Asteroid Mining

One thing you see often in the media is the concept that perhaps in the future we can solve our resources problem by mining asteroids. Hopefully, that is fine for science fiction, and I use that word “hopefully” because my next piece of science fiction, currently in the editing mode, includes collecting asteroids for minerals extraction. However, what is the reality?

We know we have a resource problem. An unfortunately large and growing number of elements are becoming scarcer and harder to obtain. As a consequence, ores are getting less concentrated, and so much material has to be thrown away. As an example, the earliest use of copper at around 7,000 BC used native copper. All the people had to do was take a piece and hammer it into some desirable shape. Some time later someone found that if something like malachite was accidentally in a fireplace, it got reduced to copper, and metallurgy was founded. Malachite is 57.7% copper, while if you were lucky enough to find cuprite you got a yield of almost 89% copper. Now the average yield of copper from a copper ore is 0.6% and falling. The rest is usually useless silicates. So, you may think, if we have worked through all the easily available stuff here, nobody has worked through the asteroids. There we could get “the good stuff”.

At this point it is worth contemplating what an ore is and where it came from? All the elements heavier than lithium were made in supernovae or through collisions of neutron stars. Either way, if we think of the supernova, the elements are made at an extremely high temperature, and they are flying away from the stellar core at a very high velocity. The net result is they end up as particles that make the particles in smoke look big. This “smoke” gets mixed in with gas clouds that end up making stars and planets. To get some perspective on concentrations, for every million silicon atoms you will get, on average, about 900,000 iron atoms, almost 24,000,000 oxygen atoms, 5420 chlorine atoms, 52,700 sodium atoms, 522 copper atoms, almost half a silver atom, 0.187 gold atoms, 1.34 platinum atoms and about 0.009 uranium atoms.

So what happens depends on whether the elements react in the accretion disk, so that molecules form. For example, all the sodium atoms will either form a chloride or a hydroxide, but the gold atoms will by and large not react. About half the iron atoms form an oxide or stay as the element, and the oxides will end up as silicates (basalt). What happens next depends on how the objects accrete. That is not agreed. Most scientists say they simply don’t know. I believe the bodies are accreted through chemistry. If the former, we have to assume the elements end up as a mix that have those elements in proportion, except for those that make gases. If the latter, then some will be more concentrated than others.

On earth, elements are concentrated into ores by geochemistry. The heat and water processes some elements, and heat and volcanism concentrates others. Thus gold is concentrated by it dissolving in supercritical water, together with silica, which is why you often find gold in quartz veins. The relevance to asteroids is that processing does not happen in most because they are not big enough to generate the required heat. The relevance now is that the elements you want will either be bound up with silicates, or be scattered randomly through the bulk. To get the metals out, you have to get rid of the silicates, and if you look at the figures, the copper content is actually less than in our ores on earth. Now look at the mining wastes on Earth, and ask yourself what would you do with that in space? (There is an answer – build space stations with rocky shells.)

So why do we think of mining asteroids. One reason comes from asteroid Psyche. One scientific paper once claimed asteroid had a density as high as 7.6 g/cm cubed. That would clearly be worth mining, because the iron would also dissolve nickel, cobalt, platinum, gold, etc. You will various news items that wax on about how this asteroid alone would solve our problems and make everyon extremely rich. However, other papers have published values as low as 1.4 g/cm cubed, and the average value is about 3.5 g/cm cubed (which is what it would be if it were solid basalt). 

Why the differences? Basically because density depends on the mass (determined by gravitational interactions) and volume.  The uncertainty in the volume, thanks to observational uncertainty due to the asteroid being so far away and the fact it is not round, can give an error of up to 50%. The mass requires very accurate measurements when near something else and again huge errors are possible.

So the question then is, if someone wants to get metals out of asteroids, how will they do it? If the elements are there as oxides or sulphides, what do you do about that? On Earth you heat with coal and air, followed by coal. You cannot do that in space. On Earth, minerals can be concentrated by various means that use liquids, such as froth flotation, but you cannot do that easily in space because first liquids like water are scarce, and second, if you have them, unless they are totally enclosed they boil off into space. Flotation requires “gravity”, which requires a centrifuge. Possible, but very expensive,If you were building a giant space station, yes, asteroids would be valuable because the cost of getting components from Earth is huge, but we still need technology to refine them. Otherwise the cost of getting the materials to Earth would be horrifying. Be careful if you see an investment offering.

No Phosphine on Venus

Some time previouslyI wrote a blog post suggesting the excitement over the announcement that phosphine had been discovered in the atmosphere of Venus ( I outlined a number of reasons why I found it difficult to believe it. Well, now we find in a paper submitted to Astronomy and Astrophysics ( we find the conclusion that the 12th-order polynomial fit to the spectral passband utilised in the published study leads to spurious results. The authors concluded the published 267-GHz ALMA data provide no statistical evidence for phosphine in the atmosphere of Venus.

It will be interesting to see if this denial gets the same press coverage as “There’s maybe life on Venus” did. Anyway, you heard it here, and more to the point, I hope I have showed why it is important when very unexpected results come out that they are carefully examined.

New Zealand Volcanism

If you live in New Zealand, you are aware of potential natural disasters. Where I live, there will be a major earthquake at some time, but hopefully well in the future. In other places there are volcanoes, and some are huge. Lake Rotorua is part of a caldera from a rhyolite explosion about 220,000 years ago that threw up at least 340 cubic kilometers of rock. By comparison, the Mount St Helens eruption ejected in the order of 1 cubic km of rock.  Taupo is even worse. It started erupting about 300,000 years ago and last erupted about 1800 years ago, when it devastated an area of about 20,000 square km with a pyroclastic surge and its caldera left a large lake (616 square kilometers area). Layers of ash a hundred meters deep covered nearby land. The Oranui event, about 27,000 years ago sent about 1100 cubic km of debris into the air, and was a hundred times more powerful than Krakatoa. Fortunately, these supervolcanoes do not erupt very often, although Taupo is also uncomfortably frequent, having up to 26 smaller eruptions between Oranui and the latest one. However, as far as we know, nobody has died in these explosions, largely because there were no people in New Zealand until well after the last one, the Maoris arriving somewhere like 1350 AD.

The most deadly eruption in New Zealand was Tarawera. Tarawera is a rhyolite dome, but apparently the explosion was basaltic.  Basaltic eruptions, like in Hawaii, while destructive if you are in the way of a flow, are fairly harmless because the lava simply flows out like a very slow moving river. Escape should be possible, but some eruptions, like Tarawera, become explosive too. The rhyolite eruptions like those at Taupo are explosive because molten rhyolite is often very wet, so when the pressure comes off as the magma comes to the surface, the steam simply sends it explosively upwards, but basaltic volcanoes are different. A recent article in Physics World explains why there are different outcomes for essentially the same material.

Basaltic magmas are apparently less viscous, and as the magma comes to the surface, the gases and steam are vented and the magma simply flows out, so what you get are clouds of steam and gas, often with small lumps of molten magma which gives a “fireworks” display, and a gently flowing river of magma. It turns out that the differences actually depend on the flow rate. If the flow rate is slow, or at least how the theory runs, the gases escape and the magma flows away and cools during the flow. If, however, it rises very quickly, say meters per second, it can cool at around 10 – 20 degrees per second. If it cools that quickly, the average basaltic magma forms nano-sized crystals. The theory then is, if it can get about 5% of the magma in this form, the crystals start to lock together, and when that happens the viscosity suddenly increases. Now the steam cannot escape so easily, the pressurised magma from below pushes it up, and at the surface the magma simply explodes with the steam content. That, of course, requires water, which is most likely in a subduction zone, and of course the subduction zone around New Zealand starts under the Pacific, where there is no shortage of water. It was the water content that led to the Tarawera event generate a pyroclastic surge, from which, once it starts, there is no escape, as the citizens of Pompeii would testify to if they were capable of testifying. And these sort of crises are those you cannot do anything about, other than note the warning signs and go elsewhere. The good thing about such volcanoes is that there is usually a few days warning. But if Taupo decided to erupt again, how far away is safe?

Ebook discount

From October 19 – 26, A Face on Cydonia,  the first in a series, will be discounted to 99c/99p on Amazon. On a TV program from Mars early in the 22nd century a battered butte on the Cydonia Mensae morphed into the classical face and winked. By 2129, following growing pressure suggesting a cover-up, Grigori Timoshenko forms an expedition to settle this “face” for once and for all. He recruits Fiona Bolton, a world expert in sonic viewing; Sharon Galloway, the developer of an AI digging device for a major corporation; also, Nathan Gill, a Martian settler. He has Jonathon Munro forced on him. Galloway hates Munro while Bolton hates corporates, so in a party with hidden agendas and with members hating each other, the gloss of visiting another planet soon wears thin. A story of corruption, greed, murder, the maverick, the nature of Mars, and with the problem of why would an alien race be interested in such a disparate party. Book 1 of the First Contact trilogy.

Unaffordable Houses

In New Zealand, house prices are rising at an uncomfortable rate, partly aided by a shortage of stock. Somewhere about the late 1980s a number of houses were built to “look desirable and be cheap”, but unfortunately they were built badly. Why? Because a nominal “Labour” party was hijacked by right-wingers who made the likes of Thatcher look almost left wing. Regulations were cut, the market ruled, and buildings are hard to tell how well made they are until some number of years later, when they started to fall to pieces. The consequence was that local government and a changed central government pushed out regulations, and with amendments, and from then on it became a bit of a nightmare to build. Further, Councils put restrictions on land use so developers began land banking, thus raising the price of available land to high levels. Prices rose dramatically, but houses were immediately bought because interest rates tumbled. I thought we might be unusual here, but I recently found an article in The Economist” on house prices. Apparently the New Zealand situation is occurring across most Western countries. Germany apparently has had an increase of 11% over the previous year, while South Korea and parts of China have had to tighten rules for buyers.

The Economist stated monetary policy is partly to blame. Cutting interest rates mean borrowers can afford bigger mortgages and others find it easier to manage existing loans. On the other hand obtaining the mortgage is far from easier as the banks are worried about the long-term effects of the virus. In America 60% of bank loan officers have tightened the requirements for borrowing. However, landlords are willing to pay more because the perceived return on other assets has fallen. That is why stock prices are rising, despite the fact that economies are in deep trouble. The quantitative easing is sending money into the economies, but too much is going to those who wish to invest rather than to those who want to buy consumables. Investing in new companies or new construction would be virtuous, but these guys want a quick effort-free result, in which case there is nowhere else for that money to go other than existing assets. Meanwhile the moderately richer people can liquidate some other assets, and particularly bank deposits, which now return very little and pay more for houses. Sorry, poor, but your rent will go up because these guys are not running a charity.

It should be noted that many governments claim that quantitative easing is not inflationary. Actually, it is, but we must recall relativity. It devalues the money relative to what would have happened had it not happened. Keynes would argue that is a highly desirable outcome, but only if the debt so generated is paid back when times improve.

Fiscal policy is also a problem. In a normal recession, people lose their jobs and as their income is insufficient, foreclosures drag house prices down, which leaves ex-homeowners with a blemish on their credit history, making further borrowing harder. Thus the supply of houses increases and the number of people able to get a mortgage falls, which leads to cheaper houses. However, this time the richer countries have preserved household incomes, at least for a while, through wage subsidies, furlough schemes and expanded welfare benefits. Apparently in the G7 countries, in the second quarter disposable incomes were $100 bn higher than before the pandemic. Go figure! A number of countries have also allowed borrowers to suspend or defer all or parts of their repayments, and some have even banned foreclosures. The governments are protecting those in debt, at the expense of those who save or are young.

There is also possibly a third factor: since it has now become desirable to work from home, many office workers are looking to buy a bigger home. This is not a bad thing regarding the poor, but it boosts the price statistics of larger houses. Accordingly, this creates an illusory aspect to house price increases, to add to the real increases elsewhere.Which raises the question, where to from here? Governments have to wind down the fiscal stimulus, and we can expect increasing unemployment to reduce demand, but supply may also decrease as investment for new houses becomes more difficult to obtain. Very low interest rates may lead to increased purchases, but it also leads to decreased savings, which means that other than printing money and inflating the economy, after the initial “sugar high” the investment needed to build new houses may dry up. As the Chinese curse reminds us, we are living in interesting times.

Fire and Environmental Changes

Last week a fire went through the little town of Ohau and destroyed about 40 homes. Some other homes have survived, with varying degrees of heat damage, but the destroyed ones are simply reduced to heaps of ash, with lumps of fractured concrete and bits of metal. Various photographs show devastation where you cannot even distinguish where the sections were, or where the houses were, except for the odd place where there was a burnt-out car frame, and you can probably assume there was a residence there. And this is not even the fire season. Strangely enough, the fire completely burnt out a narrow strip alongside the lake, but further away, the “non-scenic, non prime” properties were largely unaffected. There was a very strong wind blowing at the time, and presumably it was blowing towards the lake. Further away from the town there are large areas that are burnt out and over six thousand hectares was obliterated in a very few days.

So, you may think, the effects of global warming striking home. I would think not. Two weeks previously there was another fire nearby, but it was soon extinguished by a major snowstorm. A major snowstorm around the spring equinox is not exactly unusual, but with that sort of weather present we can hardly blame global warming for the fires.  Obviously something else was responsible. In my opinion, environmentalists.

That probably needs a simple explanation. What has happened is there is a fairly large area that local farmers had used for free grazing, but the city environmentalists, members of the Green Party, were shouting out, “No, you must preserve native species growing there. They don’t grow anywhere else in the world, and anyway, why should farmers get free grazing?” Now, is that valid or misuse of political influence. (We have MMP as a form of government, and the small Green contingent is part of the present government.)

So surely it is reasonable to preserve a unique environment? First, it is true that there are native plants there that are not found in other countries. But the predominant vegetation is NOT unique native species. Humans have seriously changed the area, and most people do not know what it was like originally. The vegetation has been altered by an infestation of wilding pines and a number of other shrubby introduced species that got out of control. 

The problem with such introduced plants is that the scrubby ones die, and unless something is done with them, they stand there, dessicated, and become excellent fuel for fires. This land was declared conservation land, but then the Conservation Department did nothing with it to get rid of the potential fuel. The argument was, the area was simply too big. They had bitten off far more than they could chew. In that case, they badly needed to let farmers graze the area. One characteristic of well-grazed land is most of that shrubbery is eaten, and the inedible ones are removed by farmers. The “they shouldn’t have free grazing” is just envy, while, “The animals might eat native plants” is correct, but this fire hardly left them intact. Failure to have some control, like grazing, over this shrubbery was simply making fuel for a fire.

The real question is, what are we trying to preserve? Humans have changed the environment. It may be reasonable to try and protect modest areas in their original form, if you can find any, but the great bulk of the area needs to be permitted to evolve, and if humans have done something to alter it, they must permit corrective action to stop phenomena like fires. Conservation is all very well, if what you are conserving is worth while, but why conserve an area of miscellaneous scrub mainly comprising plats that were never there three hundred years ago?