A Further Example of Theory Development.

In the previous post I discussed some of what is required to form a theory, and I proposed a theory at odds with everyone else as to how the Martian rivers flowed. One advantage of that theory is that provided the conditions hold, it at least explains what it set out to do. However, the real test of a theory is that it then either predicts something, or at least explains something else it was not designed to do.

Currently there is no real theory that explains Martian river flow if you accept the standard assumption that the initial atmosphere was full of carbon dioxide. To explore possible explanations, the obvious next step is to discard that assumption. The concept is that whenever forming theories, you should look at the premises and ask, if not, what?

The reason everyone thinks that the original gases were mainly carbon dioxide appears to be because volcanoes on Earth largely give off carbon dioxide. There can be two reasons for that. The first is that most volcanoes actually reprocess subducted material, which includes carbonates such as lime. The few that do not may be as they are because the crust has used up its ability to turn CO2 into hydrocarbons. That reaction depends on Fe (II) also converting to Fe (III), and it can only do that once. Further, there are many silicates with Fe (II) that cannot do it because the structure is too tightly bound, and the water and CO2 cannot get at the iron atoms. Then, if that did not happen, would methane be detected? Any methane present mixed with the red hot lava would burn on contact with air. Samples are never taken that close to the origin. (As an aside, hydrocarbon have been found, especially where the eruptions are under water.)

Also, on the early planet, iron dust will have accreted, as will other reducing agents, but the point of such agents is, they can also only be used once. What happens now will be very different from what happened then. Finally, according to my theory, the materials were already reduced. In this context we know that there are samples of meteorites that have serious reduced matter, such as phosphides, nitrides and carbides (both of which I argue should have been present), and even silicides.

There is also a practical point. We have one sample of Earth’s sea/ocean from over three billion years ago. There were quite high levels of ammonia in it. Interestingly, when that was found, the information ended up as an aside in a scientific paper. Because it was inexplicable to the authors, it appears they said the least they could.

Now if this seems too much, bear with me, because I am shortly going to get to the point of this. But first, a little chemistry, where I look at the mechanism of making these reduced gases. For simplicity, consider the single bond between a metal M and, say, a nitrogen atom N in a nitride. Call that M – N. Now, let it be attacked by water. (The diagram I tried to include refused to cooperate. Sorry) Anyway, the water attacks the metal and because the number of bonds around the metal stays the same, a hydrogen atom has to get attached to N, thus we get M-OH  + NH. Do this three times and we have ammonia, and three hydroxide groups on a metal ion. Eventually, two hydroxides will convert to one oxide and one molecule of water will be regenerated. The hydroxides do not have to be on the same metal to form water.

Now, the important thing is, only one hydrogen gets transferred per water molecule attack. Now suppose we have one hydrogen atom and one deuterium atom. Now, the one that is preferentially transferred is the one that it is easier to transfer, in which case the deuterium will preferentially stay on the oxygen because the ease of transfer depends on the bond strength. While the strength of a chemical bond starts out depending only on the electromagnetic forces, which will be the same for hydrogen and deuterium, that strength is reduced by the zero point vibrational energy, which is required by quantum mechanics. There is something called the Uncertainty Principle that says that two objects at the quantum level cannot be an exact distance from each other, because then they would have exact position, and exact momentum (zero). Accordingly, the bonds have to vibrate, and the energy of the vibration happens to depend on the mass of the atoms. The bond to hydrogen vibrates the fastest, so less energy is subtracted for deuterium. That means that deuterium is more likely to remain on the regenerated water molecule. This is an example of the chemical isotope effect.

There are other ways of enriching deuterium from water. The one usually considered for planetary bodies is that as water vapour rises, solar winds will blow off some water or UV radiation will break a oxygen – hydrogen bond, and knock the hydroden atom to space. Since deuterium is heavier, it is slightly less likely to get to the top. The problem with this is that the evidence does not back up the solar wind concept (it does happen, but not enough) and if the UV splitting of water is the reason, then there should be an excess of oxygen on the planet. That could work for Earth, but Earth has the least deuterium enrichment of the rocky planets. If it were the way Venus got its huge deuterium enhancement, there had to be a huge ocean initially, and if that is used to explain why there is so much deuterium, then where is the oxygen?

Suppose the deuterium levels in a planet’s hydrogen supply is primarily due to the chemical isotope effect, what would you expect? If the model of atmospheric formation noted in the previous post is correct, the enrichment would depend on the gas to water ratio. The planet with the lowest ratio, i.e. minimal gas/water would have the least enrichment, and vice versa. Earth has the least enrichment. The planet with the highest ratio, i.e. the least water to make gas, would have the greatest enrichment, and here we see that Venus has a huge deuterium enrichment, and very little water (that little is bound up in sulphuric acid in the atmosphere). It is quite comforting when a theory predicts something that was not intended. If this is correct, Venus never had much water on the surface because what it accreted in this hotter zone was used to make the greater atmosphere.

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The Rivers of Mars: How and Why?

My first self-published ebook was about how to form a theory. The origin of this has an interesting history: Elsevier asked me to write a book, and while I know what they thought they were going to get, I sent back a proposal that I thought they could never accept, largely to get them off my back. They accepted it, at that stage, so I had to write. The problem for me was, it took somewhat longer than I expected; the problem for them was the time taken, the length, and then, horrors, they found out I was not an academic with lots of students forced to buy the book. The book was orphaned, but I was so far on I thought I might as well self publish it. The advocated methodology is that of Aristotle, and oddly enough, most of his scientific bloopers arose because he ignored his own instructions! So, let me show what I made of it on one of my projects: how did Mars ever have flowing rivers? Why I chose that is a story best left for a later post.

The first step is to state clearly what you know. In this case, Mars has some quite long what seem like riverbeds, and they start sometimes from the coldest parts of Mars. The longest goes from highlands 60 degrees south and stops somewhere near the equator, and these can only reasonably be explained by fluid flow. Almost certainly water is the only fluid there in sufficient volume, so it had to be at least part of the flow. However, water freezes at 0 degrees Centigrade, the average temperature on Mars now is about minus 60 degrees C, and when the rivers were flowing the sun had only about 2/3 its current heat output.

The next step is to ask questions. To start, how did water flow, starting from high altitude high latitude sites, where the temperatures would be well below that of the rest of the planet? Could we dissolve something in the water to lower the freezing point? Dissolving salts in the water depresses the freezing point, but even the aggressive calcium chloride will not buy you more than forty degrees, so that is not adequate by itself. There are worse problems with this explanation: where did these salts come from, and how could salts get into snow on the southern highlands?

The standard explanation is that there must have been a greenhouse effect, and many have argued for a very significant carbon dioxide atmosphere. There are three problems with this explanation. The first is, it won’t work. Anything less than ten atmospheres pressure is inadequate, and at three atmospheres, the carbon dioxide liquefies. You cannot get sufficient pressure. The second is, the winters on Mars are very long, and carbon dioxide would snow out on the poles, thus reducing the pressure, and because of the albedo of the snow, not all of it would revolatalize, so as the years progressed, the planet would quickly become what it is like now. The third problem is, if there were that much carbon dioxide, where did it go? From isotope fractionation, it appears that about half of the original material that stayed in the atmosphere has been lost to space. Some more could well be frozen out on the poles. However, if there were enough to sustain liquid water for extended periods of time, there should be a lot of carbonates, and there are not. Now it is true we do not know how much could be buried, so maybe that argument is a bit on the weak side. On the other hand, there is plenty of other evidence that the atmosphere of Mars was always thin, although not as thin as now, as there had to be enough to keep water liquid. A number of estimates put it in the 100 millibar range. Further, if it lasted for periods of a few hundred thousand years it could not have been carbon dioxide, at least not initially as otherwise most would have snowed out. Of course it could have been continuously replenished by volcanic action, but if so, there must be very large deposits of carbon dioxide at the poles and that does not appear to be the case. So by asking such simple questions, we have made progress.

The next question is, how did the gases and water get to Mars? This is a rather convoluted question, but the simple answer is, the river flows lasted for only a few hundred thousand years and they started about 1.5 billion years after Mars formed. They also corresponded to significant periods of volcanic eruptions, so the most likely answer for the gases is they came from volcanic eruptions. Most of the water would have too, however it is possible that there were ice deposits near the surface following accretion. The next question is, how did the gases get below the surface of Mars to be erupted?

If we think about them being adsorbed during accretion, then, with the exception of water and ammonia, because the heats of adsorption are very similar for various gases, they would be adsorbed approximately proportional to their concentrations in the disk gases. That would mean, predominantly hydrogen and helium, although these would have been subsequently lost to space. However, neon would also be a very common gas, and to a lesser degree argon, but both neon and argon (apart from argon 40, which is a decay product of potassium 40) are very rare on Mars, so that was not the mechanism.

A commonly quoted mechanism is the volatiles arrived on the rocky planets through comets. That is not valid, at least for Earth, the reason being that the deuterium levels on comets are too high. Another suggestion is they arrived on carbonaceous chondrites. That too does not ring true, first because there would have had to be a huge number more of them, but not silicaceous asteroids, and second, the isotopes of some other elements rule that out. As far as Mars goes, there is the additional point that since it had no plate tectonics, and it had a rocky surface approximately three million years after formation, there is no mechanism to get the gases below the surface.

The only way they could get there is to be accreted as solids. Water would bind chemically to silicates; carbon would probably be accreted as carbides, or as carbon; nitrogen would be accreted as nitrides. The gases are then formed by the reaction of water with the carbides or nitrides, so the amount of gas available depends on how many of these solids were formed, and how much water was accreted. The lower levels of these gases on Mars is due to the fact that the material in the Mars feeding zone never got as hot as around Earth during stellar accretion. The higher temperature in the Venusian accretion zone is why it also has about three times the nitrogen as Earth: nitrides were easier to form at higher temperatures. Water binding to silicates happened after the disk cooled, but before the dust accreted to planets, and Mars has less water because the better aluminosilicates never phase separated because the temperatures earlier were never hot enough. Venus got less water because the disk never got as cool as around Earth and the silicates could not absorb so much.

When water reacts with nitrides and carbides it makes ammonia and methane, and these are most stable under high pressure, which is easily obtained in the interior of planets. If so, this hypothesis predicts that the initial atmosphere would comprise ammonia and methane. This is usually considered to be wrong because ammonia in the atmosphere is quickly decomposed by UV radiation, however, the ammonia will not stay in the atmosphere. Ammonia is rapidly absorbed by water, and even snow, and it will liquefy ice even at minus 80 degrees C. That gets it out of the atmosphere quickly and now there is a simple mechanism why water would flow, and also why it would later stop flowing near the equator and form ice deposits: as it got warmer, the ammonia would evaporate off. The atmosphere would start as methane, but would gradually be oxidised to carbon dioxide, which is why the atmosphere had such a short life. The carbon dioxide would react with ammonia, and eventually the ammonium carbonate would be converted to urea and the water would stop flowing. Thus in this theory under the soil of Mars, provided it has not reacted further, there is just the fertilizer settlers would need.

Where to settle on Mars?

A few weeks ago I wrote an introductory post on Martian settlement issues (https://wordpress.com/post/ianmillerblog.wordpress.com/716 ). I am now going to ask, where should such a settlement be? Obviously, this is a matter of opinion, but there are some facts to consider. The first is seasons. The northern hemisphere spring and summer is about 75 Martian days longer than the autumn and winter (and opposite for the southern hemisphere. This is a consequence of the elliptical orbit, but it also means that the longer seasons mean the planet is further from the sun (which is why it is going slower) and because of the axial tilt that generates the seasons as well as the elliptical orbit, most likely places can get up to 40% less sunlight in winter than in summer. Add to that that by being so much further from the sun, Mars never gets more than about half the Earth’s solar energy. So the southern hemisphere has a shorter but warmer pair of seasons, and a longer colder other pair. Temperatures in summer can get up to 20 degrees C in the day and in winter, fall to minus 120 degrees C during the night. No plant can survive that, so besides providing air, heat is also required.

There is a reasonably easy way to get around the heat problem. Assuming you have a nearby power plant, and as I shall show in other posts, if a settlement is to be viable, it will have a heavy demand for high quality energy, then there will inevitably be waste heat. Space mirrors can also supplement the heat and light. Heating the planet is not on (you would need mirrors of area greater than the Martian cross-sectional area) but heating a settlement is plausible.

The location could be decided on the basis of nearness to raw materials, but that leaves open the question of which ones? The obvious one is metal ores, but here we do not know where they are, of even if they are. Again this can be left for another post.

The next question is air. Air pressure depends on altitude, and much of the exploration so far has been around the zero of altitude, where we get pressures of around 6 -8 millibar, depending on the season. In the southern hemisphere summer, the pole shrinks and vaporizes a lot of carbon dioxide, thus increasing atmospheric pressure. In my novel Red Gold I put the initial settlement at the bottom of Hellas Planitia. That is in the southern hemisphere, and is a giant impact crater, the bottom of which is about nine kilometres deep. That gives more atmospheric pressure, but at the cost of a cold winter. The important point of Hellas Planitia is that at the bottom of the impact crater the pressure, is high enough to be the only place on Mars for liquid water to exist, particularly in summer. The reason this was important, at least in my novel, is that unless you find water, you will probably have to pump it from the atmosphere and condense it. Also, while you are pumping up domes, you will want to get the dust out of the air. The dust is extremely fine. That means very fine filters, which easily clog; electrostatic dust precipitators, which may be too slow for many uses; or a form of water filtration. In Red Gold, I opted for a water-ring type pump. Of course here you need a certain amount of water to get started, and that will not be a small amount. The water will still evaporate fairly quickly, hence the need to have plenty of water, but the evaporite will go into the dome, so it is recoverable or usable. It could also be frozen out before going in; whatever else is in short supply on Mars, cold is not one of them, although with the low atmospheric pressure, the heat capacity of air is fairly low.

So strictly speaking, based on heat and air, both have to be heavily supplemented, it does not matter where you go. However, I think there is another good reason for selecting Hellas Planitia as the site. It is generally considered that water, or at least a fluid, flowed on Mars. The lower parts of Hellas have signs that there was water there once, and to the east two great channels, the Dao and the Harmarkis, seemingly emptied themselves into the Hellas basin. Water will flow downhill, so a lot of it would have resided in depressions, and either evaporated, or solidified, or both. So, there is a good chance that there is water there, or anything that got dissolved in the water. The higher air pressure will also help reduce sublimation by a little bit, so perhaps there will be more there than most places.

The next issue is, you wish to grow food and have plants make oxygen. Obviously you will need some fairly sophisticated equipment to get the oxygen from the plants to wherever you are going to live, assuming you don’t live with the plants, but the plants have to grow first. For that you need soil, water and fertilizer. The soil is the first problem. It is highly oxidised, and chlorides have been oxidised to perchlorates. That is fine for making a little oxygen, but it has to be treated or it will kill plants. Apparently it is something as good as bleaching powder. Again, you will have to take the treatment chemicals with you; forget something critical or do not bring enough, and you will be dead. Mars is not a forgiving place.

That leaves fertilizer. Most rock has some potassium and phosphate in it, and if these have been washed out, their residues will be where the water ended, so that should be no problem if you go to the right place. Nitrogen is slightly different. The atmosphere has very little nitrogen. On Earth, plants get their nitrogen from nitrates washed down in rain, from decayed biomass, and from farmers applying it. None of that works there immediately. Legumes can “fix” nitrogen from the air, but there isn’t much there to fix and partial pressure is important. You can, of course, pump it up and get rid of carbon dioxide. A lot of these issues were in the background of my ebook novel Red Gold, ad there, I proposed that Mars originally had somewhat more nitrogen, but it ended up underground. The reason is for another post, but the reason I had then ended up as being the start of my theory regarding planetary formation. However, the possibility of what was leached out or condensed out being at the bottom of the crater is why I think Hellas Planitia is as good a place as any to start a settlement.

Quick Commercial: Red Gold will be discounted to 99 c for six days starting the 13th. It is basically about fraud, late 1980s style, but much of the details of settling Mars are there.

Liquid Fuels from Algae

In the previous post, I discussed biofuels in general. Now I shall get more specific, with one particular source that I have worked on. That is attempting to make liquid fuels from macro and microalgae. I was recently sent the following link:

https://www.fool.com/investing/2017/06/25/exxonmobil-to-climate-change-activists-chew-on-thi.aspx

In this, it was reported that ExxonMobil partnering Synthetic Genomics Inc. have a $600 million collaboration to develop biofuels from microalgae. I think this was sent to make me green with envy, because I was steering the research efforts of a company in New Zealand trying to do the same, except that they had only about $4 million. I rather fancy we had found the way to go with this, albeit with a lot more work to do, but the company foundered when it had to refinance. It could have done this in June 2008, but it put it off until 2009. I think it was in August that Lehmans did a nosedive, and the financial genii of Wall Street managed to find the optimal way to dislocate the world economies without themselves going to jail or, for that matter, becoming poor; it was the lesser souls that paid the price.

The background: microalgae are unique among plants in that they devote most of their photochemical energy into either making protein and lipids, which in more common language are oily fats. If for some reason, such as a shortage of nitrogen, they will swell up and just make lipids, and about 75 – 80% of their mass are comprised of these, and when nitrogen starved, they can reach about 70% lipids before they die of starvation. When nitrogen is plentiful, they try to reproduce as fast as they can, and that is rapid. Algae are the fastest growing plants on the planet. One problem with microalgae: they are very small, and hence difficult to harvest.

So what is ExxonMobil doing? According to this article they have trawled the world looking for samples of microalgae that give high yields of oil. They have tried gene-editing techniques to grow a strain that will double oil production without affecting growth rate, and they grow these in special tubes. To be relevant, they need a lot of tubes. According to the article, if they try open tanks, they need an area about the size of Colorado to supply America’s oil demand, and a corresponding lot of water. So, what is wrong here? In my opinion, just about everything.

First, you want to increase the oil yield? Take the microalgae from the rapidly growing stage and grow them in nitrogen-starved conditions. No need for special genetics. Second, if you are going to grow your microalgae in open tanks (to let in the necessary carbon dioxide and reduce containment costs) you also let in airborne algae. Eventually, they will take over because evolution has made them more competitive than your engineered strain. Third, no need to consider producing all of America’s liquid fuels all at once; electricity will take up some, and in any case, there is no single fix. We need what we can get. Fourth, if you want area, where is the greatest area with sufficient water? Anyone vote for the ocean? It is also possible that microalgae may not be the only option, because if you use the sea, you could try macroalgae, some of which such as Macrocystis pyrifera grow almost as fast, although they do not make significant levels of lipids.

We do not know how ExxonMobil intended to process their algae. What many people advocate is to extract out the lipids and convert them to biodiesel by reacting them with something like sodium methoxide. To stop horrible emulsions while extracting, the microalgae need to be dried, and that uses energy. My approach was to use simple high pressure processing in water, hence no need to dry the algae, from which both a high-octane petrol fraction and a high-cetane diesel fraction could be obtained. Conversion efficiencies are good, but there are many other byproducts, and some of the residue is very tarry.

After asking where the best supply of microalgae could be found, we came up with sewage treatment ponds. No capital requirement for building the ponds, and the microalgae are already there. In the nutrient rich water, they grow like mad, and take up the nutrients that would otherwise be considered pollutants like sponges. The lipid level by simple extraction is depressingly low, but the levels that are bound elsewhere in the algae are higher. There is then the question of costs. The big cost is in harvesting the microalgae, which is why macroalgae would be a better bet in the oceans.

The value of the high pressure processing (an accelerated treatment that mimics how nature made our crude oil in the first place) is now apparent: while the bulk of the material is not necessarily a fuel, the value of the “byproducts” of your fuel process vastly exceeds the value of the fuel. It is far easier to make money while still working on the smaller scale. (The chemical industry is very scale dependent. The cost of making something is such that if you construct a similar processing plant that doubles production, the unit cost of the larger plant is about 60% that of the smaller plant.)

So the approach I favour involves taking mainly algal biomass, including some microalgae from the ocean (and containing that might be a problem) and aiming initially to make most of your money from the chemical outputs. One of the ones I like a lot is a suite of compounds with low antibacterial activity, which should be good for feeding chickens and such, which in turn would remove the breeding ground for antibiotic resistant superbugs. There are plenty of opportunities, but unfortunately, a lot of effort and money required it make it work.

For more information on biofuels, my ebook, Biofuels An Overview is available at Smashwords through July for $0.99. Coupon code NY22C