Asteroid (16) Psyche – Again! Or Riches Evaporate, Again

Thanks to my latest novel “Spoliation”, I have had to take an interest in asteroid mining. I discussed this in a previous post (https://ianmillerblog.wordpress.com/2020/10/28/asteroid-mining/) in which I mentioned the asteroid (16) Psyche. As I wrote, there were statements saying the asteroid had almost unlimited mineral resources. Initially, it was estimated to have a density (g/cc) of about 7, which would make it more or less solid iron. It should be noted this might well be a consequence of extreme confirmation bias. The standard theory has it that certain asteroids differentiated and had iron cores, then collided and the rock was shattered off, leaving the iron cores. Iron meteorites are allegedly the result of collisions between such cores. If so, it has been estimated there have to be about 75 iron cores floating around out there, and since Psyche had a density so close to that of iron (about 7.87) it must be essentially solid iron. As I wrote in that post, “other papers have published values as low as 1.4 g/cm cubed, and the average value is about 3.5 g/cm cubed”. The latest value is 3.78 + 0.34.

These varied numbers show how difficult it is to make these observations. Density is mass per volume. We determine the volume by considering the size and we can measure the “diameter”, but the target is a very long way away, it is small, so it is difficult to get an accurate “diameter”. The next point is it is not a true sphere, so there are extra “bits” of volume with hills, or “bits missing” with craters. Further, the volume depends on a diameter cubed, so if you make a ten percent error in the “diameter” you have a 30% error overall. The mass has to be estimated from its gravitational effects on something else. That means you have to measure the distance to the asteroid, the distance to the other asteroid, and determine the difference from expected as they pass each other. This difference may be quite tiny. Astronomers are working at the very limit of their equipment.

A quick pause for some silicate chemistry. Apart from granitic/felsic rocks, which are aluminosilicates, most silicates come in two classes of general formula: A – olivines X2SiO4 or B – pyroxenes XSiO3, where X is some mix of divalent metals, usually mainly magnesium or iron (hence their name, mafic, the iron being ferrous). However, calcium is often present. Basically, these elements are the most common metals in the output of a supernova, with magnesium being the most. For olivines, if X is only magnesium, the density for A (forsterite) is 3.27 and for B (enstatite) 3.2. If X is only iron, the density for A (fayalite) is 4.39 and for B (ferrosilite) 4.00. Now we come to further confirmation bias: to maintain the iron content of Psyche, the density is compared to enstatite chondrites, and the difference made up with iron. Another way to maintain the concept of “free iron” is the proposition that the asteroid is made of “porous metal”. How do you make that? A porous rock, like pumice, is made by a volcano spitting out magma with water dissolved in it, and as the pressure drops the water turns to steam. However, you do not get any volatile to dissolve in molten iron.

Another reason to support the iron concept was that the reflectance spectrum was “essentially featureless”. The required features come from specific vibrations, and a metal does not have any. Neither does a rough surface that scatters light. The radar albedo (how bright it is with reflected light) is 0.34, which implies a surface density of 3.5, which is argued to indicate either metal with 50% porosity, or solid silicates (rock). It also means no core is predicted. The “featureless spectrum” was claimed to have an absorption at 3 μm, indicating hydroxyl, which indicates silicate. There is also a signal corresponding to an orthopyroxene. The emissivity indicates a metal content greater than 20% at the surface, but if this were metal, there should be a polarised emission, and that is completely absent. At this point, we should look more closely at what “metal” means. In many cases, while it is used to convey what we would consider as a metal, the actual use includes chemical compounds with a  metallic element. The iron levels may be as iron sulphide, the oxide, or, as what I believe the answer is, the silicate. I think we are looking at the iron content of average rock. Fortune does not await us there.

In short, the evidence is somewhat contradictory, in part because we are using spectroscopy at the limits of its usefulness. NASA intends to send a mission to evaluate the asteroid and we should wait for that data.

But what about iron cored asteroids? We know there are metallic iron meteorites so where did they come from? In my ebook “Planetary Formation and Biogenesis”, I note that the iron meteorites, from isotope dating, are amongst the oldest objects in the solar system, so I argue they were made before the planets, and there were a large number of them, most of which ended up in planetary cores. The meteorites we see, if that is correct, never got accreted, and finally struck a major body for the first time.

Food on Mars

Settlers on Mars will have needs, but the most obvious ones are breathing and eating, and both of these are likely to involve plants. Anyone thinking of going to Mars should think about these, and if you look at science fiction the answers vary. Most simply assume everything is taken care of, which is fair enough for a story. Then there is the occasional story with slightly more detail. Andy Weir’s “The Martian” is simple. He grows potatoes. Living on such a diet would be a little spartan, but his hero had no option, being essentially a Robinson Crusoe without a Man Friday. The oxygen seemed to be a given. The potatoes were grown in what seemed to be a pressurised plastic tent and to get water, he catalytically decomposed hydrazine to make hydrogen and then he burnt that. A plastic tent would not work. The UV radiation would first make the tent opaque so the necessary light would not get in very well, then the plastic would degrade. As for making water, burning hydrazine as it was is sufficient, but better still, would they not put their base where there was ice?

I also have a novel (“Red Gold”) where a settlement tries to get started. Its premise is there is a main settlement with fusion reactors and hence have the energy to make anything, but the main hero is “off on his own” and has to make do with less, but can bring things from the main settlement. He builds giant “glass houses” made with layers of zinc-rich glass that shield the inside from UV radiation. Stellar plasma ejections are diverted by a superconducting magnet at the L1 position between Mars and the sun (proposed years before NASA suggested it) and the hero lives in a cave. That would work well for everything except cosmic radiation, but is that going to be that bad? Initially everyone lives on hydroponically grown microalgae, but the domes permit ordinary crops. The plants grow in treated soil, but as another option a roof is put over a minor crater and water provided (with solar heating from space) in which macroalgae grow and marine microalgae, as well as fish and other species, like prawns. The atmosphere is nitrogen, separated from the Martian atmosphere, and some carbon dioxide, and the plants make oxygen. (There would have to be some oxygen to get started, but plants on Earth grew without oxygen initially.)

Since then there have been other quite dramatic proposals from more official sources that assume a lot of automation to begin with. One of the proposals involves constructing huge greenhouses by covering a crater or valley. (Hey, I suggested that!) but the roof is flat and made of plastic, the plastic being made from polyethylene 2,5-furandicarboxylate, a polyester made from carbohydrates grown by the plants. This is used as a bonding agent to make a concrete from Martian rock. (In my novel, I explained why a cement is very necessary, but there are limited uses.) The big greenhouse model has some limitations. In this, the roof is flat, and in essentially two layers, and in between are vertical stacks of algae growing in water. The extra value here is that water filters out the effect of cosmic rays, although you need several meters of it. Now we have a problem. The idea is that underneath this there is a huge habitat, and for every cubic meter of water, we have one tonne mass, and on Mars, about 0.4 tonne of force on the lower flat deck. If this bottom deck is the opaque concrete, then something bound by plastic adhesion will slip. (Our concrete on bridges is only inorganic, and the binding is chemical, not physical, and further there is steel reinforcing.) Below this there would need to be many weight-bearing pillars. And there would need to be light generation between the decks (to get the algae to grow) and down below. Nuclear power would make this easy. Food can be grown as algae in between decks, or in the ground down below.

As I see it, construction of this would take quite an effort and a huge amount of materials. The concept is the plants could be grown to make the cement to make the habitat, but hold on, where are the initial plants going to grow, and who/what does all the chemical processing? The plan is to have that in place from robots before anyone gets there but I think that is greatly overambitious. In “Red Gold” I had the glass made from regolith processed with the fusion energy. The advantage of glass over this new suggestion is weight; even on Mars with its lower gravity millions of tonnes remains a serious weight. The first people there will have to live somewhat more simply.

Another plan that I have seen involves finding a frozen lake in a crater, and excavating an “under-ice” habitat. No shortage of water, or screening from cosmic rays, but a problem as I see it is said ice will melt from the heat, erode the bottom of the sheet, and eventually it will collapse. Undesirable, that is.

All of these “official” options use artificial lighting. Assuming a nuclear reactor, that is not a problem in itself, although it would be for the settlement under the ice because heat control would be a problem. However, there is more to getting light than generating energy. What gives off the light, and what happens when its lifetime expires? Do you have to have a huge number of spares? Can they be made on Mars?

There is also the problem with heat. In my novel I solved this with mirrors in space focussing more sunlight on selected spots, and of course this provides light to help plants grow, but if you are going to heat from fission power a whole lot more electrical equipment is needed. Many more things to go wrong, and when it could take two years to get a replacement delivered, complicated is what you do not want. It is not going to be that easy.

Why Plate Tectonics?

How did plate tectonics start? Why has Earth got them and none of the rocky planets have, at least as far as we know? In my ebook “Planetary Formation and Biogenesis” my explanation as to one of the reasons for why plate tectonics are absent on Mars is that the Martian basaltic mantle appears to have about 17% iron oxide whle Earth has 7 – 11%. This means it cannot make eclogite whereas Earth’s basalt can. Eclogite is a particularly dense silicate and it is only made under serious pressure. 

To see the significance, we have to ask ourselves how plate tectonics works. The core generates hot spots, and hotter mantle material rises and has to push aside other rock, and we get what we call seafloor spreading, although it does not have to be underwater. The African rift valley is an example, in this case a relatively new example where the African plate is dividing, and eventually will have sea between Somalia and the Nubian zone. Similarly, the Icelandic volcanoes are due to “seafloor spreading”. Thus matter coming up pushes the surface plates aside, but then what? On Mars, the cold basalt has nowhere to go so it forms what is called a “stagnant lid”, and heat can only escape through volcanism. On Mars, this resulted in quite significant volcanism about three and a half billion years ago, then this more or less stopped, although not as much as some think because there is evidence of volcanic eruptions around Elysium within the last two million years. The net result is the “lid” gradually gets thicker, and stronger, which means the heat loss of the Martian mantle is actually much less than that of Earth.

On Earth, what happens is that as the basaltic plates get pushed aside, one goes under another, and this is where then eclogite becomes relevant. As the plate goes down, the increased pressure causes the basalt to form eclogite, and because it is denser than its surroundings, gravity makes it go deeper. It is this pull subduction that keeps plate tectonics going.

So, what about Venus? The usual answer is that Venus had a stagnant lid, but at certain intervals the internal heat is so great there is a general overturn and there is a general resurfacing. However, maybe that is not exactly correct. Our problem with Venus is we cannot see the surface thanks to the clouds. The best we can manage is through radar, and recent (June, 2021) information has provided some surprises (Byrne, et al.,   https://doi.org/10.1073/pnas.2025919118).  Basically, what was found was evidence that many of the lowlands had broken into crustal blocks and these blocks are moving relative to each other, in the same way as pack ice moves. The cause would be mantle convection that stresses the crust. The Venusian crust has many landforms, including thin belts where crust has been pushed together to form ridges, or pulled apart to form troughs. However, these ones tend to encompass low-lying regions that are not deformed, but rather appear to be individual blocks that shift, rotate and slide past each other. The authors suggest this what Earth was like before plate tectonics got going.

As to why they started here and not there has no obvious answer. The fact that Earth rotates far more quickly will generate much stronger Coriolis forces. It may be that the absence of water on Venus removes a potential lubricant, but that seems unlikely if blocks of crust are moving. My personal view is that one key point is it needs something to force the crust downwards. Eclogite may pull it down, but something has to push the basalt down to force it to make eclogite. My guess here is that Earth has one thing the other rocky planets do not have: granitic continents. Granite floats on basalt, so if a basaltic mass was pushed against a significant granitic mass, the granite would slide over the top and its weight would push the basalt down. When it made eclogite, the denser basalt would continue its downward motion, pulling a plate with it. Is that right? Who knows, but at least it looks plausible to me.

A Discovery on Mars

Our space programs now seem to be focusing in the increasingly low concentrations or more obscure events, as if this will tell us something special. Recall earlier there was the supposed finding of phosphine in the Venusian atmosphere. Nothing like stirring up controversy because this was taken as a sign of life. As an aside, I wonder how many people actually have ever noticed phosphine anywhere? I have made it in the lab, but that hardly counts. It is not a very common material, and the signal in the Venusian atmosphere was almost certainly due to sulphur dioxide. That in itself is interesting when you ask how would that get there? The answer is surprisingly simple: sulphuric acid is known to be there, and it is denser, and might form a fog or even rain, but as it falls it hits the hotter regions near the surface and pyrolysis to form sulphur dioxide, oxygen and water. These rise, the oxygen reacts with sulphur dioxide to make sulphur trioxide (probably helped by solar radiation), which in turn reacts with water to form sulphuric acid, which in turn is why the acid stays in the atmosphere. Things that have a stable level on a planet often have a cycle.

In February this year, as reported in Physics World, a Russian space probe detected hydrogen chloride in the atmosphere of Mars after a dust storm occurred. This was done with a spectrometer that looked at sunlight as it passed through the atmosphere, and materials such as hydrogen chloride would be picked up as a darkened line at the frequency for the bond vibration in the infrared part of the spectrum. The single line, while broadened due to rotational options, would be fairly conclusive. I found the article to be interesting for all sorts of reasons, one of which was for stating the obvious. Thus it stated that dust density was amplified in the atmosphere during a global dust storm. Who would have guessed that? 

Then with no further explanation, the hydrogen chloride could be generated by water vapour interacting with the dust grains. Really? As a chemist my guess would be that the dust had wet salt on it. UV radiation and atmospheric water vapour would oxidise that, to make at first sodium hypochlorite, like domestic bleach and then hydrogen.  From the general acidity we would then get hydrogen chloride and probably sodium carbonate dust. They were then puzzled as to how the hydrogen chloride disappeared. The obvious answer is that hydrogen chloride would strongly attract water, which would form hydrochloric acid, and that would react with any oxide or carbonate in the dust to make chloride salts. If that sounds circular, yes it is, but there is a net degradation of water; oxygen or oxides would be formed, and hydrogen would be lost to space. The loss would not be very great, of course, because we are talking about parts per billion in a highly rarefied upper atmosphere and only during a dust storm.

Hydrogen chloride would also be emitted during volcanic eruptions, but that is probably able to be eliminated here because Mars no longer has volcanic eruptions. Fumarole emissions would be too wet to get to the upper atmosphere, and if they occurred, and there is no evidence they still do, any hydrochloric acid would be expected to react with oxides, such as the iron oxide that makes Mars look red, rather quickly.  So the unfortunate effect is that the space program is running up against the law of diminishing returns. We are getting more and more information that involves ever-decreasing levels of importance. Rutherford once claimed that physics was the only science – the rest was stamp collecting.  Well, he can turn in his grave because to me this is rather expensive stamp collecting.

Is There a Planet 9?

Before I start, I should remind everyone of the solar system yardstick: the unit of measurement called the Astronomical Unit, or AU, which is the distance from Earth to the Sun. I am also going to define a mass unit, the emu, which is the mass of the Earth, or Earth mass unit.

As you know, there are eight planets, with the furthest out being Neptune, which is 30 AU from the Sun. Now the odd thing is, Neptune is a giant of 17 emu, Uranus is only about 14.5 emu, so there is more to Neptune than Uranus, even though it is about 12 AU further out. So, the obvious question is, why do the planets stop at Neptune, and that question can be coupled with, “Do they?” The first person to be convinced there had to be at least one more was Percival Lowell, he of Martian canal fame, and he built himself a telescope and searched but failed to find it. The justification was that Neptune’s orbit appeared to be perturbed by something. That was quite reasonable as Neptune had been found by perturbations in Uranus’ orbit that were explained by Neptune. So the search was on. Lowell calculated the approximate position of the ninth planet, and using Lowell’s telescope, Clyde Tombaugh discovered what he thought was planet 9.  Oddly, this was announced on the anniversary of Lowell’s birthday, Lowell now being dead. As it happened, this was an accidental coincidence. Pluto is far too small to affect Neptune, and it turns out Neptune’s orbit did not have the errors everyone thought it did – another mistake. Further, Neptune, as with the other planets has an almost circular obit but Pluto’s is highly elliptical, spending some time inside Neptune’s orbit and sometimes as far away as 49 AU from the Sun. Pluto is not the only modest object out there: besides a lot of smaller objects there is Quaoar (about half Pluto’s size) and Eris (about Pluto’s size). There is also Sedna, (about 40% Pluto’s size) that has an elliptical orbit that varies the distance to the sun from 76 AU to 900 AU.

This raises a number of questions. Why did planets stop at 30 AU here? Why is there no planet between Uranus and Neptune? We know HR 8977 has four giants like ours, and the Neptune equivalent is about 68 AU from the star, and that Neptune-equivalent is about 6 times the mass of Jupiter. The “Grand Tack” mechanism explains our system by arguing that cores can only grow by major bodies accreting what are called planetesimals, which are bodies about the size of asteroids, and cores cannot grow further out than Saturn. In this mechanism, Neptune and Uranus formed near Saturn and were thrown outwards and lifted by throwing a mass of planetesimals inwards, the “throwing”: being due to gravitational interactions. To do this there had to be a sufficient mass of planetesimals, which gets back to the question, why did they stop at 30 AU?

One of the advocates for Planet 9 argued that Planet 9, which was supposed to have a highly elliptical orbit itself, caused the elliptical orbits of Sedna and some other objects. However, this has also been argued to be due to an accidental selection of a small number of objects, and there are others that don’t fit. One possible cause of an elliptical orbit could be a close encounter with another star. This does happen. In 1.4 million years Gliese 710, which is about half the mass of the Sun, will be about 10,000 AU from the Sun, and being that close, it could well perturb orbits of bodies like Sedna.

Is there any reason to believe a planet 9 could be there? As it happens, the exoplanets encylopaedia lists several at distances greater that 100 AU, and in some case several thousand AU. That we see them is because they are much larger than Jupiter, and they have either been in a good configuration for gravitational lensing or they are very young. If they are very young, the release of gravitational energy raises them to temperatures where they emit yellow-white light. When they get older, they will fade away and if there were such a planet in our system, by now it would have to be seen by reflected light. Since objects at such great distances move relatively slowly they might be seen but not recognized as planets, and, of course, studies that are looking for something else usually encompass a wide sky, which is not suitable for planet searching.For me, there is another reason why there might be such a planet. In my ebook, “Planetary Formation and Biogenesis” I outline a mechanism by which the giants form, which is similar to that of forming a snowball: if you press ices/snow together and it is suitably close to its melting point, it melt-fuses, so I predict the cores will form from ices known to be in space: Jupiter – water; Saturn – methanol/ammonia/water; Uranus – methane/argon; Neptune – carbon monoxide/nitrogen. If you assume Jupiter formed at the water ice temperature, the other giants are in the correct place to within an AU or so. However, there is one further ice not mentioned: neon. If it accreted a core then it would be somewhere greater than 100 AU.  I cannot be specific because the melting point of neon is so low that a number of other minor and ignorable effects are now significant, and cannot be ignored. So I am hoping there is such a planet there.

Living Near Ceres

Some will have heard of Gerard O’Neill’s book, “The High Frontier”. If not, see https://en.wikipedia.org/wiki/The_High_Frontier:_Human_Colonies_in_Space. The idea was to throw material up from the surface of the Moon to make giant cylinders that would get artificial gravity from rotation, and people could live their lives in the interior with energy being obtained in part by solar energy. The concept was partly employed in the TV series “Babylon 5”, but the original concept was to have open farmland as well. Looks like science fiction, you say, and in fairness I have included such a proposition in a science fiction novel I am currently writing, However, I have also read a scientific paper on this topic (arXiv:2011.07487v3) which appears to have been posted on the 14th January, 2021. The concept is to put such a space settlement using material obtained from the asteroid Ceres, and orbiting near Ceres.

The proposal is ambitious, if nothing else. The idea is to build a number of habitats, and to ensure such habitats are not too big but they stay together they are tethered to a megasatellite, which in turn will grow and new settlements are built. The habitats spin in such a way to attain a “gravity” of 1 g, and are attached to their tethers by magnetic bearings that have no physical contact between faces, and hence never wear. A system of travel between habitats proceeds along the tethers. Rockets would be unsustainable because the molecules they throw out to space would be lost forever.

The habitats would have a radius of 1 km, a length of 10 km, and have a population of 56,700, with 2,000 square meters per person, just under 45% of which would be urban. Slightly more scary would be the fact it has to rotate every 1.06 minutes. The total mass per person would be just under 10,000 t, requiring an energy to produce it of 1 MJ/kg, or about 10 GJ.

The design aims to produce an environment for the settlers that has Earth-like radiation shielding, gravity, and atmosphere. It will have day/night on a 24 hr cycle with 130 W/m^2 insolation, similar to southern Germany, and a population density of 500/km^2, similar to the Netherlands. There would be fields, parks, and forests, no adverse weather, no natural disasters and ultimately it could have a greater living area than Earth. It will be long-term sustainable. To achieve that, animals, birds and insects will be present, i.e.  a proper ecosystem. Ultimately it could provide more living area than Earth. As can be seen, that is ambitious. The radiation shielding involves 7600 kg/m^2, of which 20% is water and the rest silicate regolith. The rural spaces have a 1.5 m depth of soil, which is illuminated by the sunlight. The sunlight is collected and delivered from mirrors into light guides. Ceres is 2.77 times as far as Earth from the sun, which means the sunlight is only about 13% as strong as at Earth, so over eight times the mirror collecting are is required for every unit area to be illuminated to get equivalent energy. 

The reason cited for proposing this to be at Ceres is that Ceres has nitrogen. Actually, there are other carbonaceous asteroids, and one that is at least 100 km in size could be suitable. Because Ceres’ gravity is 0.029 times that of Earth, a space elevator could be feasible to bring material cheaply from the dwarf planet, while a settlement 100,000 km from the surface would be expected to have a stable orbit.

In principle, there could be any number of these habitats, all linked together. You could have more people living there than on Earth. Of course there are some issues with the calculation. The tethering of habitats, and of giving the habitats sufficient strength requires about 5% of the total mass in the form of steel. Where does the iron come from? The asteroids have plenty of iron, but the form is important. How will it be refined? If it is on the form of olivine or pyroxene, then with difficulty. Vesta apparently has an iron core, but Vesta is not close, and most of the time, because it has a different orbital period, it is very far away.But the real question is, would you want to live in such a place? How much would you pay for the privilege? The cost of all this was not estimated, but it would be enormous so most people could not afford it. In my opinion, cost alone is sufficient that this idea will not see the light of day.

Unravelling Stellar Fusion

Trying to unravel many things in modern science is painstaking, as will be seen from the following example, which makes looking for a needle in a haystack relatively easy. Here, the requirement for careful work and analysis can be seen, although less obvious is the need for assumptions during the calculations, and these are not always obviously correct. The example involves how our sun works. The problem is, how do we form the neutrons needed for fusion in the star’s interior? 

In the main process, the immense pressures force two protons form the incredibly unstable 2He (a helium isotope). Besides giving off a lot of heat there are two options: a proton can absorb an electron and give off a neutrino (to conserve leptons) or a proton can give off a positron and a neutrino. The positron would react with an electron to give two gamma ray photons, which would be absorbed by the star and converted to energy. Either way, energy is conserved and we get the same result, except the neutrinos may have different energies. 

The dihydrogen starts to operate at about 4 million degrees C. Gravitational collapse of a star starts to reach this sort of temperature if the star has a mass at least 80 times that of Jupiter. These are the smaller of the red dwarfs. If it has a mass of approximately 16 – 20 times that of Jupiter, it can react deuterium with protons, and this supplies the heat to brown dwarfs. In this case, the deuterium had to come from the Big Bang, and hence is somewhat limited in supply, but again it only reacts in the centre where the pressure is high enough, so the system will continue for a very long time, even if not very strongly.

If the temperatures reach about 17 million degrees C, another reaction is possible, which is called the CNO cycle. What this does is start with 12C (standard carbon, which has to come from accretion dust). It then adds a proton to make 13N, which loses a positron and a neutrino to make 13C. Then come a sequence of proton additions to make 14N (most stable nitrogen), then 15O, which loses a positron and a neutrino to make 15N, and when this is struck by a proton, it spits out 4He and returns to 12C. We have gone around in a circle, BUT converted four hydrogen nuclei to 4helium, and produced 25 MeV of energy. So there are two ways of burning hydrogen, so can the sun do both? Is it hot enough at the centre? How do we tell?

Obviously we cannot see the centre of the star, but we know for the heat generated it will be close to the second cycle. However, we can, in principle, tell by observing the neutrinos. Neutrinos from the 2He positron route can have any energy but not more than a little over 0.4 MeV. The electron capture neutrinos are up to approximately 1.1 MeV, while the neutrinos from 15O are from anywhere up to about 0.3 MeV more energetic, and those from 13N are anywhere up to 0.3 MeV less energetic than electron capture. Since these should be of the same intensity, the energy difference allows a count. The sun puts out a flux where the last three are about the same intensity, while the 2He neutrino intensity is at least 100 times higher. (The use of “at least” and similar terms is because such determinations are very error prone, and you will see in the literature some relatively different values.) So all we have to do is detect the neutrinos. That is easier said than done if they can pass through a star unimpeded. The way it is done is if a neutrino accidentally hits certain substances capable of scintillation it may give off a momentary flash of light.

The first problem then is, anything hitting those substances with enough energy will do it. Cosmic rays or nuclear decay are particularly annoying. So in Italy they built a neutrino detector under1400 meters of rock (to block cosmic rays). The detector is a sphere containing 300 t of suitable liquid and the flashes are detected by photomultiplier tubes. While there is a huge flux of neutrinos from the star, very few actually collide. The signals from spurious sources had to be eliminated, and a “neutrino spectrum” was collected for the standard process. Spurious sources included radioactivity from the rocks and liquid. These are rare, but so are the CNO neutrinos. Apparently only a few counts per day were recorded. However, the Italians ran the experiment for 1000 hours, and claimed to show that the sun does use this CNO cycle, which contributes about 1% of the energy. For bigger stars, this CNO cycle becomes more important. This is quite an incredible effort, right at the very edge of detection capability. Just think of the patience required, and the care needed to be sure spurious signals were not counted.

Water on the Moon

The Moon is generally considered to be dry. There are two reasons for that. The first is the generally accepted model for the formation of our moon is that something about the size of Mars collided with Earth and sent a huge amount of silica vapours into space at temperatures of about 10,000 degrees Centigrade (which is about twice as hot as the average surface of the sun) and much of that (some say about half) condensed and accreted into the Moon. Because the material was so hot and in a vacuum, all water should have been in the gas phase, and very little would condense so the Moon should be anhydrous deep in the interior. The fact its volcanic emissions have been considered to be dry is taken to support that conclusion. And thus with circular logic, it supports the concept that Earth formed by objects as large as Mars colliding and forming the planet.

The second is the rocks brought back by Apollo were considered to be anhydrous. That was because the accepted paradigm for the Moon formation required it to be dry. The actual rocks, on heating to 700 degrees Centigrade, were found to have about 160 ppm of water. On the basis that the accepted paradigm required them to be anhydrous it was assumed the rocks were contaminated with water from Earth. The fact that the deuterium levels of the hydrogen atoms in this water corresponded to solar hydrogen and not Earth’s water was ignored. That could not be contamination. Did that cause us to revise the paradigm? Heavens no. Uncomfortable facts that falsify the accepted theory have to be buried and ignored.

Recently, two scientific papers have concluded that the surface of the Moon contains water. Yay! If we go there, there is water to drink. Well, maybe. First, let’s look at how we know. The support is from infrared spectra, where a signal corresponding to the O-H bond stretching mode is seen. It has been known for some time that such signals have been detected on the Moon, but this does not mean there is water, since it could also arise from entities with, say, a Si-O-H group. Accordingly, it could come from space weathered rock, and in this context, signal strength increases towards the evening, which would happen if the rocks reacted with solar wind. The heating of rocks with these groups would give off water, so the Moon might still be technically dry but capable of providing water. Further examination of apatites brought back from Apollo suggested the interior could have water up to about 400 ppm.

How could the interior be wetter? That depends on how it formed. In my ebook, “Planetary Formation and Biogenesis” I surveyed the possibilities, and I favour the proposal outlined by Belbruno, E., Gott, J.R. 2005. Astron. J. 129: 1724–1745. Quite simply, Theia, the body that collided with Earth, formed at one of the Lagrange points. I favour L4. Such a body there would accrete by the same mechanism as Earth, which explains why it has the same isotopes, and while its orbit there is stable while it is small, as soon as it becomes big it gets dislodged. It would still collide with Earth, it would still get hot but need not vaporize. Being smaller, the interior may trap its water. There is evidence from element abundance that anything that would remain solid on the surface at about 1100 degrees Centigrade was not depleted, which means that is roughly the maximum temperature reached, and that would not vaporize silicates.

In one of the new papers, the signals from the surface have included the H-O-H bending frequency, which means water. Since it has not evaporated off into space it is probably embedded in rocks and may have originated from meteorites that crashed into the Moon, where they melted on impact and embedded the water they brought. There is also ice in certain polar craters that never see the sunlight, and above latitude 80 degrees, there are a number of such small craters.So, what does this mean for settlement? If the concentration is 5 ppm, to get 5 kg of water you would have to process a thousand tonne of rock, which would involve heating it to about seven hundred degrees Centigrade, holding it there, and not letting any water escape. The polar craters have ice up to a few per cent, but that ice also contains ammonia, hydrogen sulphide, and some other nasties, and since the craters never see sunlight the outside temperature is approximately two hundred degrees Centigrade below zero. You will see proposals that future space ships will use hydrogen and oxygen made from lunar water. That would require several thousand tonne of water, which would involve processing a very large amount of rock. It will always be easier to get water from the Sahara desert than the lunar surface, but it is there and could help maintain a settlement with careful water management.

Support for a Predicted Mechanism!

What is the point of a scientific theory? The obvious one is that if you understand you can predict what will happen if you have reason to have that proposition present.  Unfortunately, you can lay down the principles and not make the specific prediction because you cannot foresee all the possible times it might be relevant. What sparked this thought is that about a decade ago I published an ebook called “Planetary Formation and Biogenesis”. The purpose of this was in part because the standard theory starts off by assuming that somehow things called planetesimals form. These were large asteroids, a few hundred km in size, and then these formed planets through their mutual gravity. However, nobody had any idea at all how these planetesimals formed; they were simply assumed as necessary on the assumption that gravity was the agent that formed the planets. On a personal level, I found this to be unsatisfactory.

I am restricting the following to what happens with icy bodies; the rocky ones are a completely different story. We start with highly dispersed dust because the heavy elements are formed in a supernova, in which these gases fly out at a very high speed. In one supernova, one hour after initiation, matter was flying out at 115,000 km/second, and it takes a long time to slow down. However, eventually it cools, gets embedded in a gas cloud and some chemical reactions take place. Most of the oxygen eventually reacts with something. All the more reactive elements like silicon or aluminium react, and the default for oxygen is to form water with hydrogen. The silicon, magnesium, calcium and aluminium oxides form solids, but they form one link at a time and cannot rearrange. This leaves a dispersion of particles that make smoke particles look large. If two such “particles” get close enough, because the chemical bonds are quite polar in these particular oxides, they attract each other and because they are reactive, they can join. This leads to a microscopic mass of tangled threads since each junction is formed on the exterior. So we end up with a very porous solid with numerous channels. These channels incorporate gases that are held to the channel surfaces. In the extreme cold of space, when these gases are brought close together on these surfaces they solidify to form ices. These solids filled with ices have been formed in the laboratory.

My concept of how icy bodies accrete goes like this. As the dust comes into an accretion disk where a star is forming, as it approaches the star it starts to warm. If particles collide at a temperature a little below the melting point of an ice they contain, the heat of collision melts the ice, the melt flows between the bodies then refreezes, gluing the bodies together. The good news is this has been demonstrated very recently in the laboratory for nanometer-sized grains of silicates coated with water ice (Nietadi et al., Icarus, (2020) 113996) so it works. As the dust gets warmer than said melting point, that ice sublimes out, which means there are four obvious different agents for forming planets through ices. In increasing temperatures these are nitrogen/carbon monoxide (Neptune and the Kuiper Belt); argon/methane (Uranus); methanol/ammonia/water (Saturn); and water (Jupiter). The good news is these planets are spread relatively to where expected, assuming the sun’s accretion disk was similar to others. So, in one sense I had a success: my theoretical mechanism gave planetary spacings consistent with observation, and now the initial mechanism of joining for very small-scale particles has been shown to work.

But there was another interesting point. Initially, when these fluffy pieces meet, they will join to give a bigger fluffy piece. This helps accretion because if larger bodies collide, the fluff can collapse, making the impact more inelastic and thus dispersing collisional energy. Given a reasonable number of significant collisions, the body will compact. If, however, there are some late gentle acquisitions of largish fluffy masses, that fluff will remain.Unfortunately, I did not issue a general warning on this, largely because nobody can think of everything, and also I did not expect that to be relevant to any practical situation now.  Rather unexpectedly, it was. You may recall that the European Space Agency landed the probe Philae on comet 67P/Churyumov–Gerasimenko, which made a couple of bounces and fell down a “canyon”, where it lay on its side. The interesting thing is the second “bounce” was not really a bounce. The space agency has been able to use the imprint of the impact to measure the strength of the ice, and  found it to be “softer than the lightest snow, the froth on your cappuccino or even the bubbles in your bubble bath.” This particular “boulder” on the outside of the comet is comprised of my predicted fluff. It feels good when something comes right. And had ESA read my ebook, maybe they would have designed Philae slightly differently.

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 (https://ianmillerblog.wordpress.com/2020/09/23/phosphine-on-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 (https://arxiv.org/pdf/2010.09761.pdf) 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.