New Mars Forums

Hmmm.
    Yeah, I think that would have made me nervous!
                                                 :

Just a small point, but Earth is known as the blue planet. How would it look with everything as it is but the background green and Earth blue (leaving Mars red, of course)?
    Incidentally, how do people feel about making either Mars smaller or Earth bigger, to better represent their actual relative proportions? Or is this an unnecessary adherence to reality which would ruin the artistic cohesion of the design?

    No canoe to paddle here! I'm just chewin' the rug.
                                                     

Robert Dyck:-

    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:-

    "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?          ???   

Thanks, Rxke.
    I empathised particularly with the frustrated resignation in one of his responses: " ... issues that were more or less resolved and should have been settled in the 1700s. (Sigh)"
    What pathetic creatures some of us humans can be.

    What an interesting old man. I would very much like to spend a few hours with him ... if he could stand it!

Hi Jadeheart!
    For all I know, your gold-plated mountains on Venus could be a reality. However, a quick google shows gold's melting point as 1064 deg.C, while lead melts at 327 deg.C.
    The ambient temperature on Venus is about 460 deg.C. easily hot enough to liquify lead and give rise to lead vapour, but it seems harder to visualise gold vapour being produced under those conditions.

    However, for the sake of your grand vision of golden peaks, I hope I'm completely wrong!
                                           

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 ... !
                                                 

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:  ]

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!!
                                                 

Yeah!
    At the very least, it's a more detailed and comprehensive space policy (and social policy) than anyone else has right now!
                                           

Rxke:-

    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.
                                             

Hi Rxke!
    As far as I know, super-greenhouse gases would be a faster way to terraform, though terrestrial plants would certainly be part of any long-term efforts.
    The gases used would be tailor-made for the job and would specifically exclude halofluorocarbons, such as chlorofluorocarbon, which 'eat' ozone.

    I know there are people who think Robert Zubrin is crazy but he's actually extremely intelligent and, I believe, psychologically stable!
                                             :laugh:

    You can be quite sure he's aware of pitfalls like ozone depletion by inappropriate use of chemicals, as indeed are all the serious terraformers whose work I've read, and that he's thought the process through in detail.
    For a particularly informative treatment of the subject of terraforming, with only a minimum of technical jargon, read Zubrin and Wagner's "The Case for Mars".
                                               

I assume Robert means raising the ambient pressure on Mars to somewhere between 350 and 500 millibars, and mostly CO2 at that (?). But I may be misinterpreting his meaning.
    It may be possible to produce a breathable atmosphere eventually, by various means, but its hard to see how that could be achieved in only one century. On the other hand, Arthur C. Clarke is fond of pointing out that most of the failures of prediction which have been documented over the last century or so have arisen because of underestimation of the potential of technology, not the opposite. My favourite analogy is to look at heavier-than-air flight at the beginning of the twentieth century. In 1902, heavier-than-air flight was a futuristic concept, and the Wright brothers achievement a year later was still not universally accepted as reality for some years after it occurred. Yet, by 1914, aerial warfare had begun and, by 1927, commercial passenger flights were up and running.
    So, maybe I'm completely underestimating the ability of future 21st century engineering to rebuild the Martian atmosphere in breathable form. Maybe Robert, quite sensibly, is erring on the side of optimism. I'm not sure. 

    Almost any degree of terraforming must inevitably result in the disappearance of CO2 ice from the Martian poles. Even a relatively modest rise in average temperatures would cause this to happen and, as Byron points out, it may be happening as we speak, without any intervention on our part!
    For the record, I am strongly against the use of nuclear bombs to kick-start any terraforming of Mars and I believe such methods are not only repugnant but in all likelihood completely unnecessary. The point Byron raised, about the current remarkably swift sublimation of CO2 layers at the south pole, bolsters my belief that Mars is probably on a 'hair-trigger' as far as climate change is concerned. It seems likely, at least to me, that quite gentle nudges in the direction of greater warmth will bring about a positive feedback mechanism and automatically change the climate in our favour. (However, I admit this is more hunch than confident prediction.)

    I'm still a bit wary of steering massive Kuiper Belt objects into the inner solar system at high velocities. Today, we're hearing more and more about potentially redirecting incoming asteroids in order to avoid having humanity go the way of the dinosaurs. But we're warned, at the same time, that the greatest danger stems from the sudden appearance of previously unknown long-period comets. These bodies travel at maybe 60 km/s and give us little lead-time to change their direction and need greater delta-v values to do so.
    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!!
    Then again, perhaps I'm falling into the same trap I described above, by underestimating the power of future technology. And, in the absence of sufficient nitrogen on Mars, there may be no alternative to 'snowball snooker'!   
    But we'd better get it right!

    As much as we argue about how to go about terraforming, I think it still comes back to super-greenhouse-gas production, as Dr. Zubrin advocates. The effect of even microbar levels of these gases is phenomenal, especially when used in conjunction with, say, a 400 millibar CO2 atmosphere.
    Combined with the use of a large soletta directing extra sunlight to the northern polar regions, where a new Oceanus Borealis may form, Dr. Bob's greenhouse gases will probably give us first-stage terraforming in less than a century anyhow.