How to Form a Theory, in this case, Why Does Earth Have Continents?

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As a response to a previous post that mentioned continent formation, I said I should do a post on continent formation. But there is an interesting issue relating to how to form a theory, and it is, if you want to go from A to B, in this case going from a non-descript planet to one with continents and oceans, sometimes it is helpful to start by focussing on C. When I wrote my “Planetary Formation and Biogenesis”, I started by asking where did the atmosphere come from? This approach would usually be rejected by the run of the mill, on the grounds what could the atmosphere have to do with continent formation? As it happens, in my opinion everything, because it makes you focus on what happened. In my opinion, it turns out that continents and atmospheres are emergent from a common starting point.

Most people think atmospheres and water came from comets, or from chondrites. The evidence, outlined in the above ebook, is fairly clear that is wrong. For example, had our water come from comets, the amount of 36 Argon we measure differs from the requirements of the proposition by a factor of 20,000. We can disregard that. Chondrites are a more complicated issue, but the requirements of the theory are equally absent in observations. So why do these propositions persist? Basically, because everyone is too lazy to really think. They are comfortable with those.

So, what did happen? The only answer remaining is if the volatile elements did not come from space and bombard the planet, where did they come from? The evidence from Mars is reasonably clear: from below the ground, by volcanism. So, how did they get there? No physical mechanism is realistic. If you think about something like absorption on dust, you immediately realize (if you are awake and capable of realizing) that the physical attractions of nitrogen gas to solids is very weak, and comparable to that of neon. Accordingly, if physical mechanisms are realistic, there should be approximately as much neon in the atmosphere as nitrogen. There is not. To understand how atmospheres form, we need to understand what the atmospheres comprise. For the moment we ignore carbon dioxide and oxygen. The former varies due to freezing out (Mars) and being converted to lime (Earth). The latter comes from biomass photosynthesis. Instead, concentrate on nitrogen.

Consider the amount of nitrogen in planetary atmospheres. Mars has approximately 0.01 bars, Earth about 0.75 bars, Venus about 3 bars, and Mercury 0 bars. i.e. except for Mercury, the closer to the star, the more nitrogen in the atmosphere. Most people would reject the figure for Mercury on the grounds that Mercury is too small to hold an atmosphere, but that is wrong reasoning. The gravity of Mercury is over twice that of the Moon and approximately that of Mars. If the Moon ever had an atmosphere, much of it would still be there. You could say that Mars has not got much, but that is because the carbon dioxide freezes out. In some ways, Mercury could be similar. Its rotation is so slow the cold side is far colder than the Moon gets. The evidence indicates Mercury never had any significant atmosphere.

Assume Mercury never had significant gas, except maybe some carbon monoxide from the reduction of iron oxides, as some gas is needed to drive the pyroclastic volcanism that occurred briefly. What does the data in the previous paragraph suggest? This is what sorts out those who might be able to develop theories from those who won’t, and remember you have had serious help so far by my elimination of a number of things that might distract you.

The answer is reasonably simple. The amount of nitrogen increases as the temperature increases, then stops and there is none. First, dealing with Mercury. The simplest explanation is that the nitrogen was accreted chemically bound, and then released, and Mercury suggests the mechanism of release was impeded because a second agent had to be accreted, and it was too hot to do so at Mercury. That suggests the nitrogen levels depend on chemistry, and unfortunately for some, if you got that far, you cannot go further without some knowledge of chemistry. 

The simple answer is that the gases in the accretion disk comprised mainly hydrogen, helium, water, carbon monoxide, neon, and nitrogen, plus small amounts of miscellaneous. At about 1 AU, the temperatures reached about 1600 degrees Centigrade while the star was accreting. At that temperature oxides such as calcium oxide react with carbon and nitrogen to form carbides, nitrides, and some further compounds such as cyanamides. When these are accreted by a planet, the reaction with water will give you ammonia, methane, and some further compounds which lead to the origin of life. That is where the atmosphere originally came from. 

But you protest there are scientific references based on the chemical equilibria of what happens inside magma that the initial atmosphere comprised carbon dioxide and nitrogen. That is misleading because gases and the markers in magma are in different phases, and hence are not in equilibrium. In this context, rocks that captured the ancient atmosphere from 3.9 billion years ago at Isua, Greenland, have so much methane in them liquid drops can be seen. Similarly, rocks that contain seawater from 3.2 billion years ago contain as much ammonia as potassium, and significant amounts of ammonia would be lost as the seawater evaporated. (It was trapped by magma falling into the sea, as still happens in Hawaii.)

Now we can start to understand, why are there continents on Earth? The answer next week.

Gallium For Cancer

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There are a few problems in this world that affect humanity. Disease comes to mind. Cancer is one of those diseases you don’t want, but there are new treatments that appear to offer promise. One nasty version of cancer is osteosarcoma, the most common form of bone cancer. The nastiness comes from the fact it tends to strike young people. Modern treatment is unpleasant but if it has not spread, a survival rate of over 70% is possible. If it has spread when initially diagnosed, survival falls to 30%. The unpleasantness involves surgery, which means cutting out bone and putting it back together, and chemotherapy. The trouble with putting bone back together is to do so in a way that does not lead to bone fractures.

However, according to a recent publication of Physics World, a quite remarkable new treatment has emerged. Repairing and regenerating bones can be done with bioactive glasses. The glass is finely ground and introduced, where they induce bone formation by releasing calcium, phosphate and silica. At the same time, they could release therapeutic material. However, most chemotherapeutic materials would not survive the glass-making process. That is no problem, however, for inorganic oxides, and glasses containing up to five mole percent of gallium oxide has been shown to have promise. Lab trials using conditioned media showed the gallium glasses were quite cytotoxic. A top performance was the killing of 99% of the cancer cells in ten days. Some cytotoxic effects were also noted in control cells. It was felt that this was within safe limits, particularly as the localized nature of the gallium should significantly reduce side effects compared with orally administered gallium. The benefits were the highly toxic effect of the gallium-doped glass on the cancer cells with relatively minor effects on other cells, and it significantly reduced cancer cell proliferation and migration.

Tests indicated that the glasses should also help bone regeneration. The glasses gradually released calcium and phosphate ions, and under physiological pH, this led to the gradual precipitation of calcium hydroxyapatite, which is a major component of bone. The concept was that after surgery a paste could be injected into the cavity, and gradually this would encourage bone regeneration.

Gallium has been of interest for some time. 67Ga has been used to detect disease such as lymphoma following other chemotherapy treatment. The intensity of the uptake of gallium correlates with their proliferative rate. The more aggressive the tumour, the greater the uptake, and treating with gallium nitrate has had success in clinical trials, particularly with lymphomas and bladder cancer. So is gallium widely used? Seemingly not. There would appear to be three reasons. The first is it mainly works with certain aggressive tumours. The second is while it is synergistic with some treatments, it can have the opposite effect. Thus using 5-fluorouracil with gallium, we find that the effectiveness of both falls to a very low level. It appears they cancel each other out. The third is that gallium nitrate does not last long in the body, and since the gallium appears to take at least ten days to kill tumour cells, currently this requires the patient to have a drip feed over that period, which is somewhat inconvenient.

This leaves us with a situation that is so common. We have found an effect. Sometimes it seems to work like magic, at other times not so much. We don’t really understand why it works when it does, and why not at other times, although the aggressiveness is understandable. The more aggressive a tumour is, the more it demands absorption of nutrients, The faster it absorbs, the less control it will have on what it absorbs. My guess is gallium will become more widely used in the future, but only when we  understand more of its action, i.e. why does it work sometimes and not at other times? Which then raises the question, who is likely to do the research? My guess is it will not be the drug companies, because there is nothing they can make exclusively with patent protection. Gallium nitrate is not cheap; high purity costs about $6,800 / kg, but that is cheap compared with other cancer drugs, and of course, dosage is using milligrams. This is why the state should do research for the public good. Whether it will remains to be seen. Or alternatively, it could be something the United Nations could usefully do. No breath holding please.

Multicellular Life

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Many people think alien life is very unlikely because it is so improbable, as evidenced by the long time it took to happen on Earth. I disagree. I think the problem was there were too many things that had to be done first. In the previous post I mentioned that multicellular life emerged about 1.5 billion years ago. I recall seeing a paper while visiting a museum that indicated a fossil had been found in which something very closely resembling modern-day Bangia fuscopurpurea, and probably most others in the Bangiales. These are filamentous algae, essentially one cell after another in a line – essentially one-dimensional growth. However, there is obvious connectivity because they reproduce through spores, and the spore has to contain the instructions to grow the same way. One can argue this is not a great advance for life, but then again these plants are still around today. The next step up is for two dimensional growth; you get a sheet of alga, one cell thick, and Porphyra species are quite common. These may well belong to the belief, “If it ain’t broke, don’t fix it.”

However, it turns out (Science 383: 352 – 353) that fossils of similar plants have been found in China, India, Canada and Australia that are about 1.6 billion years old. Life tends to be divided into two sets: prokaryotes evolved first and some of them, cyanobacteria began to form chains. The prokaryotes have free-floating DNA. Eukaryotes pack their DNA into cells, and about two billion years ago some of them grew single cells that were quite large. The current largest single cell species of which I am aware is Caulerpa taxifolia, and its single cell can grow up to twelve inches long, a stolon runs along the surface that the plant is growing on, and from the stolon leaf-like fronds grow as do hold-fasts that anchor the cell and absorb phosphorus. All of this is one cell.

But back to the early finds. The fossils were described as Qingshania magnifica and comprised up to 20 cylindrical cells in a row with adjoining cell walls visible under  a microscope as dark rings, together with reproductive spores. Chemical tests concluded the filaments were most likely green algae. In this context, Bangia are red algae, which suggests that this multicellular life emerged more than once. Further, the fossils from different sites showed a great diversity of the way multicellular algae were put together.

Complex multicellular life took longer to evolve, and the earliest forms we know of (and we must be careful here because soft tissue is difficult to fossilize and there are not that many samples of fossils over this extended period) did not arrive until about a billion years ago. Perhaps this is not surprising since as the article says, complex eukaryotes have multiple cells that stay together, communicate with each other, and have different sizes, shapes and functions. This takes time to evolve.

Also, these early multicellular life forms may not be equivalent to their modern look-alikes. Consider the Bangia species. These have learned to occupy rather weird niches, such as the top of the tidal splash zone. They could not have evolved from single-cells there. They have also evolved an unusual reproductive strategy, or more correctly a number of strategies. The macroalgae usually have two reproductive cycles and they can appear to be quite different. One stage is the gametophyte, in which male and female plants generate sexual reproduction, and in Macrocystis pyrifera, the gametophytes are tiny, but the product of the sexual reproduction leads to sporophyte forms that can grow 60 cm a day to form plants over 45 metres long. The spores then land somewhere and form the gametophytes.

If you think that is complicated, Bangia alter their reproductive strategy depending on the environmental stresses. Beside the above strategies, the first division of a haploid spore results in two daughter cells that are different. It can also shed cells vegetatively that, if they take anchor, will grow. They did not spend the last 1.5 billion years doing nothing, but rather evolved into entities better suited to reproduce, which is the primary aim of evolution.

More on Where Are The Aliens

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Patrice Ayme wrote a very long comment in response to my post “Where are the Aliens?” so this post responds to some of the points made. I shall leave the first until last.

The first question is what is the probability of getting multi-cellular animals? Whether the point that it took four billion years to get to animals is important depends on what happened during that four billion years, and how probable was it to happen. If you accept the mechanism for planetary formation in my ebook “Planetary Formation and Biogenesis” what we start with is that most of the volatiles emitted are reduced. The evidence supports this. Atmosphere trapped in rocks from 3.8 Gy ago show the gas was mainly methane. Seawater trapped in rocks from 3.2 Gy ago are rich in ammonia. The basic premise I made was that geochemical activity also produced the necessary chemicals to get life started. So the initial life forms simply fed on what was coming from the ground, but the formation of those chemicals was “one-off” and depended on the reaction of water with rocks and materials from the accretion disk. This stage is really only viable for a planet that is Earth-sized. If it is too small, the supply of feed will run out before the life forms have evolved far enough to use scarcer resources. A particularly difficult one is nitrogen. Gaseous nitrogen is very inert chemically, and only reacts with molecules like water under electrical discharges or high energy UV radiation. Some life eventually learned how to fix nitrogen, but it took about two billion years, and it is very energy intensive. A large number of steps were required before it could manage that.

There were further problems on the way. After the planet was about 1.5 – 2 billion years old, the seawater had a very significant decline in nickel content, which was an element that catalysed much of the early anaerobic activity. Sone life forms had to evolve a new chemistry. Somewhere in the next billion years some evolved photosynthesis and a very few evolved nitrogen fixation. The production of oxygen changed the entire environment. Soluble iron II got precipitated out as iron III, which is essentially insoluble other than in acidic environments. Iron is also an important nutrient, so some way of overcoming this had to be found. Then, about 1.5 billion years ago, some algae started to form multicellular plants, and it would take probably something in the order of a billion years for multicellular plant-eaters to evolve. The filamentous and single-cell-thick algae are still present today. My point is, there was plenty to be done that filled in that time period.

The next point made was that if intelligent life evolved it might not have hands. One of the features of evolution is that it stalls when all the niches are full, but it works surprisingly quickly to fill new niches. Grasping is an important asset if you want to climb trees, and that niche will be generally available as long as there are trees with branches. But branches are a more recent evolutionary attribute. In my opinion, this is not a limitation, as climbing rock faces will also be advantaged by hands, and even in the dinosaur period, animals like troodon had hands with opposable thumbs.

The next point made was that when civilization is launched, it can fail, and not get a second chance. Difficult to argue with that. If failure eliminates that species, that will be it. Mineral availability will not be there for second attempts to accidentally discover mineral smelting.

The fifth point was that Earth has a nuclear-powered core. In my opinion, that will be common. Planets that form from the accretion disk collect all the radioactivity in that dust, which is formed from supernovae. I know some think heavy elements come from the collision of neutron stars, but most stars, as far as I know, have roughly the same proportion of various heavy elements so they will have a similar fraction of radioactive elements. Initial core formation might require tolerably recent supernovae dust.

The next question is, how likely are suitable planets? The ebook analysis suggests we need G-type or heavy K-type stars that accreted at proportional rates to Earth. The various temperature profiles in the accretion disk determine the distance from the star that the Earth equivalent will be. The evidence is that the Sun was probably a relatively fast accretor compared with other stars. The fraction of appropriately sized stars is probably about 2% before we consider accretion rate. That may cut it down by at least a factor of ten. We then need the star to eject its disk within about 1 million years following formation, and that will reduce the number of stars further. However, if I am right, meet those criteria and life becomes inevitable on that one planet per suitable star! The problem is, suitable planets are very far apart.

The last point that Patrice made was effectively the Fermi paradox: why don’t we see aliens that have been around for longer? The answer I have in my novels is most don’t want to go very far. Colonize another planet around another star, and you will never see your friends again, nor communicate with them in real time. When my grandparents settled in New Zealand, half-way around the world, there was always the possibility they could go back, and they could always send letters. Most nearby planets will be nowhere as attractive as Earth, so why go? I suppose there will always be explorers, but who is going to pay the enormous cost of sending off a space ship when there will be no message back in your lifetime, let alone a return on investment. My view is that distance may be able to be crossed  in terms of technology, but not socially.

I have had some questions on where the ebook can be found. It is available at most ebook distributors, such as Amazon, B&N, Kobo, etc.

Rocky Planet Magnetism

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In the previous post, I asked, “Where are the aliens?” Technological aliens have to come from a rocky planet, and Earth is the only rocky planet in this solar system with magnetism. That raises the question, is a magnetic field necessary for life to evolve? To understand why only Earth has such a field, we have to better understand how it is generated.

We believe it is due to the behaviour of the core, so the first step in understanding is to gain what knowledge we can about the core. About 2900 km down, the silicates give way to a ball of molten metal, which we call the outer core. This outer core has a radius of about 3,480 km, which makes it slightly larger than the planet Mars. It mainly consists of iron and nickel, with some traces of lighter elements that can combine with it, and some other metals that were dissolved in the nickel-iron. The bottom of the core is hotter than the top, and apparently the metal is more mobile, which in some ways is odd because below that is the inner core, which is believed to be solid iron/nickel. The inner core has a radius of about 1220 km, which is about70% the size of the Moon, and is supposedly at a temperature of about 5,400 degrees C, i.e. about the same temperature as the surface of the sun. The reason it is solid is presumably due to the pressure, and that is why I find it odd that the bottom of the outer core is highly mobile. Anyway, the liquid at the bottom of the outer core, like boiling water, rises, so the outer core should be well-mixed.

Which brings me to the problem, published very recently in Science Advances (https://www.science.org/doi/10.1126/sciadv.adn5562) The way we know about the core is through sonic waves. When waves meet a boundary of different impedance, some is reflected and some transmitted, so by collecting the different returns scientists can work out how many boundaries there are, and from the time taken for the return, work out how far away the boundary is. This is not a totally free run because the speed of sound depends on the density of the material, and there is a minor problem assessing that. However, there are various other relationships, such as the volumes of layers times their density gives a mass, and the total must equal the mass of the Earth. We can also measure the compressibility of a material in the laboratory, and thus calculate some densities. Anyway, assume we know how to measure the core.

Now the surprise: there is a large toroidal shaped region of the core around the equator which is a few hundred kilometers thick, where seismic waves travel about 2% slower than in the rest of the core. To be slower, they had to have less density, and that can come about by the iron incorporating lighter elements such as silicon and oxygen. This was found by taking measurements at various latitudes; the return was quicker the greater the latitude. It is also interesting to see how they found this. The major returns of sound will be simply from reflection of waves, but we can get more details because when a sonic wave comes to exit the core to go into the silicate, it too has partial reflection and partial transmission, which means the waves can bounce around within a layer for some time. You will be familiar with this effect; this is the reason why a bell ringing sounds as it does.

There is another planetary-scale process going on. The fact the bottom of the core is so hot and there is a solid inner core leads to the outer core liquid rising at right angles to the inner core. However, because the inner core is a sphere, most of the time these rising liquids are partially heading towards the poles, which leads to turbulent motion. The angular momentum of these streams is wrong for the Earth’s rotation, as is that of the metal that falls back down, with the net result there are circular flows near the inner core boundary. This turbulent flow, together with the effects of metal rising into the silicate layer, are thought to be the cause of the geodynamo and hence the Earth’s magnetic field. The reason why Venus has not got such a field is simply its rotation is so slow there is no such significant angular momentum effect. That Mars does not have such a magnetic field is probably because there is far more iron oxide in the core. The Martian core is surprisingly large, but the overall density of the planet means it cannot be nickel-iron without a lot of other light elements. According to the Insight Lander data, the outer core of Mars is liquid, but it may be there is no truly solid core. Further, the temperatures of the melt may be lower with compounds like oxides there. Iron II oxide has a melting point 200 degrees C lower than iron, while Iron III oxide has a very similar melting point to iron. That might mean that the radioactive elements are more evenly distributed within the core, which would reduce convectional forces and it may be that the silicate-core boundary is more resistant to core fragments convecting through then returning. It may be that the iron oxides tend to quench electric charge. In my opinion, we do not know why Mars has no such magnetic field.

If Earth’s magnetic field is due to the rotation of the planet, the reason it has such a higher rotational velocity than Venus is probably due to the Moon-forming collision. Had that not happened, maybe Earth would not have its magnetic field. Which raises the question, is the magnetic field critical for life? Many say so, but we really don’t know, but if it is, it is a further dampening on finding alien life because not only must there be a moon-forming collision but it must occur at the correct angle. How limiting is that? Maybe not so much as you might think if we reject the impactor Theia as being of Mars sized and instead consider it to have originated from a Lagrange point, as outlined by Belbruno, E., Gott, J.R. 2005. Where did the Moon come from? Astron. J. 129: 1724–1745, then it is easier to get the collisional angle right. The reasons why I think that is the most probable origin are outlined in my ebook “Planetary Formation and Biogenesis”.

As for limitations for aliens existing, I shall discuss some of those next week.

Where Are The Aliens?

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It would seem most likely that our fascination with exoplanets includes our desire to see if we are alone in the Universe. Aliens will live on planets, at least when not travelling or occupying space stations, and space ships and space stations will be impossible to locate unless they broadcast signals that happen to come to us. Such signals will be highly directional to prevent attenuation over large distances, and distances between stars are large. So if we want to find them, as opposed to wait until they find us, we need to find planets. But not just any planet. Nobody technological society is going to live in a gas giant, or a Neptune-sized star. We need a rocky planet. Actually, we need a lot more.

Most of the planets that we have found tend to be giants or very close to the star. That is because they are the easiest to find, so it is not surprising we have not been successful. In particular we have been unsuccessful in finding any planet that looks like Earth. The reason is fairly clear: the more like Earth a planet is, which is a small planet around a G or heavy K type star, the harder it will be to find. Obviously, the task would be easier the closer the star is to us.

There is a reason why Earth-like planets will be relatively uncommon, if you accept the mechanism of formation of planets as outlined in my ebook “Planetary Formation and Biogenesis”. Basically, to form an Earth, the rocky material has to go through two temperature phases in the accretion disk. The first heats the dust to about 1600 degrees C. This heat originates from the gas and dust falling towards the star when it is accreting. This has the effect of melting iron so it forms lumps, aluminosilicates phase separate, and certain other chemicals are formed, such as carbides, nitrides, i.e. that which will form the atmospheres later, while the iron lumps lead to the core formation later. The second temperature phase occurs when the star has finished accreting and the gas density in the disk drops away to give a temperature distribution not that much different from now. What happens, according to this theory, is that the rocky lumps formed from the hot stage group and the dust that settles between them acts as a cement by absorbing water from the accretion disk. At Earth’s distance from the star, the temperatures were suitable for separately binding aluminosilicates, which absorb more water than other silicates, which is why Earth has oceans and granitic continents.

The two temperature stages combined to give a planet in the habitable zone here, but the optimal zones do not need to be at the same distance. The distance from the accreting star for the first optimal distance depends on the rate of gas inflow because the heat comes from the potential energy lost by the gas moving starwards. The second zone depends on the brightness of the star, the rate of residual gas inflow (which can vary by several orders of magnitude) and the amount of dust as opposed to rocks. In our solar system, Mars was always too cold to form aluminosilicates and Venus too hot to absorb as much water. What happened next was after about 1 million years after the sun completed its main accretion, it blew out a massive wind that blew the accretion disk away. 

Accordingly, if that is correct, our solar system will be typical of other exoplanet systems that had comparable rates of stellar accretion AND the rapid removal of the disk. However, many/most stars take longer to expel their disks, so they continue slowly accreting. That is why I am not surprised to find there are so many giants that dwarf Jupiter, and “Neptunes” in the rocky planet zone. In the above ebook, I predicted they continue accreting and get bigger, they acquire an atmosphere that, at a certain size, will rain out water, although the hydrogen and helium will be transient. If they accrete enough of that, we have a water-world. At Neptune’s size they start accretion of hydrogen and helium.

The interesting point for me is the exoplanet LHS 1140 b, which has been found to be about 5.6 times the mass of Earth, but its density seems to be too low for a rocky planet, and more so consistent with about 9 – 19% of its mass composed of water, with an average water depth of 780 km. It is quite thrilling to find such results consistent with my earlier prediction. They have also detected an atmosphere, probably nitrogen. It is in the habitable zone, but may be covered with ice. (There is an inner planet with a mass 1.8 times that of Earth and a density of about 5 g/cm^3, which is definitely consistent with a rocky planet.) No life here, but as I mentioned above, it is great when a prediction seems to have come right.

Why Is Earth The Only Planet with Plate Tectonics?

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When, and how, did plate tectonics start? First, as we all know, plate tectonics involves large slabs of mass moving around on the surface of then Earth, and the concept was first proposed by Alfred Wegener, who noted that if you moved South America across to West Africa, the land masses fitted remarkably well. At the time this was generally regarded as an accidental coincidence, and the rest of Wegener’s theory was considered to be nonsense. Just because one person sees the truth does not mean that others will accept it!

Anyway, the general mechanism of plate tectonics is that from convection in the hot mantle, basalt rises, and when it gets to the surface it starts spreading, often from the seafloor, and that pushes surface basalt aside. There are large-scale movements of slabs of basalt (plates) that drift until the edges of a plate meet another plate, when either one goes under the other, or they push against each other leading to both buckling and forming mountain ranges. If one goes under the other, it generally takes water and carbonates with it, which leads to violent volcanism from the water, and bursts of carbon dioxide from the carbonates. The latter is critical for life because if all the carbon dioxide ended permanently in carbonates there would be no photosynthesis. It should be noted that plate tectonics is not necessary. If a planet has no plate tectonics, the convection is settled by massive outbursts of basalt. Earth is the only planet we know that has plate tectonics. Venus has a very young surface, and is argued to have resurfaced a few hundred million years ago in massive volcanism.

So the question then is, what initiates plate tectonics? It cannot be the upwelling of hot basalt because Venus does that, and Mars probably did early in its history. The one thing additional that plate tectonics has is pull subduction, which causes the recycled basalt to sink into the hot basalt and pull the rest of the basalt along with it. To do that, it needs to get denser as it goes down, and it does; the pressure forms eclogite, which as a higher density that pulls the slab down, but the question then is, what started it going down, and why does some form mountains.

The latter question is easy. Mountains form when two masses of continents collide. The continents we stand on are granitic/felsic, and have a density of about 2.5 to 3 g/cm^3. Basalt is greater than 3, so the granite floats on the basalt, somewhat like an iceberg on water. When the collide they cannot go down. But maybe that gives a clue as to how plate tectonics started. Once a basaltic plate hits such a “graniteberg” its only option is to try to slide underneath the “berg”. If the “berg” is deep enough, the basalt receives enough heat and pressure to form the eclogite. That is my speculation, but if it is true, then continental land mass had to come first. A small granitic craton would not force the basalt down.

So, to address the question of when, we have a problem: there is very little rock available older than three billion years, and none older than four billion years. The oldest clearly felsic rock appears to be about 3.5 billion years ago. The only material from the first 500 million years are a few zircons, most from the Jack Hills in Australia. In an article in Science (July 8 edition). They argue that modelling shows plate tectonics could have started earlier, and the authors of a paper claim that these zircons show evidence of subduction. Zircons usually contain impurities from their environment, and the argument goes that some zircons contain traces of mica and aluminium, which are both found in granite. They then argue that this came from weathered continental rocks, but this is hardly logical. If there were continental rocks, there had to have been granitic extrusions earlier, so why couldn’t the zircons have formed in those extrusions, i.e. when the first granitic material was being extruded.

The authors then trained an AI analysis of a large number of zircons, and focused on nine of them. My criticism of this is the AI analysis depends on the assumptions put into the program. A typical example was that some zircons are known to have formed in the presence of fresh water, and they concluded that this was a sign that continents, and hence plate tectonics existed at the time. However, when looking at older papers for my ebook “Planetary Formation and Biogenesis” this fresh-water effect was known, and the conclusion then drawn was it was evidence that rain had started and the planet had an atmosphere and weather. What annoys me is the conclusion that was drawn about plate tectonics ignored all the alternatives, and in my opinion, the alternatives are far more likely.

To answer why is Earth the only planet with plate tectonics, my answer is it is the only planet with a large amount of granitic/felsic rock. The reason why is outlined in the ebook above, but basically it depends on the temperature sequence of the accretion disk. As to when did plate tectonics start, we don’t know, but it might have been later than many think. The reason for saying that is there was a great overturn of the surface of the Earth about 2.8 – 3 billion years ago that incidentally made life difficult for anaerobes that needed nickel. The new surface was relatively nickel depleted, and this made the way open for new evolutionary changes that ed to photosynthesis and us.

Τhe RΝΑ World

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Every now and again, something turns up that makes one feel good. In my most recent case it was a book review. No, not one of my books, but one in Nature (vol 632, pp 250-251) on RNA. The Nobel prize winner, Thomas Cech describes RNA as “Folding into origami-like shapes, it can pull off wild stunts that make its genetic parent, DNA, look like a one-trick pony.” This is in his book The Catalyst that is being reviewed. Not exactly a stunt, messenger RNA is used as a template to code protein. That is a perfectly acceptable thing to do, so what are these stunts?

The first one was that genes in plants, fungi and animals are fragmented and contain seemingly nonsensical internal sequences, called introns, that are cut out  of transcripts before messenger RNA is translated into protein. This was a huge surprise; who would have predicted the gene sequence did not correspond precisely to the protein sequence it must encode? Even more interesting, the catalyst that chopped out these introns was made of RNA strands. Here we have a molecule that edits another molecule made of the same components,

The review then proceeds to cover other aspects of RNA, including the messenger RNA that was used for the Covid vaccines, and RNA that can cut and destroy the DNA of invading viruses. Cech also mentions the mysterious “long noncoding RNAs”, hundreds of thousands of which are apparently produced at low levels in human tissues. What is interesting is that fewer are produced in simpler organisms, and given that RNA can destroy RNA, it implies that these strands actually do something relevant. What, as yet we don’t know. More work to do.

However, back to my interest, and that is the proposition that life started with RNA. As the Nature article states, there are two key requirements for life: a molecule must be able to store genetic information, and to reproduce. RNA can clearly do the first, but to do the second, it must have a catalyst available. As noted, RNA is a catalyst that can edit itself. Protein enzymes are much better at catalysing things but enzymes work by a protein structure taking in a molecule that it can fit with (the so-called “lock and key mechanism”) do what it has to do, which involves a further mechanism that is irrelevant here, then having carried out the reaction, it spits out the product and goes onto the next. Because of the shape selectivity, we need a huge number of enzymes to do everything. RNA strands work by folding over themselves and selecting a sequence of nucleobases to do whatever. The early advantage of a ribozyme is it can fold in various places and carry out different catalytic activities. The catalysis is not as strong as enzymes, but when life is getting started anything is advantageous.

The reason I think life started with RNA strands is this. The strands can edit themselves, and in particular, the strands get protected if they for a helix. This is because the scission of the strand starts with an attack on the hydroxyl at then 2-position of the ribose. If it can form a helix, that position is shielded by the next strand’s phosphate ester. This has an important consequence. As I outline in my ebook “Planetary Formation and Biogenesis” the ribose will come in two optical forms, like a left handed and right handed gloves. A helix can only form if the same form of ribose is used consistently. If the wrong form is chosen, that form sticks out, asking to be cut out. I believe this is how homochirality evolved. One form predominated and from its catalytic behaviour it favoured one optical form for proteins, everything.

If you accept that, then we can see where life might evolve. To make RNA strands, all you have to do is put nucleotides into a vesicle (basically, a hydrocarbon or fat-like material with a detergent) and put them onto a rock where water can splash. Experiments get strands up to 300 units in one day. You need 40 units to get catalysis, so there is plenty of choice. The next problem is how to get the nucleotides. There is only one experiment that ever made these under plausible conditions (i.e. what could have happened in a pond). That involved sunlight acting on a nucleobase, ribose and phosphate. Then problem here is to get ribose. This is a sugar, but in general sugar syntheses you get virtually no ribose, and that is because it has a relatively high energy. In my opinion, there is only one practical way to get this, and that is in the presence of silica dissolved in the water, which in turn really only arises around fumaroles. The ancient fumaroles would also have the materials to make the vesicles, so I conclude that life had to start around a silicate-rich fumarole. That, in turn, may well require the fumarole to be in granitic/felsic rock, which actually means Earth had exactly the right conditions. More details in the ebook, which is available at most ebook outlets. The good news for me was that everything a Novel prize winner said about his specialty was required by my theory. See why I felt good?

Failure of Science Publishing

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Modern science relies on the publication of research results, but the question then is, is what is published valid or is it rubbish? This is supposed to be sorted by peer review, that is, before the paper gets to be viewed by the public, peers, nominally experts, review the paper and assess whether it should be published. That may seem fairly straightforward, but  recent paper (https://www.firstprinciples.com/article/is-peer-review-failing-its-peer-review) claims everything is falling apart. Problems include “the publish-or-perish mentality, chatbot ghostwriting, predatory journals, plagiarism, an overload of papers, a shortage of reviewers, and weak incentives to attract and retain reviewers.”

Dealing with the first one first, this problem is clear. Academics get their rewards through the number of publications they have. If they want to get more research funding, they need a list of publications. Since nobody relevant to giving the money reads these to evaluate them, numbers count. Some seem to publish, then check them. Apparently in 2023 more than 10,000 research papers were retracted, while nineteen academic journals closed after being inundated with a barrage of fake research. This is where the predatory journals come in. If there are journals that will publish anything to make money, rubbish gets published. Apparently one scientist holds the dubious record of 213 retractions!

The article assigns the blame for this to poor peer review, but I think that is wrong. I have done a tolerable amount of peer review in my time, and the first thing to note is that if the scientist claims he did x and got the result y, you have to believe him or her. The reviewer cannot repeat the work, in part because of the time taken, and in part because he/she will not have the materials or specialized equipment. Sometimes you see an error; I once rejected a paper because the spectrum provided could not possibly have come from what the author claimed he had. But that is rare. The reviewer can look and see if the methods were appropriate and check any maths but basically the results have to be accepted unless they are too bizarre. All the reviewer can really do is check that the conclusions come reasonably from the results. Unfortunately, all too often the fraudulent submission will know what the current paradigm expects, and will deliver that.

So how to fix this situation? The article suggests paying the reviewers, making reviewing a requirement for employment, and so on, but I disagree. The basic problem is money so focus attention there. If the scientist keeps making retractions, the work was poor. Salary increases, research funding, prizes, etc, should be dependent on a very few papers nominated by the scientist, and in principle should be evaluated by experts. To some extent, this is managed by citations, but that is so easily gamed. I have seen a number of papers with up to fifty authors, and the same fifty turn up on many papers with then order of names changed, and they always cite every paper from the cartel. Apparently there are brokerages  that will sell the right to have a name on a paper!

All very bad, but there is another elephant in the room. Journals want to be ranked number one. The net result is that editors do not want something published that does not fit with the current thinking. Their argument is that if it is all that good, someone will publish it, but they do not want to contaminate their reputation. Accordingly, editors go out of their way to reject such papers. Further, so-called peer reviewers do not want to accept papers that contradict their work. Such rejections are seldom made on the grounds of finding something wrong in the paper; merely the reviewer did not like it. The problem now is that people in power criticising peer review are really wanting the paper to be tidy confirmation of their beliefs. The problem with this is there is no scientific debate because minority views are excluded, and this risks failure to recognize the truth. Our ability to advance can be retarded by just a few individuals in key positions more interested in their own status than the truth. Is that what we want?

Bronze Age Economics

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A recent paper in Nature Human Behaviour (https://doi.org/10.1038/s41562-024-01926-4) looks at human behaviour in Europe during the period of 2300 – 800 BCE, which roughly corresponds to the Bronze Age. The purpose of the paper was to propose that consumption patterns of the time can be explained by standard economic theory. The argument is that random behaviour cannot explain the archaeological data while modern economic theory best fits it. What we know of the period is that there was considerable production and trade in important commodities, such as copper, amber, tin, wool, pottery, and salt and these were consistently in high demand. Further, regional locales appear to have specialized in single commodities for export. That is not entirely surprising, since bronze was extremely important for making metal tools, yet the components seldom occurred in the same place. Much of the copper came from Cyprus, where originally it was partly found as the metal, surrounded by the blue-green carbonate. However, it was also found elsewhere, and apparently lumps of copper metal were able to be picked up on Crete. It is speculated that the smelting of the ore was discovered by having a fire over some malachite, when copper was subsequently found in the ashes. Smallish deposits of copper ore were found over Europe, and could be recognized by their green colour. Bronze is an alloy of copper and tin, and cassiterite (the dioxide) was probably the main source of tin. Cassiterite is found in granite, but it is harder, denser, and more chemically resistant. It often accumulates in alluvial channels, and being dark purple or black it is easily recognized. Apparently, tin was first mined in Europe around 2,500 BC on the modern border of Germany and the Czech republic, but it is rare and most came from the Iberian Peninsula, Brittany and Cornwall. Cornwall was probably the major source for central and northern Europe. The major sources of the components of bronze came from opposite sides of Europe, therefore there was substantial trade quite early, and definitely around 2000 BC.

In some places, mines went quite deep into the ground, but often they were not very broad, and many of the branches were of a size indicating that children may well have been the miners. However, to maintain a sizeable mine, which was needed after all the ores that could be easily picked up were gone, required serious organization. This probably also involved slaves, and this was organized by a few of the very wealthy. Archaeology indicates that the few elites unilaterally controlled production and trade, and the ordinary people did the producing. However, there is a problem in that we have very little information about the non-elites, at least in Europe. What we find is that production greatly exceeded consumption, and it was considered that the production was for display, to assert the riches of the elite, but there is another option, namely there were few of the very rich transactions, but there were  many moderate transactions. That raises a further question: how did the ancients sell and purchase things? We use money, but what is money?

Before we try to answer that, we note that in the Bronze Age in Europe, it was common practice to deposit hoards of metalwork in the ground. Sometimes there were many different objects, sometimes the same such as tens of axes of the same form. Why was that done? An intentional removal of valuable goods to lessen wealth inequalities? Or scrap put aside for future use?

What the authors of the paper found was that a form of standardization of the bronze objects, and of pottery, occurred across the Bronze Age world. Certain distinct designs emerged such as daggers or pottery vessels where there was no obvious reason for the standardization. In some cases objects were similar in shape and weight, but in different regions had somewhat different uses. Archaeologists believe the reason for this standardization was the growing interest in long-distance travel. When you run into people with a different language, similar clothing and similar tools makes it easier to communicate and trade. But it also suggests the beginning of money. You want to trade, but you have wool and they have tin. How do you trade? You use the bronze as a currency. Each party knows so many beads to a small dagger, so many large daggers to an axe head, and so on.

That interpretation puts money as a medium of exchange, but some economists consider money as a medium of account, to keep track of socially important activities such as gifts, debts, tributes, etc. In my ignorant way of looking at things, I see no reason why it cannot do both. However, it may be that this paper overlooks some things, namely quality of the  article. There are written texts from around 2000 BC; as an example, what remains of the library of Shugli I. We think of bronze as an alloy of copper and tin, but antimony, lead, and other metals were sometimes included for special properties. The texts indicate that the smiths of Sumer did it by weight, although I gather our ability to translate Sumerian is very limited unless we have a corresponding text in Akkadian. A further problem is the Sumerian tablets tend to be broken, so key bits are missing. Nevertheless this opens up a genuine opportunity for further research. Sometime, maybe, someone will pick up a key clay tablet that can be translated. What we do know, though, is Sumer had a well-accounted economy, and there are many tablets that tell how much of this was stored, and how much of that used. They had to have an economy better than random trading.