, or wait a billion years for the platau crops to lower the carbon dioxide to about 0.04 % The impact of comets, near the Venus equator is a signifcant risk to the colinists on the platau as misguided comet could hit the platau. A billion humans can live on an 800,000 square kilometer Venus polar platau.
~Now I think the million years is optimistic without lots of scientific and technial progress, which may occur in this century. The carbon dioxide sequestered in diamond spheres may be practical, and we are presently experimenting with gas in CNT = carbon nanotubes. Cheap CNT is likely the main holdup. Neil~

hypergreatthing
2012-Jan-06, 05:51 PM
I know this is a huge what if, but can nano bots + solar winds (which i assume are mostly hydrogen particles) and lets say, thousands of years with a huge engineering structure to capture the solar winds, combine them with the CO2 in the atmophere and create water (with the captures hydrogen) and lets say, complex carbohydrates stand a chance of terraforming venus?

neilzero
2012-Jan-06, 07:41 PM
Earth's and Venus' upper atmosphere has been hit by these hydrogen nuclei for 4 billion years. Perhaps that acounts for several percent of Earth's water. They travel at about 500 kilometers per second, so it seems unlikely that they can be collected by nanobots, but perhaps they can be collected over a much larger area than Venus. Perhaps hydrogen nuclei plus CO2 plus electrons (which are also in the solar wind) = complex carbohydrates which I suppose are useful, except they would be contaminated by other stuff in the solar wind. Neil

hypergreatthing
2012-Jan-06, 08:10 PM
Earth's and Venus' upper atmosphere has been hit by these hydrogen nuclei for 4 billion years. Perhaps that acounts for several percent of Earth's water. They travel at about 500 kilometers per second, so it seems unlikely that they can be collected by nanobots, but perhaps they can be collected over a much larger area than Venus. Perhaps hydrogen nuclei plus CO2 plus electrons (which are also in the solar wind) = complex carbohydrates which I suppose are useful, except they would be contaminated by other stuff in the solar wind. Neil

Well i figured if you're going to build a huge solar shield to filter the sunlight (probably needed to make Venus really human habitable) it could double as a solar wind collector as well. I wasn't suggesting that the nanobots released in the atmosphere would collect the solar winds, but they would use the material that was collected to do their chemistry changes on a global scale.

Githyanki
2012-Jan-08, 12:42 AM
Not possible. If you wanted more hydrogen on Venus without imports, you'd need to use transmutation with some type of particle accelerators or reactors, and it would be very energy intensive. Nanotechnology isn't going to do it, and realistically, importing the hydrogen would be a much more practical option.

How is it not possible?

Van Rijn
2012-Jan-08, 02:03 AM
How is it not possible?

It's not possible because what you're asking for would require nuclear transmutation, not chemistry. Nanomachines could do chemistry, but not strip neutrons off nuclei.

Githyanki
2012-Jan-08, 09:16 PM
Why not? If you can machines that can strip and rearrange the atoms, surely you can create anything out of anything even if the nano-machines would have to build a super-conductor to do it and solve a 25th century problem with 20th century technology.

Van Rijn
2012-Jan-09, 12:01 AM
Why not?


I already explained why not. Your statement was, 'I'm assuming the nanobots can "Create" elements on a molecular level' but your assumption is wrong. Further, even with a particle accelerator (not nanobots), the energy requirements would be ridiculous. And I mean ridiculous even if you assume you have solar panels larger than the planet.

Githyanki
2012-Jan-09, 10:57 PM
Alright then, in the future I believe they can; prove me wrong.

neilzero
2012-Jan-11, 01:31 AM
Hi Githyanki: If we build a Dyson sphere with a radius of 2 AU. Perhaps we have enough energy to convert 1% of the carbon dioxide on Venus to water in a trillion years; maybe only a billion years if we can improve the efficency of a Cern type accellerator by 1000 times. Worse we likely used the mass of Venus and most everything else to build a Dyson sphere, and accellerator, that big. I'm not sure, but I think the Sun's photosphere will get much hotter, if the Dyson sphere reflects only 1% of the solar energy back at the Sun = 99% absorbtion. Neil

Delvo
2012-Jan-11, 07:20 PM
Alright then, in the future I believe they can; prove me wrong.Simple. Transmuting elements requires adding energy or releasing energy, because two atomic nuclei with different numbers of nucleons in them are at different energy states... and the amount of energy in question is not only far more immense than a nanobot could ever hope to come anywhere near being able to store or manipulate, but for that matter, it's also more than it could hope to even survive at all instead of just getting reduced to particles itself if it were even anywhere near the area where that kind of energy transfer happened. Nuclear bombs work by causing comparable reactions in only a relatively small handful of atoms, and you're talking about doing it to an entire atmosphere, essentially treating it as 4.81020 kg of nuclear fuel. We're talking about something more comparable to the output of stars than to that of small robots. Not only would nanobots or any other kind of robots be unable to work with such energy levels, and be turned to plasma themselves if such a magnitude of energy transfer happened anywhere near them, but it's also so much energy that the entire planet's temperature would increase radically, blowing off the whole atmosphere (including the more volatile metals along with it, since they'd also be vapor at this point) and rendering the entire surface orders of magnitude more radioactive than any nuclear weapon detonation site on Earth has ever been. The only things I'm not sure about, without actually trying to run the precise calculations, are whether the planet's surface would entirely liquify or vaporize, and whether the excess radiation coming from Venus would be harmful to life on Earth.