New Mars Forums

Quote from MB, re. the theoretical work of Fogg, Sagan, Zubrin and McKay on the topic of terraforming:-
    "These people are making money off the idea that Mars can be terraformed, so they're not about to prove themselves, or allow themselves to be proved, wrong. They've captured the public's desire to colonise other worlds and the romantic fantasy of exploring space and turned it into a commercial product. ... these people are making big bucks by saying "Mars can be Terraformed".
    ... If they had bothered to check, or even do, the figures they would have realised that Hydrogen escape will be an issue, even if only for the amateurs that followed them. They would have highlighted the issue or left it unresolved. But they can't make money from uncertainty so they ignore it, or deflect attention with a "cold trap". If you try to discuss the issue with them and they get aggressive then you know, they know, they're wrong. I have, so I know."

    This is the first time I've ever come across a conspiracy theory accusation aimed at the big names in terraforming!
    Do you seriously propose that Drs, Sagan, Zubrin, and McKay, not to mention Fogg, are prepared to put their names to a lot of hot air about terraforming, risking their hard-earned intellectual reputations, just to sell a few books to a few wild-eyed, ignorant, uncritical space cadets?!
    Do you come here on some kind of a mission to lead us out of the darkness into the light of reason, to sweep away the lies and crass commercialism of the evil Dr. Zubrin and his cronies? Are you suggesting that all of us here are so stupid and easily-led that we are incapable of deciding for ourselves whether or not we're being fed a lot of bulls***?!
                                             ???
    If so, I could imagine more than a few of us feeling somewhat put out by such behaviour.

    Moving on to some other points.
    MB, you ask me about my qualifications. Suffice it to say, they are the equal of your own.
    But the reason I asked about your qualifications was not so you and I could compare the size of our certificates(! ), but rather so we could gauge your fitness to disregard the work of eminent Doctors of Philosophy and come among us to lead us away from our 'fantasies' and toward scientific redemption.

Quote from MB:-
    "What equation did you use to calculate the exospheric temperature? or did you use someone elses estimate?"

    I trawled Google for information on this because I see no reason to re-invent the wheel at every step of the way. No doubt you will find this unsatisfactory.
    The full extent of the exosphere is debatable. There is general agreement that it extends to at least 800km, though some place the ceiling at 1280km. In a constantly thinning medium, it is difficult to be exact. (Apparently, it's possible to theorise that the exosphere extends to an altitude of tens of thousands of kilometres! )
    But there is much closer agreement on the kinds of temperatures found in the thermosphere/exosphere. At an altitude of some 700km, temperatures of up to 2273K occur, while higher up on the sunlit side of the planet temperatures can reach 2773K.
    For the sake of my calculations of helium atom speeds in this region of the atmosphere, I chose the round figure of 2000K in order to be generous to your side of the argument and avoid accusations of choosing figures which suited my own purposes.

Quote from MB re. the figure I used for Earth's escape velocity in my previous post:-
    "Did you include the exobase height in that calculation?"

    First of all, there was no calculation involved. I used the escape velocity quoted in all the texts, which relates to the velocity required at sea-level to completely escape Earth's gravitational field.
    Naturally, at 800km altitude, the escape velocity will be somewhat diminished. If you wish to be pedantic about it, we can do the figures and see what happens. But you understand they will hurt your case, not help it?
    Escape velocity is given by the equation:-
  V.esc = Sq. Rt of (2GM/R)
         Where G is the Gravitational Constant
                   M is the mass of the body
                   R is distance to body's centre of mass
G is 6.673*10^-11 (for SI units)
M is 6*10^24kg (for Earth)
R is 7,178,000m (for an altitude of 800km above sea-level)
    Inserting the numbers into the equation, we find the escape velocity in the exosphere is 10,562m/s

    If we use this escape velocity to find the ratio of V.esc/ V.av, we obtain 10562/2880 = 3.67
    This indicates that helium will be lost from Earth's upper atmosphere faster than the previous calculation indicated!

    Given that there is no doubt Earth cannot retain helium, it certainly cannot retain hydrogen, which is lighter and therefore faster.
    Yet, with more than twice the insolation of Mars, and a correspondingly hotter exosphere, Earth has maintained enormous oceans on its surface for eons.

    You state quite categorically that only planets or Moons with sufficient gravity to retain hydrogen can have water at their surfaces. You have made a list of the bodies which can or cannot be terraformed, based on this tenet.
    Given that you have now had demonstrated to you, again (and with equations), the fact that Earth cannot retain hydrogen and yet has oceans, are you prepared to reconsider your position?
    I think I probably would, if I were you.

Another comment or two.

    MB, May 31 2004, 03:52, wrote the following:-

    Although it has a ">" in front of it, as though it's a quote from someone else's post, I can't find it anywhere else so I assume MB wrote it himself. In any case, it is simply not true that perfluorocarbons are dangerous to humans.

    The following is taken from the Proceedings of the Postgraduate Course on Mechanical Ventilation, Dept. of Anaesthesiology and Intensive Care Medicine, Technical University of Dresden, Germany. The extract comes from a section entitled "Perfluorocarbon aided gas exchange":-

    MB, I don't know where you got the impression that PFCs are somehow poisonous. They are in fact so safe they are deliberately introduced into the human body by doctors in the treatment of certain conditions - especially in cases of severe lung damage.

    PFCs are of particular interest to those of us here who wish to terraform Mars because of their potential as supergreenhouse gases and would be very useful in raising the average temperature of the martian environment.
    It seems odd that you would attack the use of PFCs so strongly when you evidently have so little knowledge of their nature.
                                      ???

    As I mentioned in a previous post, it seems there's little to be gained in re-inventing the wheel as far as Earth's inability to retain light gases is concerned but, by way of clarifying the situation concerning helium, I'll make some comments.
    The kinetic temperature of a gas is proportional to the square of the average particle speed and also proportional to the particle mass.
    This has been expressed in the equation:-
  V = Sq. Rt. of (2*k*T/M)
         Where k is Boltzmann's Constant (1.38066*10^-23)
                  T is the temperature of the atmosphere
                  M is the mass of the particle (atom, molecule etc.)

    The temperature of the atmosphere, for our purposes, applies to the upper atmosphere, specifically the upper reaches of the thermosphere, where atoms and molecules may escape Earth's gravity. On the sunlit side of Earth, the kinetic temperature of the thin atmospheric gases ranges up to 2500 deg.C, or 2773K on the absolute scale. Generally, temperatures are commonly about 2000K.
    6*10^23 helium atoms mass 4 grams ( the gram atomic weight of helium). Therefore one helium atom masses 6.6445*10^-27 kg.
    Inserting the values quoted into the above equation, we find that the average speed of a helium atom at the top of the atmosphere is 2880 m/s
    Earth's escape velocity is 11200 m/s.
    So, does this mean MB is correct? Does Earth really have enough gravity to retain helium? Let's see.

    It's been found that in a gas at a certain temperature, the majority of particles (atoms or molecules) will have a speed, at any given moment, commensurate with that average temperature. But not all of the particles are found to be moving at the same speed. Due to random collisions, some of which slow the particles and others of which speed them up, there is a surprisingly large range of particle speds. Some particles may be almost stationary at a given moment, while others can be moving several times the average speed! (Though, naturally, we find less and less particles at the high end of the speed scale.)
    The spread of the speeds and the numbers of particles moving at those speeds, at any given moment, is described mathematically by a curve called the Maxwell-Boltzmann Distribution.

    Getting back to our helium atoms in Earth's upper atmosphere, although we found their average speed to be about 2880 m/s, the Maxwell-Boltzmann Distribution curve tells us that significant numbers of helium atoms will be moving at speeds several times that figure - speeds in fact higher than the escape velocity of 11200 m/s!
    How does this affect the overall rate of escape of a gas like helium from Earth's gravitational field?
    It has been calculated that the ratio of escape velocity to average particle velocity (V.esc/V.av) can be used to estimate how long a gas can be retained by a planet.
    Here's a table of figures to illustrate the relationship:-

  RATIO            TIME TAKEN FOR ALL THE GAS TO ESCAPE
    7                        Over 1 trillion years
    6                        Over 10 billion years
    5                        About 100 million years
    4                        Under 1 million years
    3                        Under 1 thousand years

    Earth's escape velocity is 11200 m/s and the speed of our average helium atom at the top of the atmosphere is 2880 m/s.
    The ratio, V.esc/V.av, in this case is 11200/2880 = 3.9
    From this we can see that Earth will normally lose all its helium in less than 1 million years - a geologically insignificant period of time.

    Hydrogen is lighter than helium and will therefore be lost even quicker.

    A quote from MB's website, in the sectio headed "Photodissociation and Surface Water":-

    This statement seems very hard to sustain when you consider that Earth very definitely cannot retain hydrogen in its upper atmosphere (see above) and yet has had vast oceans for nearly all of its 4.6 billion year history.

    In fairness, I should say that other calculations do show that Earth has indeed lost about 1 metre of its oceans in that 4.6 billion years. I suppose that means that Earth too will require iceteroids to top up its oceans in about 13.8 trillion years! Does this mean that Earth itself can never be truly terraformed, since it cannot maintain its water indefinitely without 'occasional' outside assistance?
                                                         :;):

Hmmm ... yes.
    I have to admit it's been quite a while since "three handsome women" came to "visit" me. It would probably tend to take one's mind off the study of heavenly bodies ... I suppose?
                        :;):   :laugh:

I don't understand what you're trying to say, MB.
    Reading some of the stuff in your website, it appears you're telling us that Earth only has water at its surface because its gravitational acceleration is sufficient to retain hydrogen in the atmosphere. You go on to say that Mars has insufficient gravity to retain hydrogen and therefore can never have surface water. Therefore, terraforming Mars is impossible.
    I have a problem with your assessment.
    Firstly, Earth can't even retain helium-4 with its gravitational field, never mind lighter H2 molecules. (Trace quantities of helium in Earth's atmosphere come from radioactive decay processes in our planet's crust and mantle, which produce alpha-particle radiation - an alpha-particle simply being a helium nucleus. All Earth's primeval supply of helium was lost to space long ago.) Experiments have indicated that Earth is indeed losing hydrogen as water molecules at high altitudes are dissociated by UV light. But the point is that the process is slow. If present rates of hydrogen loss are typical of losses over Earth's 4.6 billion year history, then we've lost the equivalent of just 1 metre of water from our oceans in all that time!
    My point is that Earth is hardly any better at retaining hydrogen than Mars is, if gravity is the only criterion.

    Admittedly, Mars has disadvantages in retaining volatiles when you compare it with Earth. The martian gravitational field is indeed only 38% the strength of Earth's, so loss rates of many gases must necessarily be faster. In addition, Mars lacks an ozone layer, which means the UV flux is higher throughout the atmosphere - even down to ground level. This must in turn result in higher rates of dissociation of water molecules and consequently higher rates of hydrogen loss. The above problems are exacerbated by the lack of a global magnetic field, leaving most of the upper atmosphere unprotected from volatile losses due to 'sputtering' by the solar wind. (One advantage Mars has, though, is its lower insolation due to its greater distance from the Sun. The resultant overall lower temperatures tend to slow gas molecules and thus make them easier for Mars to retain.)
    The disadvantages I've mentioned may rightly be cited as impediments to the permanent long-term terraforming of Mars, but implying that Mars can never be like Earth because Earth can hold on to hydrogen, while Mars can't, is simply not true. Earth cannot retain any significant quantity of hydrogen for any significant length of time either!

    The problems for Mars and its volatiles, which I've touched on above, nevertheless remain. And it's true to say that if we create an atmosphere and an Oceanus Borealis on the Red Planet, and if efforts are not undertaken to maintain them, the atmosphere will escape and the water will be frozen again into the crust.
    But the process will be very slow, by human standards. Calculations have shown that a dense atmosphere on Mars would take on the order of 10 million Earth-years to leak away.
    For a species only 200,000 years old, 10 million years is a very generous time interval. By the time our terraformed Mars is showing signs of reverting to its former freeze-dried self, we humans will be either extinct or will be possessed of almost God-like technology. In either event, we won't care about volatiles escaping from Mars!

    I have to say, MB, I don't agree with your analysis of the situation at all. Terraforming Mars is not only possible; I believe it will be done.
                                                 

Yes, Cindy, I have no doubt that unscrupulous doctors exist. They come from the same gene pool as the rest of us flawed creatures, so there's no reason to think they're all squeaky-clean! A certain percentage of humanity will do almost anything for a dollar, so why shouldn't a similar percentage of MDs be in the same boat? An unpleasant thought, but probably realistic.   
    [On a more optimistic note, perhaps there is a slightly lesser percentage of crooks among MDs if you subscribe to the idea that at least some people still enter medicine for altruistic reasons rather than for money(?).  ???  ]

    You make a very good point, Mad Grad, about weighing up the risks and at least eliminating the most damaging activities in your life. I do agree with you that smoking is a disproportionately large risk when you consider the 'benefits' - the relaxation aspect and the gratification of a relatively benign addiction. (I say benign because it's not the nicotine that kills you; it's the delivery system! ) But obviously, the benefits and pleasure one gains from driving a car are very much greater, which makes the risk worth it.
    That's why I stopped smoking 18 years ago but still drive a car, even though getting into my car and heading off into traffic is probably an individually more dangerous act than lighting up one cigarette instead. You're quite right that it's all a matter of 'playing the odds'.

    But I happen to believe strongly that the human mind has a powerful and profound influence on the body. This is borne out by research which shows that a happy person's immune system functions far better than that of a depressed person. I believe you can bring on cancer, and other ailments, in your own body simply by being unhappy or overstressed. And I don't think this is totally unsubstantiated 'voodoo medicine' either; holistic medicine has been based on this premise for centuries and it seems to make sense, at least to me.
    Getting back to the man Cindy mentioned, who was diagnosed with a tobacco use disorder, I think my grandmother's simplistic summary of holistic medicine is very apt in this case. A pivotal and very pleasurable part of that man's life, involves a cigarette in the morning with coffee and another at the end of his working day. The regularity and predictability of those two little islands of peace and tranquillity in his workaday world give him great pleasure and satisfaction and, importantly, something to look forward to! And I'd be inclined to think they do him vastly more good than harm because they promote a feeling of well-being, which boosts his immune system and thus his general health. 'A little of what you fancy does you good'!

    Just as an aside, I know we're all wound up in our own health and happiness and worried half to death about trying to live a few years longer. (Spot the paradox! ) But I can remember a different time, when I was a child, when people still smoked pipes. I remember spending vacation time at my grandparents home in Worthing on the south coast of England when I was about 11 years old, and being sent to the corner store for a few groceries and 2 ounces of 'Condor' pipe tobacco. The tobacco was in small, compressed, solid blocks and my grandfather had to break it up and rub it between his fingers, which gave it the shredded consistency necessary for smoking. Those small blocks of tobacco would, when shredded, fill his tobacco pouch and keep him happy for days! The raw tobacco smelled great as I'd watch him tamping a pinch of it into his old wooden pipe. And, as he lit it and puffed repeatedly to get it burning properly, I remember him wreathed in richly aromatic, sweet-smelling smoke.
    The above scene is about as politically incorrect as you're ever likely to witness: smoking is regarded as bad enough on its own but to subject a child to second-hand smoke is looked upon as unforgivable. But I loved it and such scenes form some of the happiest memories of my childhood!
    Smoking that old pipe brought my white-haired grandfather such pleasure that I can't, in my mind, separate the images of him smoking it from the images of him smiling and laughing. Glorious pictures in my head of such a happy gentle man!
    Did the pipe do him any harm? Much less than it did him good, if you ask me. He died when he was 84.

Spoilsport.

Yes, Rex.
    All good points, which I understand form part of your hypothesis about standing bodies of water on Mars today.
    Some of the close-ups of surface features taken by Opportunity do no harm to your ideas at all; in fact, they lend considerable credence to them in my opinion. It appears from the Opportunity photos that a water table ('brine table') could possibly be surprisingly close to the surface in some areas. And this, in turn, fits nicely with the data returned by Odyssey, which indicated varying amounts of water in the top 1 metre of martian soil - as much as 50% in some places (though generally less in equatorial regions, I admit).

    It's definitely fine food for thought and I wouldn't be at all surprised if at least transient bodies of briny water on the martian surface are confirmed in the near future.
                                                   

[And, for the record, I think the methane discovered in the martian air will confirm the existence of bacteria on Mars in the not-too-distant future, too.]

Oh boy, looks like I've really been sleeping on the job lately!   :sleep:   

    For the second year running, I've managed to overlook Cindy's birthday, on the 18th of this month!
    I think I neglected to wish Rik a happy birthday a while back, too!
    I ignored Rex's big day on the 26th of March!
    Then I forgot C M Edwards on the 1st of April!
    And I sailed blithely through the 25th of May without giving Earthfirst's birthday a single thought!

    To all those I've slighted in this careless manner, I offer my apologies and the excuse that I've had a few things on my mind recently.
    Oh .. and I also offer this:-

A VERY HAPPY, THOUGH BELATED, BIRTHDAY!!!
             AND MANY HAPPY RETURNS OF THE DAY!!
                                                     :band:   

Interesting input, Cindy.
    Thanks for the information.
    There are certainly some very sick puppies out there!
                                             

Hi Bolbuyk!
    I believe your doubts about impact transfer of material between Earth and Mars must surely have been laid to rest by the answers provided here.

    In response to your question about Polycyclic Aromatic Hydrocarbons (PAHs) found in ALH 84001, and other points you raise:-

1) The Gas Chromatograph Mass Spectrometer used on the Viking missions has been found to be too insensitive even to detect breeding colonies of bacteria in Antartic soils! Its results on Mars must therefore be discounted.

2) If the PAHs found inside ALH84001 were the result of terrestrial contamination, chemicals seeping in from outside while sitting on the Antarctic ice, one would expect to find a negative concentration gradient as one analysed material deeper into the meteorite, i.e. a higher concentration of PAHs on the outside and lower concentrations towards the centre.
   On the contrary, the PAHs are more concentrated in the interior, which indicates they were in the rock before it left Mars.

3) The small size of the purported bacteria in ALH84001 has been a show-stopper for many researchers, who argue, as you do, that the volume of these structures is simply too small to contain even the most basic of the molecular mechanisms essential to life.
   A controversial hypothesis involving so-called nanobacteria has been used as a counter-argument that life can in fact exist at very small scales; scales hitherto dismissed as impossible. It remains to be seen whether this hypothesis ever becomes mainstream.
   However, the nanobacteria hypothesis mightn't be necessary to explain the 'micro-fossils' in ALH84001. It has been found that bacteria subjected to extreme privation tend to shrink and shrivel as they sink towards death. There could surely be many possible scenarios in which the ALH84001 bacteria, if indeed they were bacteria, suffered a lack of nutrition and/or water before they died. If so, one would expect their remains to be much smaller than a living bacterium.

4) One more piece of evidence in favour of the micro-fossil hypothesis is the existence of the tiny perfectly-formed magnetite crystals found in association with the 'bacterial' remains. As you know, these are typical of crystals found in terrestrial magnetotactic bacteria, which use the magnetite to orientate themselves in dark murky water.
   I think this is a particularly compelling piece of additional evidence that we may indeed be dealing with the remains of martian bacteria in the Allan Hills meteorite.
   (You may want to have a look at http://science.nasa.gov/headlines/y2000 … 1.htm]this site, which gives a neat summary of the magnetite evidence. Be sure to click on 'side-

I agree with Reb.
    I'm looking at my Mars globe right now and the whole area in question, northward along Echus Chasma and into Kasei Vallis heading east, looks smeared like the effect of the incoming tide on a sandcastle at the beach.
    It's inconceivable that anything but large amounts of water could have caused all of this - particularly given the evidence for alluvial deposition cited by Reb.

    Further compelling evidence for fluvial erosion can be found, amongst other places, at the eastern end of Mariner Valley. There, vast areas of Margaritifer and Arabia Terrae (including Meridiani Planum, where Opportunity landed) have been identified as being formerly a part of the cratered 'southern' highlands. However, these regions are now much lower, and the craters heavily eroded, because approximately 1 whole vertical kilometre of the topography has been removed by erosion across thousands of square kilometres of the surface!
    Scientists examining this phenomenal example of massive resurfacing have expressed the opinion that it's difficult to imagine anything but water (and plenty of it! ) being the agent responsible.
    In light of this, Opportunity's confirmation that Meridiani Planum was once awash with water was probably no more than we might have expected.

Hi people!
    I've been otherwise occupied and haven't had a chance to keep up with events here at New Mars lately. There's so much going on in various threads, it's difficult to catch up after being away a while!
    Thanks to everyone who's put the 'pick-of-the-pictures' from Mars here for all to see - it certainly helps those of us scrambling to keep up.   

    By way of trying to 'do my bit', in return, I discovered http://www.space.com/imageoftheday/imag … .html]THIS IMAGE.
    It gives a neat '3-D' overview of what they hope to achieve with Spirit over the next few weeks and more. And it helps to visualise the layout of the Columbia Hills and where the sites of interest lie.