Monday, April 24, 2017

Water Planets

It is relatively easy to compare the mass of the atmospheres of Venus and Earth and ask why is the atmosphere of Venus so much more massive than that of Earth. A simple answer, that it came from some peculiarity of the formation of the planets, allows much speculation, but there are other ways of looking at the question. Earth has an ocean, Venus does not. The comparison of the surface fluids of Earth and Venus goes the other way. The surface fluid mass on Earth is about three times that of Venus. So, perhaps the correct question might be: “Why is the surface fluid mass of Earth so much larger than that of Venus?” The speculative answers as to where the missing atmosphere of Earth is would be no longer applicable.

If the mean surface temperature of Earth were quickly to go up, not to that of Venus, but something high enough so that the whole surface was above the boiling point of water, then the mass of the atmosphere of Earth would be about three times that of Venus, instead of a small percentage. Venus’ atmosphere is almost all carbon dioxide and nitrogen, and Earth’s would be almost all water. The perspective changes. Instead of asking about the mass difference of the atmosphere’s, the most striking question is about the chemical compositions. Where did all the carbon dioxide go from Earth’s atmosphere, and where did all of Venus’ water go? The two planets formed out of the same original cloud of gas, flattened into a ring and rotating about the newly forming sun. They aren’t all that different in distance from the center of the solar system. They aren’t very different in mass. What caused this?

If we want to understand upon which planets life could form, and where it might evolve into star-faring aliens, it would be certainly important to understand how an atmosphere that could support life would form, and how it would transform over the lifetime of the planet. It is apparently much more complicated than might be first imagined.

Suppose the early cloud that formed the inner planets had a slightly different composition, with less of a percentage of heavier elements, those that form the huge core of a planet, and more of a percentage of lighter elements, which might form an atmosphere. If this happened, there might be more of an atmosphere. A solar system with this arrangement might have a rocky planet with more water, among other constituents, in its initial atmosphere, and if the temperature dropped below the boiling point of water, it would condense. Most of the water would condense out of the atmosphere, as the vapor pressure of water is not very high at temperatures well below boiling.

If the mass of water on this alien planet were five times at much as on Earth, and the planet was about the size of Earth, there would be so much water that a mountain range, as high as Everest, would be completely covered. There would be no dry land. This obviously is a major impediment to evolution leading to intelligent aliens. The mass of the oceans are about 0.025% of the mass of the whole planet, and so raising that to 0.125% would do the trick. This is not a large fraction of the mass, meaning there does not seem to be any need for some exotic process to get all the water to the planet. So, one question that pokes up is: “What is the water fraction in distant solar systems?” If it is too large in the region where rocky planets form, we have a water world, with no dry land. Even on a planet which had only a few small islands, like the tips of the Himalayas, it would seem to be unlikely for an intelligent alien species to evolve.

The fraction of mass throughout the universe that is heavier elements is small. It is mostly hydrogen, plus some helium. Somehow this ratio is inverted in the region where rocky planets form. Whatever the totality of processes that do this are, it would seem that a factor of five or ten in the ratio of water is not unlikely. So, water worlds may be common instead of worlds like Earth, where we have almost 30% of the surface dry.

A cloud of gas that is about to form a star and solar system might have enough heavier elements to make rocky planets in it, but how do they get concentrated? If the cloud is rather homogeneous to start, this means that the concentration operation has to get completed either during the initial formation of the central mass or during the time where there is a disk of gas forming into planets or preplanetary clumps. During both of these eras, the gravitational attraction of the protostar causes a migration of heavier elements and molecules toward it. If there is enough time for these twin processes to come to completion, then the ratio of water to heavier elements would reflect the mass of the protostar and the overall composition ratio of the primordial gas cloud. The mass of the protostar is again a reflection of the total mass and volumetric density of the gas cloud. The original composition ratio reflects the history of the cloud, and, according to the current theories of the formation of heavier elements, how many supernovas went off in the vicinity of it during its life in the galaxy.

Both of these go in the same direction. In regions of the galaxy where the density of gas is larger, larger stars would form and more gravitational segregation of heavier elements is possible. In the same region, more supernovas of type II, the most common type in the earlier galaxy, massive stars which explode at a pre-ordained point in their history, should form and contribute heavier elements. Thus, in denser parts of the galaxy there might be dry worlds and in less dense parts, water worlds. In between, worlds which can form alien civilizations that might venture out into interstellar space.

The total mass density of the galaxy is highest in the central core, still high in the bulge, and less in the disk, dropping off as the distance from the galactic center increases. Spiral waves pass through this, changing the density up and down as they pass, but they do not affect the time-averaged density. So, if we want to find alien civilizations, a band of galactic disk about the same distance from the galactic center as Earth is might be a good place to look, if only because that is where partially wet and partially dry rocky planets might be more likely to form. It also means that would be a good place to hunt for planets to colonize, if Earth ever reached that capability and had the desire to do so.

Friday, April 7, 2017

Geothermally Powered Alien Civilizations

Geothermal power has some advantages that should exist, in certain situations, for alien civilizations. It is a fairly simply technology, designed to extract energy from the heat generated inside larger planets from gravitational collapse and impact. Because heat conduction is so slow, this energy can exist in extractable amounts for billions of years. It is one of the few ways of extracting gravitational energy, another being tidal power.

On Earth, it is used very little, as other sources, nuclear, hydroelectric, fossil fuels, wind and even solar usually produce more high-value energy at lower costs. For making electricity, these sources are more efficient. The majority of uses of geothermal power are for heating, as the energy it produces is simply low temperature heat.

The technology just involves drilling down into the Earth and extracting the heat. Usually heat transfer with a liquid is used, as liquids have a higher heat capacity than gases, and conduction is even worse. On Earth, in some areas with volcanic conditions, where hotter mantle material is closer to the surface and forcing more heat upward, it can be readily used. Iceland is everyone’s well-known example. There, by drilling down a half to one and a half kilometers, temperatures in the region of 200 to 400°C, which can produce steam at the bottom of the pipe, which then rises and turns a turbine or serves directly to heat something. Drilling and inserting pipe, even pipes with good insulation, is not difficult compared with other contemporary technology, and so this might be expected to be used by any alien civilization that has the heat source available.

Iceland itself is a volcanic island, and still has volcanic activity on and near it, resulting in, besides volcanoes, hot springs, warm lagoons, and geysers. On an alien planet, with these features widespread, it would be possible for them to dispense with fossil fuels. There is an obvious question as to whether geothermal power could provide the same transitional energy, taking an alien civilization from biomass, flowing water and wind power to nuclear power of the fission and fusion varieties. If that is the case, then this would be a separate line of development, differing significantly from those worlds which might be analogs of Earth’s development.

In an Earth analog developmental path, biomass is used for a long period, until coal is discovered and used as an improved power source. The higher energy density in coal allows machinery to be invented and powered, including mobile machinery. Coal deposits near the surface in England were one factor in why England initiated the industrial revolution here on Earth. In an alien world without coal deposits like this, or something equivalent such as large tar deposits, would it be possible for their technology to develop industry using geothermal power? Geothermal power is not mobile, and so the great advantages of coal in powering locomotives and hauling large quantities of materials, say from mines to processing plants, would not exist. This would mean the population would have to concentrate around the geothermal sites, if they were going to take advantage of the power.

Instead of watermills and windmills, it might be expected that sources of steam would be used to power mills, in some method or other. This might lead to the invention of some machinery, but there would be much less use of it, both because of the lack of mobility but also because of the lack of metals from mining, which on Earth was greatly facilitated by coal and later other fossil fuels. Metals were available as far back as the stone age on Earth, so they would be available on alien planets, if the right ore deposits were available. However, smelting takes advantage of the concentrated heat that can be generated by coal. Blacksmiths from the Roman era and even before used bellows to concentrate heat from hardwood fires and produce iron and steel, but there is a quantitative difference in the amount that can be produced.

With no coal for the first railroads, would there be any industrial revolution on an alien world that depended on geothermal power? Iron would be much more expensive, meaning machinery would be invented much more slowly and would not propagate as fast, meaning that progress would be very much slower than in the rapid pace of Earth’s industrial revolution. Electricity would be invented, but perhaps centuries later. Once electrical machines were invented by alien equivalents of Moritz Jacobi and Werner Siemens, the inventors of the ac and dc motors, and many other equivalents and accessories needed for an electrical power industry, along with generators, transformers and so on, the alien civilization should be able to develop some sort of mobility other than by animals and wood-fired engines. Because this type of transportation is much less efficient than fossil fueled transportation, the rate of progress would remain much slower than we experienced here on Earth.

Slower, but not impossible, is the diagnosis of the various technology steps that a non-fossil fuel world would experience with an abundant source of geothermal power. What kinds of worlds might have this?

There is a relationship between the presence of heat sources just below the surface of a planet and the surface temperature. If it is too hot, life cannot evolve in the same way that it did on Earth. Carbon-based life needs a fairly narrow range of temperatures to exist, and an even narrower one to evolve into multicellular creatures. It is not clear if there is even a narrower range in which large differentiated creatures can exist. So, a planet with a generally hotter core might prevent this. Is it possible that the phenomena that exists in Iceland could exist on an alien planet in many more places, but not so much as to heat the surface by more than a few degrees? Iceland is located on a boundary between two tectonic plates, where molten magma can rise to the surface more easily. Hawaii does the same, but the volume is less there and there are only few places where geothermal energy can be tapped as readily as in Iceland.

Suppose the chemical distribution of elements was somewhat different, and there were less lighter elements and the crust slightly thinner on some planet. The thickness of the planet’s crust cannot be much less than Earth’s, or heat would pass through too fast. Thus, a bit less light elements might do the trick. Then there might be many locations like Iceland, and industrial development could occur, only over millennia rather than centuries.

Another consideration is that there would have to be no fossil fuels available to the civilization, as these would displace any use of geothermal power and more accurately align the development there with that of Earth. The two theories for fossil fuel origination are the biotic one, in which vegetation is buried and becomes heated, transforming the remains into mostly carbon chains, and the abiotic one, in which carbon chains form and chemically separate, just as most other minerals separate into segregated ore bodies. However, it doesn’t have to be that there are no fossil fuels on the planet, but just that they are not available. This could mean no coincidence of shallow burial of coal deposits and alien civilization areas. With the biotic theory of origination of fossil fuels, this does not seem likely on a planet which has enough life to generate eventually intelligent aliens. So this may be the actual show-stopper on the geothermal variant of alien civilization. It certainly needs to be thought through more deeply.

Tuesday, April 4, 2017

Multiple Pathways to Idiocracy

Idiocracy has been bestowed a dictionary definition, meaning, primarily, a government by idiots. In this blog we have been using it in a slightly different way, meaning, a society populated by idiots or at least by people whose genetics, training or education are not sufficient to maintain the society, leading to a regression. It stands to reason that if the population doesn’t have the intelligence to maintain the society, that the governance they would have would be not very bright as well, so the more general definition implies the more specific one. Our use does an injustice to the roots of the language, but there isn’t a substitute.

This blog discusses the routes that might lead to this situation in an alien civilization. Here on Earth we haven’t yet developed any good metrics for intelligence, so the discussion has to be a bit vague on that point, but in general intelligence is used here to mean problem-solving ability. It does not mean formal test-taking ability or its variants, except to the extent that taking tests well can be taken on as a general problem to be solved, and the intelligent alien, who has the ability to solve problems, can figure out what has to be done to allow him/her/it to take tests well and then implement these ideas. However, it an intelligent alien does not choose this task as important, it will not happen, so test-taking ability is far from synonymous with intelligence. Probably in any alien civilization, test-taking ability can be inculcated into an alien without general problem-solving abilities.

For intelligence to occur in any individual alien, there has to be three predecessor events. One is that they must be conceived of with the genetic complement necessary to allow learning problem-solving. The second is that they must receive training which motivates them to do problem-solving. The third is that they must obtain the necessary education to equip them with the intellectual tools necessary for problem-solving. If any one of these fails in the alien civilization, then idiocracy can result.

For any complex skill, there is a distribution of attainments. By complex skill, we mean one that is underpinned by multiple distinct capabilities or attributes. Consider size for aliens. If they are anything like us, and the concept of convergent development implies they would be, there would be multiple genes that dictate what size an individual alien will attain. If, for each of these genes, the population has a distribution of variants, then when put together, a smooth distribution would occur. For any one of the genes, there is simply a percentage for each of the variants, and if there was only this one gene to affect size, the population would be divided into groups according to which variant of the gene they received. If there were multiple genes, and importantly enough, if they were independent, the laws of statistics can be used to show that a Gaussian distribution, often nicknamed a bell curve, must result. It doesn’t matter if the effects of the different genes were different in magnitude, for as long as none of them were responsible for most of the variation, there would be a Gaussian. In the case where one of them contributes, say, 50% of the variation, then there would be a distribution that looked like two Gaussians next to one another, where the spread comes from the genes which contribute small contributions and the difference between the centers of the two distributions comes from the single gene which dominates size.

If there is correlation between the genes that control size, then the distribution would not necessarily be Gaussian, but something else smooth and with a central median and a width, both of which can be measured statistically. This conclusion finally allows the discussion to continue. For a distribution for either of the three necessities for an intelligent alien to arise, genetics, training, and education, there is a median and a width.

In an alien society that is approaching idiocracy, it is possible that the median of either of these three is being lowered and it is alternatively possible that the width of the distribution is being shrunken. The median-lowering effect happens if there is a correlation between reproduction rates and position on the distribution. For genetics, if parents, or whatever predecessors contributes genes to a future generation, with good genes produce less descendants than those with worse genes for intelligence, then the median drops. For training, if parents, or whoever in the society trains young aliens, in successive generations provide less motivational training, then the median drops. For education, if parents, teachers, mentors, or whoever is responsible for education of each younger generation, in successive generations provide poorer education, then the median drops. These represent three distinct pathways to idiocracy.

If the alien society needs very intelligent members to continue to function, as it would in the earlier periods of the civilization before some artificial intelligence was developed to an extent sufficient for it to fill in for a lack in the population, and the width of the distribution of intelligence drops, then the society would again drift into idiocracy. Again, there are three distinct pathways. There could be a reverse correlation in mating, where those with good genes couple with those with worse genes, shrinking the width of this distribution. There could be a negative correlation in the training arena, where those who support proper training are marshalled into allowing and accepting poorer training, and the motivational training becomes more and more uniform and average. And lastly, there could be a negative correlation in the educational arena, where those who could provide proper education are convinced to provide successively poorer education in order to follow some poorly-conceived guidelines or to support some non-educational goals which conflict with the provision of top-notch education.

Thus, we have here at least six pathways to idiocracy which any alien civilization might fall into. How is it possible that an intelligent alien society could make such seemingly obvious and disastrous errors in managing itself? One would be that the lack of a metric means that the falling of capability is not clearly demarcated. Another would be that the society is simply absorbed with other questions and pays very little attention, as a whole society, to the importance of maintaining intelligence in the population. Certainly there are others, and each of the six pathways might be further subdivided as to the mechanisms by which they could occur. As noted elsewhere, idiocracy is a major peril that any alien civilization that achieves affluence, at least in a faction, will face. It could be one of the principal factors explaining why there is no noticeable alien travel in our galaxy, although there are many competitors for that distinction.