Rapid Terraforming... - ...the most ambitious ideas?

Rxke · 2003-11-24 03:42:59

Thanks, Shaun!

Actually, I've read a lot into the subject, (since i was a teen...) but was not sure wether you people were thinking about using CFC or not... Sometimes i'm too lazy to look up the acronyms *again* (They differ between languages, CFC=CFK in Dutch etc... So if was not certain PCF was also CFC...) so i was kinda confused. Sorry 'bout that.

(Read *somewhere* not here i think, about efforts to use CFC anyway because it would be easier to produce, initially, then later scrubbing it *again*, but that makes little sense IMHO... You'd have to force life to re-re adapt to new situations, could be difficult....)

*Do you really think a soletta is such a good idea? What if, after years of life adapting to the new energy and light-levels, it would fail? (massive tear or something like that) Wouldn't that trigger a global (Martian) die-off of plant-(and animal) life? An eco-system not dependent on this soletta would be much more robust in the long run, given enough time to settle its niches... Depending for a big deal on such a flimsy (litt) structure for terraforming is taking a big risk, considering Mr. Murphy interplanetary law...

Shaun Barrett · 2003-11-24 04:43:20

Rxke:-

Sorry 'bout that.

Please, Rxke, there's absolutely no need whatsoever for apologies. As it happens, I was completely unaware that english is not your first language and, if anything, I should apologise to you!
Your grasp of english is quite superb and exceeds my knowledge of dutch by many orders of magnitude!
I always feel humbled by people such as yourself, Gennaro, and Dickbill etc., whose linguistic skills far exceed my own and who manage to express themselves so well in a language other than the one they were born to.

It's small wonder that there's confusion in your mind between CFKs, CFCs, PFCs etc. I have plenty of trouble with acronyms such as these in my own language, without having to translate them into dutch!!!

As for the soletta, I think it may prove to be a necessity because of the topography (shape) of Mars. If a new ocean is created by melting all or most of the water frozen into the regolith (soil), it will accumulate in the northern hemisphere and be centred, more or less, on the north pole.
Even here on Earth, with more than twice the insolation of Mars, and with a far denser atmosphere to trap the heat, we have a permanently frozen Arctic Ocean. There seems little doubt that any Oceanus Borealis created on Mars will be permanently frozen too, unless we do something about it. A frozen ocean in the northern plains of Mars would dramatically increase the albedo of the planet, reflect a great deal of solar heat, and serve to nullify much of the greenhouse effect achieved by artificially created greenhouse gases.
We can't allow that to happen; hence the soletta.
But, as ever, I'm prepared to listen to alternative arguments and would be perfectly happy to abandon the soletta if I can be convinced that it's not required.

Rxke · 2003-11-24 05:29:35

.... I was apologizing for the misuse of bandwidth by me...
I keep repeating it, but... My English LOOKS better than it actually IS. A lot of non-natives read a lot of English, and learn a lot of 'big' words that way, we end up (well, i do...) 'scaffolding' our ramblings around these 'big' words, gives the impression we're really fluent, but that's not always the case...

Ok; on-topic again... Northern hemisphere- ocean... Yes, that's bound to be a problem, (seen the simulations, the fancy graphics, that is...) Wouldn't KSR (red-green-blue Mars) moholes be a solution? They'd be *fairly* easily dug, by robots, and if you dig them on the lowest spots, they'd initially 'only' warm the atmosphere, and then later, when they are flooded, they could keep the water temperate(sp?) Of course, that'd take quite an amount of moholes... Water being hard to warm up... (high caloric value blahblahblah...)

...Might be talking nonsense anyway, the moholes would probably collapse when flooded, and they're just science-fiction ? (or not, has there been research done on them? How much energy could they release... There's been talk recently about a liquid magma layer after all (Mars) so it COULD be an interesting avenue of thought...

*off to Google 'mohole'

EDITED: hmmmm... doesn't look like there's been done much research into mohole tech...

Byron · 2003-11-24 05:59:51

What if we manage to push a 200 km-diameter snowball out of its trans-plutonian orbit but get the sums wrong? It may prove much more difficult to turn aside such a juggernaut than it was to shift it from its original orbit .. remember, it will mass quintillions of tonnes and may reach a velocity well in excess of 40 km/s!!

Crashing a 200 km-diameter object into Mars?? What think I'm crazy or something?!?...lolol. I was thinking more along the lines of the 200-meter range....certainly nothing larger than a kilometer. First of all, it'd be easy for robot craft to attach themselves to objects this size and steer them towards Mars, using reaction mass of the objects themselves and the gravity wells of the gas giants to fine-tune the trajectories of these snowballs. If something went wrong, I would think that they could crash it into Jupiter (which eats comets like the Cookie Monster...hehe), to eliminate any risk to the inner solar system.

Of course, it would take a large number of these things to build up the Martian atmosphere, but at least they wouldn't be so dangerous, plus you would have fine-tuning control over how much to build up the atmosphere, etc.

As for the soletta, KSR describes what happens when the Reds finally take it down for good near the end of the terraforming effort (in the book 'Blue Mars'), which plunges Mars into a more or less permanent Ice Age ??? If one of those things are ever built, it'd better be constructed in a way so that it would never fail, including attacks by potential terrorists! That's the main reason why I'm so "iffy" about hanging large, fragile objects like that in space...too easy for things to go wrong.

As for keeping the northern ocean above freezing, I guess the mohole idea could work, and by re-starting volcanic activity, perhaps this could be one of the ways of regenerating Mars' magnetic field (if such a thing is ever possible). Another idea of mine is to keep the northern ocean as low and shallow as possible, which would provide a warmer climate at the level of where the ocean is...imagine how much hotter Earth's oceans would be if they were two kilometers lower than they are now. (!) But I guess that might be awfully hard to control, since most of Mars will drain into the northern Borealis region...lol...so who knows what would happen if most of Mars' water was thawed out.

B

Shaun Barrett · 2003-11-24 07:13:49

Ha-ha :laugh:

Sorry, Byron. I suppose I did rather jump to unwarranted conclusions about your Kuiper Belt objects!
The reason I did it was because I wanted to get as much volatile material to Mars in the quickest possible time and I kinda assumed that's what was going through your head too.

Your idea of having snowballs no bigger than 1 km across does sound inherently safer but, in order to get the same amount of 'stuff' to Mars as I could transport with my 200 km object, you'd need 8 million of your smaller ones.
Too slow! ... Let's think big here, if we're gonna do it at all!!

Rxke · 2003-11-24 09:13:23

Byron... What about putting a 200km Big One into Mars high-orbit, and cut it to pieces *there?* Wouldn't that be more energy-efficient? You'd only need two or three drivers to get it into orbit, and once it's there, close to 'home,' it'd be more easy to dismantle, and... do some manned explorations on it, to boot...

(you'd lose some stuff due to evaporation, but that'd be cool, imagine the great spectacle that such a close-by comet would bring you, days on end, again and again...)

Byron · 2003-11-24 09:21:13

Yeah, I see both of you guys' points...lol.

Now I'm wondering exactly how many cubic kilometers of frozen volitiles you would need to build up, let's say, a 300 mb atmosphere on Mars. Anyone have any idea of how to calculate this??

B

RobertDyck · 2003-11-24 22:37:32

I would like to see Mars terraformed to the point where colonists could walk outside with nothing more than an oxygen mask and a parka. To do that you need to increase the pressure to at least 2.0 psi (138 millibars) and that would require several weeks of high altitude training and still cause dangerous drying of the lungs. You need 2.5 psi (172.4 millibars) to breathe pure oxygen through an oxygen mask without risk of damaging your lungs. That would still require weeks of high altitude training. Someone used to breathing the concentration of oxygen found on Earth at sea level would require 3.0 psi (206.8 millibars) of pure oxygen.

I was hoping that plants could handle a low pressure as well if the CO2 was at a high concentration. Studies presented at the Humans in Space conference last May indicate that food crops such as spinach require very close to 1 atmosphere. The problem is that plants react as if they are in drought even when there is abundant water. But genetically modified crops are already on the market, so engineering crops to survive the lower pressure of Mars should be easy in a couple decades. The remaining concern is nitrogen. The only nitrogen found on Mars so far is in the atmosphere, and at just 2.7% of an atmosphere so thin it has only 0.7% of the pressure on Earth, that is just not enough nitrogen to support an ecosystem.

Could we convert the atmosphere to something breathable in a short time? Microorganisms multiply exponentially if they are given sufficient nutrients, an energy source, and no predators. Exponential growth could result in such abundance that it could create a breathable atmosphere in just decades. There is already plenty of sunshine on Mars, and no predatory organisms as long as we don't introduce them. The trick is to ensure they have all the nutrients required. There is abundant water, oxygen (in water and CO2), carbon (in CO2), and trace elements. The question is whether there is enough nitrogen or potassium. There is some potassium in Mars regolith, we just have to engineer the microorganism to only require what is available. That leaves nitrogen. Nitrogen is necessary for protein, so you can't genetically engineer away from it. I have argued for designing a colony to only use what we already know is there, but others have argued that there might be a large subterranean deposit of nitrates. Some optimistic souls argue that they must be there. We have found much more water than anyone thought would be there, so who knows, we may find an ancient layer of nitrates. I argued that if nitrates are few and rare, we should not introduce organisms to release nitrogen gas; rather we should mine the nitrates for use as fertilizer on farms. But if nitrates are plentiful we can use them to biologically terraform Mars exponentially.

One thing about engineering a planet is to look at the long term. UV light in an oxygen atmosphere will create ozone, although when ozone absorbs UV it breaks back into oxygen. If left alone an oxygen atmosphere will reach equilibrium with enough ozone so that UV at the surface will be the same as on Earth. However, CFCs in just tiny quantities destroy ozone, so you can't use ozone to terraform. PFCs are just as good to warm Mars but don?t destroy ozone. So if you want to build big chemical factories to generate greenhouse gasses to warm Mars, you have to use PFCs (per-fluorocarbons) not CFCs (chloro-fluorocarbons).

Move Kupier Belt objects to add nitrogen to Mars? Maybe, but be very careful. Use nuclear bombs to rapidly terraform? I don?t have any philosophical objection to it, but the radiation would take so long to die down that Mars would be cold again. Nuclear bombs just aren't practical. A soletta? Maybe. All this indicates we have so many options that a solution will be found.

RobertDyck · 2003-11-24 22:51:19

If you want an atmosphere that will support both plants and humans you must increase the pressure. Plants can be engineered to endure very low pressure if they have very high concentration of CO2. Humans can breathe very low pressure if it is pure oxygen. For humans on Earth at sea level:
0.036% - normal CO2 concentration on Earth
0.1% - Prolonged exposure can affect powers of concentration
0.5% - The normal international Safety Limit
1% - Your rate of breathing increases very slightly but you probably will not notice it.
1.5% - The normal Short Term Exposure Limit.
2% - You start to breathe at about 50% above your normal rate. If you are exposed to this level over several hours you may feel tired and get a headache.
3% - You will be breathing at twice your normal rate. You may feel a bit dizzy at times, your heart rate and blood pressure increase and headaches are more frequent. Even your hearing can be impaired.
4-5% - Now the effects of CO2 really start to take over. Breathing is much faster - about four times the normal rate and after only 30 minutes exposure to this level you will show signs of poisoning and feel a choking sensation.
5-10% - You will start to smell carbon dioxide, a pungent but stimulating smell like fresh, carbonated water. You will become tired quickly with laboured breathing, headaches, tinnitus as well as impaired vision. You are likely to become confused in a few minutes, followed by unconsciousness.
10-100% - Unconsciousness occurs more quickly, the higher the concentration. The longer the exposure and the higher the level of carbon dioxide, the quicker suffocation occurs.
(Reference: Analox)

So you require a high enough partial pressure of CO2 to support plants, with a low enough concentration to not be toxic for humans, with a high enough partial pressure of oxygen for humans. With an ambient atmosphere of oxygen you also need a buffer gas to prevent fires, although CO2 itself will do that. The higher the pressure, the more buffer gas you need. It's a lot easier to design an almost pure CO2 atmosphere sufficient to go outside without a pressure suit. Without a high concentration of oxygen you won't have significant ozone, but if the temperature is still like winter then you'll wear heavy clothing anyway.

RobertDyck · 2003-11-24 23:41:11

Now I'm wondering exactly how many cubic kilometers of frozen volitiles you would need to build up, let's say, a 300 mb atmosphere on Mars. Anyone have any idea of how to calculate this??

Let's see... I like to use 172.4 mb of pressure at the bottom of a valles. It's a lot easier to achieve than 300 mb. So the calculation requires to produce 172.4 mb (2.5 pounds per square inch) literally requires a column of 2.5 pounds of atmosphere to sit on each square inch of land. In metric, 1 bar is equal to 100 Pascals. 1 Pascal is 1 Newton of force over 1 square meter. (1 Pa = 1 N/m^2) One Newton of force is 1 kilogram of mass accelerated at 1 metre per second squared (1 N = 1 kg?m/s^2). Mars equatorial surface gravity is 3.72 m/s^2. To achieve a pressure of 17.24 Pa on Mars you require 4.6344 kg sitting on each square metre of land. That requires 9 billion tonnes of gas. That is to produce 2.5 psi at Mars mean altitude. Lower altitudes will consume more gas than higher altitudes due to the higher pressure, so the formula could get complicated. How many tonnes of dry ice are on Mars? Dry ice has a density of 2.814 kg/m^3 so it would require 3.2 trillion cubic metres of dry ice, or 3,200 cubic kilometres. For 300 mb pressure at Mars mean altitude, just take 300 / 172.4 = 1.740 times as much or 5,565 cubic kilometres.

Shaun Barrett · 2003-11-25 06:53:28

Hi Robert!
I think we're having a bit of trouble with our units here.

1 bar isn't equal to 100 Pascals
1 bar equals 101,325 Pascals

This makes the pursuit of 17.24 Pa of pressure moot because it would give us only 0.00017 bar, or 0.0025 lbs/sq. in.

If 172.4 mb is the required pressure, that translates to 17,468 Pa.
2.5 lbs/sq. in., or 172.4 mb, or 17,468 Pa, is equivalent to 1758 kg sitting on each square metre of land. Taking the surface area of Mars as approximately 145 million sq. km, I calculate our 172.4 mb atmosphere will weigh about 255,000 billion tonnes.

I'm not sure about your density figure for solid CO2, I keep getting 1560 kg/cu. m (?) But that mass of solid CO2, under Martian surface gravitational acceleration of 0.38g, will produce an effective weight of only 592.8 kg. (Always assuming we want more CO2, that is, rather than a nitrogen-rich volatile like ammonia.)

Dividing 255,000,000 billion kg by 592.8 kg/cu.m gives us a requirement of about 430,000 billion cu.m of solid CO2, or 430,000 cu. km.
Of course, this calculation completely ignores the effects of lessening gravitational acceleration with altitude, as was pointed out, so its usefulness is very limited. But I suppose it gives us a vague idea of how big a solid CO2 Kuiper Belt object might need to be.
A spherical object 93.64 km in diameter has a volume of 430,000 cu. km.

Since gravity lessens with distance from the surface, and the area on which the mass of gas acts gets larger, we would need a somewhat larger object than the above calculation indicates.
In addition, the 172.4 mb pressure we've used as our requirement is at the lower limit of human tolerance. I suspect we'll need at least twice that pressure for practical purposes.
At a rough guess, I think we may need 4 or 5 times the volume of solid CO2 (again, this is just for the purpose of this calculation and I understand that ammonia might be preferable), which means we'd have to steer toward Mars a Kuiper Belt object with a diameter of perhaps 150 km, to do the job in one fell swoop.

[P.S. It's getting late so my calculations could be out ... somebody better check 'em! :laugh: ]

Byron · 2003-11-25 07:14:59

And just when I was getting excited over RobertDyck's rosy numbers....<sighs> So we'll be needing a 150-km wide ice ball to do the job, huh? (Or multitudes of little ones...lol.)

I have to agree with you, Shaun, that 172 mb is not really enough for practical purposes...300 mb really should be considered the base-level pressure to shoot for if we're aiming to make Mars human-habitable. The reason why I'm not too excited about having a CO2-dominant atmosphere is that it'd take centuries, if not millenia, to convert this atmosphere to a breathable one...and how to deal with the inevitable cooling that would result from going from a thick CO2 atmosphere to a N-O-dominant atmosphere? And according to current projections of the dry ice inventory on the caps, how many millibars of pressure would we get anyhow if all that were to be converted to gaseous form?

I'm also wondering how much oxygen you can have in a 300-mb atmosphere and still not have to worry about fire danger. Could you have 200 mb of that be oxygen, and the rest nitrogen, CO2 and other gases? Or does the percentage of oxygen (no matter how thin the air is) have to remain below a certain level to prevent runaway fires?

I know I'm asking a ton of questions, but it's awfully nice to have some answers to work with...!

Thanks, guys, for doing all of this brain-twisting math for the rest of us...

B

RobertDyck · 2003-11-25 07:37:14

Well, the unit conversion web site I use www.megaconverter.com/mega2 calculated 1 bar as exactly 100,000 Pascals. Did I slip a decimal point? I was worried about that. Perhaps I shouldn't do math at 11:41pm. I'll check the figures later. I got the area of Mars from the radius. Mars has an equatorial radius of 3,397.2 km according to Solar Views, and the formula for area is 4*pi*r^2. Dry ice density? According to Air Liquide who make and sell dry ice, the density is 1562 kg/m^3. That figure I used was the gas phase density at standard temperature and pressure (STP). I guess I really need to double check my figures before hitting "Add Reply". My excuse is internet withdrawal. My girlfriend doesn't have internet access, the library in her town is closed on Sunday, and the internet at work yesterday was down. I've been "off line" every weekend for a couple months.

However, I still feel we need to do our math for 2.5 psi pressure. The attitude of "multiply the weight by 2 or 3" is how we end up with rockets that don't fly or an OSP that costs 10 times what its worth. The absolute minimum is actually 2.0 psi. According to a US Air Force medical document, when breathing through an oxygen mask pilots who have not gone through high altitude mountain climbing training will become unconscious after 30 minutes. High altitude training can extend the period before unconsciousness, but 2.0 psi is not sustainable. However, 2.5 psi is sustainable for anyone who as gone through high altitude training. That training involves repeated hikes with a heavy backpack up to high altitude where the pressure is low. The process causes your body to grow more red blood cells. The increased density of red corpuscles in your blood carries more oxygen. Climbers who try Mount Everest take week of training up to base camp where the pressure is 1/2 an atmosphere before sleeping there. They carry their supplies on their back to build-up a stash at base camp. They don't use vehicles because they need the exercise to build themselves up for the low pressure on the Everest summit. After sleeping at base camp to get used to it, they start short excursions up the mountain. The peek has a pressure of only 1/3 atmosphere. Oxygen is 21% (by volume) of the air everywhere, so a pressure of 1/3 atmosphere only gives you 1.0 psi partial pressure of oxygen. It turns out you need a greater partial pressure of oxygen if the absolute pressure is very low.

All this means that 2.5 psi pressure on Mars can be handled easily. You only need higher pressure if you want something humans can breathe without an oxygen mask while plants can grow in the same air.

Shaun Barrett · 2003-11-25 08:18:00

I stand corrected on the number of Pascals in a bar. You are quite correct, of course, that it's 100,000 Pa, not 101,325 as I stated.

I usually equate one atmosphere with 1 bar or 1000 millibars, for the sake of simplicity. In fact it's 1013 millibars. Somewhere at the back of my mind, I knew that, but ... well .. I told you you'd better check my figures!!

I'm sure you're right about the survivability of 172.4 mb and I have too little knowledge of human physiology to argue the point, even if I wanted to ... which I don't, by the way.
But I believe there are other reasons why 350 millibars might be better, such as dehydration and radiation protection, though I appreciate that wasn't the point of your argument.

Your warning that making vague guesses ( like my off-hand stab at '4 or 5 times the volume of solid CO2' ) can compromise any calculation quite severely and lead to enormous errors, is well taken.
It was a lame way to end my post and I can't vouch for its accuracy at all, though I tend to think it may not be all that far wrong.
The reason for the guess, of course, is because the mathematics becomes quite complex if you take all the parameters into consideration in a more rigorous analysis. I'm sure there are formulae somewhere which would give us a far better result than my simple doodling, but I'm genuinely curious about the mass of Kuiper Belt snowballs required to produce specific increases in atmospheric pressure on Mars, and just thought I'd throw in my two cents worth in an effort to get an approximate answer.

Now it really is late and way past my bedtime! You don't need a clock ... just check out the extent of my rambling!! :laugh:

~Eternal~ · 2003-11-25 10:42:42

Eh.. I have a question about all this which I'm surpisded no one has asked,
What is the rate of CO2 consumption by 'Oceanis Borealis' ?

dickbill · 2003-11-25 11:51:28

Eh.. I have a question about all this which I'm surpisded no one has asked,
What is the rate of CO2 consumption by 'Oceanis Borealis' ?

that's right, we forgot that, once there is liquid water on Mars, it can pump a lot of CO2, deplete the atmosphere and diminish the green housing effect and the temperature would fall. However that might be good too: Calcacerous algea, or photosynthetic bacteria such as the bacterial symbiont in the corals, could absorb the CO2 and produce a lot of calcium carbonate, but in exchange they would produce serious amount of oxygen. In this scenario, to maintain the temperature, a continuous production of PFC mixture is required.

on a slightly different topic, future terraformers could install a powerfull microwave generator on one of the Mars moon, and direct the waves on the ice rich regions. Yes, microwaving Mars, why not ? Just dont stay under the moon when it's above your head, or you gonna get a headache.

RobertDyck · 2003-11-25 12:01:49

Well... I did make one major simplification to make the calculation managable. I assumed gravity is the same at all altitudes. Actually, a planetary atmosphere is so thick that gravity does measurably decrease with altitude. Then you have to calculate atmospheric gas mass at different altitudes and the weight that is caused by mass*gravity at that altitude. It is actually continuous, so it's a calculus formula. I don't know the formula, and the only atmospheric scientists I know don't appreciate terraforming. Most of the scientists I met at last year's Canadian Space Exploration Workshop snear at the idea of terraforming, so I can't ask them. Assuming gravity is constant isn't too serious a fudge.

Eh.. I have a question about all this which I'm surpisded no one has asked,
What is the rate of CO2 consumption by 'Oceanis Borealis' ?

Unfortunately I have no idea what the CO2 consumption rate is for 'Oceanis Borealis' or any other patch of regolith. I don't think anyone knows. At last year's Workshop I did suggest an orbital Mars probe to measure dry ice mass by using two different synthetic apperature radars, one designed to reflect off the top of CO2 and the other to penetrate and reflect off the ground beneith. If both instruments 'ping' at the same time, you can subtract the altitude of the results to get the thickness of the dry ice. You could also measure return signal strength of the one that penetrated to determine CO2 density. Once you have both density and thickness you can calculate mass. Or would signal attenuation measure mass directly? I would also place on the same Mars satellite an instrument to measure atmospheric density. By measuring density of the atmosphere quickly enough you can detect a CO2 sink releasing or absorbing CO2. If the mass of CO2 released is less than the mass of dry ice sublimated, that would imply another sink in action, a sink such as CO2 absorbed into regolith. I argued that since over 95% of the atmosphere is CO2, measuring CO2 sinks and sources would permit building an accurate weather model for Mars. Predicting Mars weather would be very useful for future Mars missions. However, they said I wanted to terraform Mars (Ok, that?s true) so they dismissed me.

Shaun Barrett · 2003-11-25 18:20:14

Robert, I think it's appalling that so-called scientists clam up and refuse to discuss a hypothetical terraforming problem simply because of their own prejudices. It sounds distinctly like childish petulance to me, unworthy of the scientific endeavour.
I don't happen to agree with the 'Reds' when it comes to Mars colonisation, but I recognise that they think that way for a reason which must make perfect sense to them. Many of the 'Reds' I've come across are evidently highly intelligent people and, therefore, I listen to their logic and try to understand how they think. That's how science has to be, too. The scientists you speak of are a disappointment to me, especially if they're representative of today's scientists in general.
It makes me appreciate Dr. Zubrin all the more.

Some of you will be familiar with my posts concerning Dr. Gil Levin's contribution to the Viking mission, known as the Labeled Release experiment (LR). Almost everybody who bravely took the trouble to plough through my tiresome ranting, must surely be heartily sick of me suggesting, as does Dr Levin of course, that the large volumes of O2 released were due to metabolising micro-organisms!
That still seems like the most logical explanantion, as far as I'm concerned, but that's not my point here.
Let's assume for a moment that both Dr. Levin and myself are barking mad ( Hey! ... I heard that!! ) and that the mainstream view is correct and (a sterile) Mars really is coated in peroxides and exotic superoxides. That oxygen must have been released simply by the addition of water to the regolith.
Let's now imagine our early terraforming efforts, which will consist of raising the average temperature on Mars to create a runaway greenhouse effect and melt all that beautiful water-ice at the poles and in the soil. Not only will adsorbed CO2 be released from the surface material, but it seems likely that vast quantities of O2 will be released simultaneously - perhaps even more O2 than CO2.
In fact, it doesn't seem beyond the realm of possibility that we could get an atmosphere, right from the early days of terraforming, with, say, 200 millibars of CO2 and 200 millibars of O2!
Maybe we're all being way too pessimistic, including me. Maybe we'll get 300 mb of CO2 and 300 mb of O2!! (Must go get my tranquilisers ... ! )

Personally, I think Mars probably has RNA/DNA-based life, because of impact transfer over the eons, but I don't really mind if I'm wrong because then I get all those oxides we've been told about! (Plus, I don't get the ASPCB - 'American Society for the Prevention of Cruelty to Bacteria' - breathing down my neck and opposing terraforming.)

As for the absorption of CO2 from our new Martian atmosphere into the Oceanus Borealis, it could be problematic but I suspect the process will be relatively slow. Even if it happens quite quickly, say over a period of a few thousand years, it may serve to help us in our attempts to 'scrub' most of the CO2 from the air (Att. Byron! ), a necessity if we're ever to breathe on the surface without respirators.
In the meantime, we can tackle the problem of replacing the diminishing CO2 with our 'buffer gas' of choice, nitrogen. Which brings us back to the nitrate deposits and/or the Kuiper Belt ... !

Rxke · 2003-11-26 04:23:59

a bit off-topic...

But the runaway- effect sometimes bothers me.

Imagine, equilibrum point is reached, massive outgassing occurs, ....
Now that would cause localized pressure increases uncomparable to anything seen on earth...
How severe would the storms be? Quite severe, i'd imagine. Initially, not such a problem: low initial atm. pressure: not much energy-transport, (although, today there's the effect of very steep temp gradients, soil temp c/q atmospheric temp... atm. temp drops very fast the initial few meters, unlike on earth, so outgassing would cause 'low elevation' eddies/dustdevils on a bigger scale, pumping increasingly more dust into the atm.(?)

As pressure rises, Mars hurricanes, loaded with increasingly heavier dust-particles, etc could be something to fear... I guess on any given location, they'd start every Mars day, around sunrize (cold-hot-terminator, or whatever the right term is...), circling the planet, (following that 'cold-hot' zone...) till a new equilibrum has been reached.

Or am i a doomsday prophet?

RobertDyck · 2003-11-26 08:48:18

Correcting the math errors from my previous post?

Let's use 2.4656 psi pressure. The figure I quoted before of 2.5 psi is only accurate to 2 significant figures, so this new value is within experimental error. That works out to 170 mb (a nice round figure) or 17,000 Pascals. 1 Pa = 1 N/m^2 and one Newton of force is 1 kilogram of mass accelerated at 1 metre per second squared (1 N = 1 kg?m/s^2). Mars equatorial surface gravity is 3.72 m/s^2. To achieve a pressure of 17,000 Pa on Mars you require 4569.89 kg sitting on each square metre of land. Mars radius is 3,397.2 km so applying the formula area = 4*pi*r^2 we get 145,028,079 square kilometres, or the same number of millions of square metres. That requires 662.76 trillion tonnes of gas. How many tonnes of dry ice are on Mars? Dry ice has a density of 1562 kg/m^3 so it would require 424.3 trillion cubic metres of dry ice, or 424,300 cubic kilometres. If that were spread evenly over the surface of Mars, it would be 2.9 metres deep. I know there is a lot of dry ice on Mars, but that seems a bit much.

Shaun Barrett · 2003-11-26 19:30:28

You raise an important point, Rxke, concerning the transition period from the present conditions on Mars to the kind of terraformed world most of us here (I think! ) want.
As I understand it, much of the violence in the winds on Mars at present stems from the large temperature differentials between the night side and day side of the planet, and between the summer and winter hemispheres. These big temperature differentials, compared to those on Earth, are due to the absence of the moderating influences of a dense atmosphere and large oceans.This violence is currently heavily muted on Mars, of course, by the fact that the air is so tenuous and therefore lacks the power of terrestrial winds.

But, as you rightly point out, there may be a time during terraforming when the air is thicker but there is still no northern ocean and little atmospheric humidity. The temperature differentials may still be routinely greater than on Earth, leading to high winds, but now the winds would have much greater energy-carrying capacity and be more destructive. In addition, they would be able to carry much more dust.
Since nobody has ever attempted deliberately to terraform a planet before, this is all speculation but it does seem possible there'll be a period during the process when conditions on Mars will be considerably worse than they are now. (This was represented in KSR's Mars trilogy as the period when one of the main characters was killed in a massive flow of ice, mud and freezing cold water in Mariner Valley. From memory, the dust storms during this time were a major problem too.)

I think the lesson to be learned from this is that terraforming will be no picnic in the transition stages; definitely not for the faint-hearted! But I believe the transition could be relatively short and that the end result will be very much worth the effort.

Hi Robert! I was pleased to see that my calculations yielded much the same result as yours ... ~425,000 cu. km of solid dry-ice ... despite the slightly different route used to get there.
Your final calculation, showing Mars would need a layer of 2.9 m of solid dry-ice (on average over the whole surface), in order to produce the atmospheric 'bulking-up' required, helps to put the whole thing into perspective.
It sounds like a lot, as you indicated, but there have been serious estimates made that the Martian regolith could conceivably have as much as 800 millibars worth of CO2 adsorbed onto its 'soil' particles. I'm not sure how these estimates were arrived at, and I know not everyone agrees with them, but presumably there must be some mechanism by which such amounts of CO2 could be sequestered in the surface layers of Mars.
All I'm saying is I hope so!

RobertDyck · 2003-11-27 08:19:32

there have been serious estimates made that the Martian regolith could conceivably have as much as 800 millibars worth of CO2 adsorbed onto its 'soil' particles. I'm not sure how these estimates were arrived at, and I know not everyone agrees with them, but presumably there must be some mechanism by which such amounts of CO2 could be sequestered in the surface layers of Mars.

Soil particles could adsorb CO2. That is, CO2 could accumulate on the particle surface. It could only occur where the temperature stays below -78.5?C, the freezing tempertaure of CO2. If the temperature ever got above that, CO2 would sublimate.

Shaun Barrett · 2003-11-27 19:55:55

Robert Dyck:-

It could only occur where the temperature stays below -78.5(deg. C), the freezing temperature of CO2. If the temperature ever got above that, CO2 would sublimate.

This is an interesting point. I don't know exactly how the adsorption of CO2 onto soil particles occurs and neither do I know how the carrying capacity of an individual regolith grain varies with temperature and grain area. But it seems intuitively correct that the higher the temperature, the less CO2 can be adsorbed, although I can imagine it not being an all-or-nothing situation with the sublimation point of CO2 (-78.5 deg. C) being the only factor. I can visualise a scenario wherein CO2 molecules, under pressure at some arbitrary depth in the regolith, might remain adsorbed above their normal sublimation temperature.

I was googling for some information when I came across Lunar And Planetary Science XXIX 1621.pdf Page 2. The title of the section is "Verifying Biological Containment" and actually pertains to how to get a martian soil sample back to Earth in pristine unaltered condition.
The excerpt which is relevant to our discussion here is as follows:-

Several studies of the martian regolith [Fanale and Cannon, 1974,1978,1979; Gooding, 1990; Allton, 1990; Jenkins et al., 1992] indicate that large amounts of volatiles may be adsorbed. Adsorption is strongly dependent on regolith composition and temperature. The models of Gooding[1990] indicate that 1 to 10 atm of adsorbed CO2 could be released upon heating of clay-rich samples from the martian polar regions.

"1 to 10 atm"!! This is a startling figure. I'm not sure whether more recent research has put any new upper limits on the potential amount of CO2 available in the regolith, but it still seems possible that there is a very great deal of CO2 to be had if we simply warm the planet.
Maybe the failure to detect any carbonate rocks so far on Mars is an indication that Mars was never wet long enough to sequester most of the carbon from its atmosphere. (Although other evidence suggests that that's not the case.)
Who knows? Perhaps a very substantial proportion of the original putative 5 to 10 bar CO2 atmosphere is still 'there for the taking' in the soil. (?)

Any thoughts anyone? ???

RobertDyck · 2003-11-28 08:17:19

I like to quote from the paper "A Global View of Martian Surface Compositions from MGS-TES", Joshua L. Bandfield, Victoria E. Hamilton, Philip R. Christensen, Science, 3 March 2000, volume 287, pages 1626-1630. The references for that paper included the URL for a web page that had supplimentary data, which was the two surface types alluded to in the paper itself. They determined two primary surface types with a varying mixture of the two types at any point on Mars surface. I could give the entire tables, but the minerals I would like to point out are:
surface type 1: kaolinite 2.4%, illite 9.9%
surface type 2: Fe-smectite 9.2%, illite 2.2%

These are forms of clay. Clay is formed by hydrological weathering of feldspar, and Mars has a lot of feldspar. With 12.3% to 11.4% clay on the surface, that implies a lot of water over an extended time. In fact, kaolinite is normally formed by moving water such as a river or stream. However, surface type 2 also has 2.9% olivine and no serpentine (a result of weathering olivine), while service type 1 has no olivine and 4.8% serpentine. Both surface types have gypsum, surface type 1 has 1.8% and suface type 2 has 4.5%, while neither has anhydrite. In the presense of water, anhydrite will weather into gypsum very rapidly.

This indicates both surfaces experienced water, but surface type 1 had flowing water across it.

RobertDyck · 2003-11-29 15:02:26

Hmm, no one else has contributed to this thread. Well, there is strong evidence of water on Mars. An estimate of 1 to 10 atmospheres of pressure worth of CO2 sequestered in the regolith? I have no way of commenting on that. I did talk to my chemist friend last night. He mentioned there could have been various carbonates or nitrates formed while liquid water existed on Mars. He also pointed out there are no nitrates or carbonates on the surface of the Sahara dessert, so this demonstrates that dessert-like conditions destroy such compounds. He is not surprised there are no nitrates or carbonates easily detectable by the instruments we have sent so far to probe the surface of Mars, but there may be deposits buried underground. We could speculate about the chemical composition: iron-carbonate, magnesium-carbonate, calcium-carbonate, or exotic organic carbonates such as ethylene-carbonate. Nitrates could similarly have various forms, he couldn't speculate on what was likely given a CO2 rich atmosphere in Mars past. The scientists I talked to at last year's Canadian Space Exploration Workshop said they thought the nitrogen just escaped into space, and any excess CO2 likewise. My chemist friend last night said that any nitrogen that wasn't sequestered would probably have escaped into space. At this point we can only speculate, we really need more data.

I think the orbiter portion of the European Mars Express will measure hydrogen to a greater depth than Odyssey. The two big Mars Exploration Rovers will give us a better description of the geology. Perhaps we should pick-up the terraforming discussion again in a couple months after we start getting results.

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