Thursday, August 20, 2020

Detecting Alien Civilizations

Aliens haven't visited us as far as we can tell. They also haven't sent us messages that we could recognize. So, we have to peer out into space and look for them. Finding a planet which has oxygen in its atmosphere is regarded as a signature of life, as oxygen likes to bind to the exposed surface material and wouldn't exist in the atmosphere if it is not being replenished by life processes. At least that's how Earth works, and other planets may use this design as well. But oxygen or not, this says nothing about detecting aliens themselves. If they have an advanced civilization, they may be beaming messages in space, but we haven't been invited to join the network, and don't have a clue as to how to fill out the application. So we need to look for them, and then perhaps we might send a signal that says we want to chat. At least we would know where to send the signal. Detecting alien civilizations on a planet is difficult because they likely would not create any signatures on the planet which would be visible at lightyears distances, unless we built some very large telescopes. Even then, seeing some city on the planet's surface is unlikely. Perhaps if they traveled in space they might be detected. Consider the background of the signatures we could look for. If there was a planet like Earth, with life and even worse, weather and geological features and water features and more, all these would make the detection of life with low-resolution telescopes difficult. By low resolution, we do not mean little things like Palomar, but instead telescopes which have only ten to a hundred pixels resolution across the diameter of the exo-planet. That means, we would be seeing, at the best, only things which could stand out at those resolutions. What might they be? Suppose there was a very large city somewhere on the planet. This might be a few kilometers across, compared to the size of the planet, which might be several thousand. This is not going to be visible unless there is some spectral assistance. For example, if one pole of the planet was very cold, at the time we observed it, and the city was warm, we might see one pixel bright in the far infrared, surrounded by black (in infrared) pixels. This would be a good option, except infrared is absorbed by any atmosphere we might expect on a Earth-like planet. Maybe they have a thin atmosphere, very warm cities, and very cold polar areas, and then we might see the city. There is a much better chance to see some warm city on a satellite without atmosphere. If they had, on one of their planets, a moon with no atmosphere, but plenty of minerals and other things that were useful for the aliens, and they built some surface habitation there, it would be easier to see. The habitation would certainly be smaller, but the moon might be, for at least part of its orbit, much colder and not only that, more uniform in temperature. Thus, the detetability of a far infrared signal might be easier, even if the habitation was smaller than a city on the origin planet. So, an alien civilization with interplanetary capability might be easier to detect. There does not even need to be the assumption that the origin planet is in the same solar system. No matter how they get to the cold, cold satellite, the detectability calculation is the same. If, for example, their origin planet was on one star of a binary system, and the satellite they were visiting and colonizing was on the other, they would be detectable. And it certainly does not have to be a satellite. Any small world with no or a thin atmosphere would be just as good for detection. It might be that the future of alien space travel from this particular planet was very practical. Since there might not be any planet similar to their home planet within many light years, they might have decided they were going to go to many of the solar systems near them, within say ten light years, and set up colonies wherever they could be self-supporting. This could mean some good fraction of the solar systems around them will have some colony there. Perhaps a good fraction of these colonies would be detectable. How many colonies might there be? Suppose the universe is generous, and it is possible to set up a self-sustaining colony on a wide variety of smaller planets. Because we don't have any good knowledge of this number, none at all actually, because no one seems to have worked on it, let's assume it is 10%. So, if the average density of solar systems around their origin planet is about one in every 10 light year cube, the average alien civilization should have a colonizable solar system within about 9 or 10 light years. If their ship travels at 1% of the speed of light, it should take them about 1000 years of travel, plus some preparation time, to move to their first colony. If the universe is even more generous, and a self-sustaining colony can build their own starship in a thousand years from the foundation, they can start their second round of travel at 2000 years and arrive at the next planet at 3000 years. If they do two at a time, this means by 3000 years they have seven planets. In 2N-1 thousand years, they have 2 to the Nth – 1 planets. This works out to a million planets in about forty thousand years and a billion in less than sixty. These numbers are not realistic, but just are shown here to explain that covering the galaxy with alien colonies doesn't take that long. They could go much, much slower if they chose, and use up fifty million years colonizing the galaxy. Or whatever. If we want to go looking for alien civilizations, so that we can contact them or sell them our planet or just wish them well, it seems there is a fundamental division in how we choose to do it. The deciding question is: Is star travel possible, for an advanced alien civilization with a solar system full of resources and plenty of time to do anything necessary? If the answer is yes, it seems rather foolish to concentrate on looking for their home world. We want to know where could they have a self-sustaining colony, because there could be a billion of those and only one home world. Bad, bad odds. If the answer is no, then we might first ask: why are we doing this? Every civilization is all isolated in their home solar system, and what possible use could it be to find some other set of prisoners? Commiseration? But if someone could come up with a non-nonsensical, seriously rational and utilitarian, answer, for looking for somebody else's home world, we need to do some fundamental research which seems to be virtually ignored. If you want to find the home world of some aliens, you need to figure out what characteristics of the planet and its star are necessary, and what other conditions there are, such as having a satellite, low eccentricity, large gas giants in the same solar system, axial tilt and so on. A simple temperature of water condition is foolishly simple. We need to find the conditions both for life to originate and then, completely separately, for an intelligent civilization to evolve. That's what this blog is all about, but much more could and should be done.

Sunday, August 16, 2020

Aliens in Binary Star Systems

Can an alien civilization arise in a binary star system? This is not a relevant follow-on question to the principal one: Why haven't aliens visited us recently? It is one that is relevant to the hunt for alien civilizations from Earth, as if they won't come to us, we'll have to go to them. It is important to build some filters to separate out solar systems where aliens might be found, versus ones where they certainly can't have originated. After an alien civilization has mastered interstellar flight, they could go to any solar system they want, which makes the hunt more challenging, but if we are trying to find ones where they could have originated and specifically not where they might have seeded themselves, we can come up with some sharper criteria. So, could there be an alien home world in a binary star system? We don't want to spend precious telescope time on the impossibilities. First off, even if a binary or multiple solar system has a star which is suitable for origination, a G star like our sun, or sometime close to it, an F or a K star, that doesn't mean there aren't difficulties for life origination. When we see a binary, a physical binary of course not just a visual binary, if the companion star, or one of the companion stars in a multiple system, is a large star, we know that the age of the solar system is too young to have aliens, as these stars do not live very long. For example, even a mid-class F star, like an F5, doesn't last long enough for life, at least if evolution is as slow there as it was on Earth. Thus, both stars must be smaller than about a F7. If the other star is a white dwarf, this is also a bad sign, as white dwarfs are the end-stage of stellar evolution. It means that at some time in the past, they went through the red giant stage, then ejected most of their matter and collapsed to a white dwarf. A planet around a binary companion of this process would likely experience severe disruption, and any life that had originated on that planet would be either terminated or put through some severe extinction processes. While somehow life might re-evolve after this if the white dwarf process had concluded billions of years in the past, it would seem more fruitful to look at binary systems which have not endured the end-stage of stellar life. The next requirement is for stable planetary orbits. Three classes of orbits can exist in a binary system. One is where the two stars are close together, and the planet away from the pair of them by many times the inter-star radius. If you were such a the planet, you would see the two stars at once, circling each other. A second class is one where the planets are around one of the stars, and the other star is far distant beyond any planetary radii. The third is everything else. Your imagination can run wild here, with orbits making figure eight loops or some sort of modified oval around both of them. Clearly the discriminating ratio is the inter-star distance divided by the planetary radius, or for complicated orbuts, the mean distance over a long period of time from the planet to either of the two stars. If this ratio is very small, you have type one, very large, type two, mid-sized, type three. So far, it does not seem there has been a Kepler for type three orbits, and so we don't have a nice classification of them, along with the limits for stability. We hardly have the limits of stability for non-binary solar systems, so this is hardly unexpected. Type three orbits are better left ignored for now, although some computations could be done fairly easily to search to see if there are any weird orbits that are stable in this category. Type one orbits have a different problem. With two stars circling each other instead of a single star, a planet will fell much more of a tidal pull. In other words, two close co-orbiting stars will tend to transfer angular momentum out to the planet much quicker than a single star could. Since angular momentum increases with radius, this means the planets would be driven outward and eventually dispersed. Maybe that would be billions of years, but for life to evolve, a planet needs to be in a near constant orbit for these billions of years. The good-for-life situation is that a stars stays quiet and constant for eons and the planet is in a stable orbit. Alternatively, the planet could slowly drift outwards as the star becomes hotter with age; both of these processes happen quite slowly and fortunately go in the right direction. This matching is not something that would likely work with a type one orbit however. This means that we should look for planets hovering close to the star, meaning also that binaries of interest must be long-period binaries, the hardest to detect. In other words, if we already know a star is part of binary star, it is a poor candidate for an origin-of-life source because we can only identify short-period binaries with our current telescopes. Earth's astronomers have not identified many binary star systems yet, compared to the number of nearby stars, but somehow an estimate has been made that a third or half of all stars are in a binary system. Hopefully for the existence of aliens, these are mostly very distant binary systems. To use Earth as an example, we might have a binary companion star, maybe another F class, at 50 thousand AU, nearly a light year out, and it would not have prevented life from evolving here. At five thousand AU, perhaps it would have, and there is some boundary of influence that remains to be calculated, once we actually figure out how life originated, that is. To do a better job at identifying binary star systems in the neighborhood of our sun, we need bigger telescopes. Perhaps a verey large one at an Earth Lagrangian point could be used to develop btter parallax readings on nearby stars to get their distances and proper motions more exactly. One out at a Saturn Lagrangian point would be even better. There is little hope in simply watching far-separated stars to see if they circle on another. The type of orbits we are looking for, where a planet can be safe to originate life, means the two stars circle with orbital periods of the order of a million years. This is the limit of permanent connection. Stars cannot be in binaries at several light years distance from one another, as other passing stars will exert too much influence and destroy the orbital containment. So, distances of a tenth to a half of a light year are what to look for in a binary system where aliens can peacefully live and develop their civilization and hopefully star travel.

Friday, August 14, 2020

Nearby Black Holes

Currently, it is very hard for Earth astronomers to detect black holes. Black holes are neutron stars which have enough mass to generate a Schwarzschild sphere around them. Neutron stars are stars which have a density like that of an atomic nucleus, except there are simply neutrons there instead of a mixture of neutrons and protons. Neutron stars are not black, meaning some light can get out of them, but for larger ones, it is not much. Consider a neutron star just a little lighter than a black hole. Light emitted at the surface will fall back to the surface unless it is going directly up. In this vertical case, it gets reddened an extreme amount, making it hard to be collected. A slightly less mass neutron star would have a wider cone of light which could escape from the surface, but still it would be strongly reddened and therefore hard to detect. If a neutron star is adding mass, by infall for example, its emission cone gets narrower and narrower, and the photons that do escape get redder and redder. The limit is reached when the cone goes to zero, and then even vertical photons fall back to the surface of the neutron sphere. The highest point a photon can get is called the Schwarzschild sphere of a black hole. Neutron stars are terribly difficult to directly detect for another reason. Any photon which is created even a few neutron radii below the surface is likely to be absorbed before it gets to the surface, so not only does light-bending make them invisible, so does the lack of emission sources anywhere but in the thinnest layer of the surface. Exceptions are those neutron stars which have intense magnetic fields and emit radiation at the poles, and others which rotate rapidly and radiate pulses due to some interaction of the magnetic field and surrounding matter. How many of these mostly undetectable black holes and neutron stars might there be? The only mechanism found so far for generating them is the burn-out of large stars, ranging from 10 to 25 solar masses for neutron stars and more for black holes. A simple table of such stars, showing their lifetimes divided into the age of the galaxy can produce an estimate. One can assume that the number density of these large stars has been the same during the life of the galaxy, or something else that would be higher, as there was earlier more gas to form large stars. This gives a number of the order of a billion neutron stars might exist now, but since they are almost undetectable, the estimate could be far off. Black holes form either from the collapse of even larger stars, or from a neutron star which collects more mass. How many of them exist in the Milky Way? If most neutron stars wind up as black holes, the number could be something like a billion. If the production of large stars in the Milky Way when it was younger was more intense, there might be ten times that. To get some casual estimates, this number can be compared with the number of stars in the Milky Way, but regrettably, that number is quite uncertain as well. Perhaps there are a hundred billion. If the density of neutron stars and black holes together is a tenth that of stars, and the density ratio holds in our part of the galaxy, it means that there might be a black hole or neutron star something like five to ten light years from many solar systems. In some cases, one might be closer than the nearest star. Neutron stars have about the same mass as the sun, and black holes start at perhaps twice the mass of the sun. This means that if one were nearby to a solar system where there lived an advanced civilization, it could be fairly close, perhaps closer than a half lightyear, and still be hardly detectable. If we consider the Earth as an example, if there was a three solar mass black hole at 30000 Astronomical Units out from the sun, it would not affect the solar system much at all, and therefore not be indirectly detectable. Gravitational pull from the black hole would be of the order of a few billionths of that of the sun on the Earth, and not much more on the outer planets. This radius is out in the Oort Belt, whose existence is somewhat controversial, as nothing in the Oort Belt has ever been detected. Its existence is surmised as the source of long-period comets which come hurtling in toward the sun from time to time. A black hole out there could serve as the instigator of the comets as much as having a hidden planet there or just having one icy blob interact with another to change the comet's orbit to an extremely elliptic one that passes near the sun. What would it mean to an alien civilization to have a neutron star or black hole a half-light year from its sun? These objects would certainly be detectable with huge telescopes for the civilization, just as they will be from Earth as soon as we start building them. There are really two different situations here. One is that if the black hole (or neutron star) has planets, it would be a very convenient location for an initial starship to head to. But can a black hole (or neutron star) have planets? Large stars are just as likely or even more likely to have planets than ordinary-sized stars, so just before the star starts its supernova process, the planets will be there. They might be the size of Earth and rocky, or gas giants, or icy mid-sized planets or any other combination. When a supernova goes off, a tremendous amount of mass and energy is emited from the star, and it comes crashing into the planet. What happens? In the first stage of the process, for a rocky planet, the side of the planet facing the star turns incandescent, increasing the pressure almost instantaneously, which starts to blast mass away from itself, towards the star. This process, explosive ablation, builds a barrier between the planet and the supernova so that the ablated material absorbs some of the radiated energy. If some gets through, the ablation process gets more intense, and larger quantities are blown into the barrier. This is a feedback effect, and if the planet is big enough, it might stop itself from being totally vaporized, so that when the supernova explosion process ends, what is left can reform into a planet. It will be in a more elliptic orbit, but that might circularize over some millions of orbits. A gas giant or an icy semi-giant will also have an equivalent process to explosive ablation, but the atmosphere will be torn off and if there is a core, it might be exposed. Exactly what is left depends on the strength of the supernova, the mass of the planet, its initial radius, and a whole lot of very interesting physics. At least some possibility of a planet surviving a supernova exists. Alternatively, a black hole could capture a rogue planet that came near enough to it. Too near, and the black hole would eat it, too far and the planet would continue on past, but at some intermediate range of closest distance, it could get captured. Since the estimate of rogue planets in the Milky Way exceeds the number of stars, this is not terribly unlikely. Thus, if the alien civilization was quite fortunate, it might have a black star or neutron star reasonably nearby and there might also be a solar system of sorts there as well. It seems beyond doubt to assume they would make that their first destination after they had explored their own solar system's planets, and any solar system on a binary companion to their own star. This would be a learning experience and might eliminate the need for a very chancy shot at a solar system a hundred or two lightyears away. The other situation is where there are no planets, and then the alien civilization would have to build a observatory to orbit the black hole, which is a large undertaking. They might prefer to go to the nearest attractive solar system.

Wednesday, June 17, 2020

Heavy Elements in Galaxies

One question relating to the geological separation of useful mineral ores on exo-planets, something critical for an alien species to develop technology and socially evolve into an alien civilization, is about the distribution of heavy elements around the Milky Way. If a exo-solar system evolves from a gas cloud with very little heavy elements, above neon for example, it might evolve life on a suitable origin planet in that solar system, but the aliens, after becoming intelligent, wouldn't find the metals they need to go from a stone age to a bronze age, and they would never develop an advanced civilization. Thus, in order for us to have visitors from a particular exo-solar system, it has to have formed out of the same set of materials in the gas cloud, approximately, as Earth did, or maybe one which was richer in heavy elements.

These heavy elements are thought to be produced in supernovas, of which there are multiple kinds. Stars are nuclear ovens, gaining energy from nuclear fusion, which produces the elements above helium. Larger stars burn nuclei up to the nucleus with the least energy per nucleon, iron-56, but the kinetic process of showering nucleons into nuclei produces a wide distribution, centered around iron. Other phenomena produce heavy elements, and may produce a different distribution than burning in stellar cores. One example is the merger of two stars, in particular, neutron stars. So there can possibly be multiple sources of heavy elements, but they all involve stellar fusion processes or stellar disruption processes.

There are very few observable supernova in our galaxy, and probably very few stellar mergers as well, down in the number of a few per century. This rate cannot have produced all the heavy elements we see today, so the rate of production must have been much higher in the early galaxy.

Galaxies may form from the condensation of gas clouds of appropriate size, and as they condense, there are fluctuations in density leading to places where individual stars can form. As the enormous, galaxy-sized gas cloud condenses, if the density is relatively large compared to our current location, large stars will form as opposed to small ones. Large stars invariably turn into supernovas, and the largest of them might even totally explode, rather than just the outer layers exploding. The center of the star will be almost all heavy elements, with iron as the center of the distribution of elements, and larger stars may be more likely to have completed more of the fusion, so the central iron-dominated core will be a larger fraction of the total stellar mass.

This means that during the first phase of galactic evolution, long before the disk evolves to carry away the angular momentum of the cloud, the gas will be large homogeneous, or at least homogenous in spheroidal layers. The disk will form from the outermost layers of the galactic gas cloud, and thus we might expect that the disk will be fairly homogeneous with respect to the amount of heavy metals that exist in the disk and spiral arms. Thus, to a very coarse first assessment, solar systems close to ours might be expected to have the same distribution of isotopes and therefore elements. So, unless we want to think of stellar travelers coming from distant parts of the galaxy, the initial fund of elements should be sufficient on origin-type planets to allow any civilization which develops to get past the stone age, and move onward to industrial development and past that, provided that the geological separation processes on their exo-planet were sufficient to allow the useful elements to collect into bubbles within the molten core, and drift out to the crust and condense there into a solid.

The crust of an approximately Earth-sized planet does not have to be stable. Lying just underneath it is a hot molten layer, which may be in motion relative to the crust. Why? Because tidal pulls on the crust and on the molten layer are different, and induce a differential motion. Tide does not affect different materials the same, and a molten layer might move differently underneath a frozen crust. The crust might be flexed, and molten material leak upward, in what is called a basalt flood, if it is large and spread over an area, or a volcano, if the leak is confined to just a crack in the crust.

It would seem that a moon, during its early days of being much closer to the planet, had yet another task to perform that would be useful to an alien species which would arise much, much later. It causes a mixing of materials between the upper part of the below crust layers and the crust layers. If the two of these are each filled with different ores, the upper surface, where alien miners might get to it, would have an even better mixture of elements than there would be on a planet without a large moon initially close into the planet.

Often solid materials are more dense that liquid ones, and thus the crust, if it breaks into fragments, might be denser than the upper part of the layer below it, which might be called the mantle as it is on Earth. Then any cracking of the crust would allow part of it to sink down slighly, providing an opening for mantle materials to move upwards, and cool. There would be a balance between these materials cooling and becoming more dense, and the pressure inherent in the mantle both pressing them upward and condensing them to higher density.

The iron core would be largely elemental, but the condensing minerals would be combinations of metals and anions of various kinds, as there would be plenty of these elements in the initial cloud as well. The proto-planet would have elemental carbon and oxygen, which might combine to form a carbonate with some metal. And so on for all the other types of compounds found in ores. It might even be that the gas cloud, which has some percentage of dust mixed in it, already has some beginning compounds, and these partially remain intact during all the condensation and heating phase of planetary formation.

It would seem that the best way to explore our local galactic neighborhood for planets containing life and also alien civilizations would be to improve our telescopes and other detectors, and look for an Earth sized planet, located in a stable orbit relative to the other planets, and with a large moon locked into a orbit around it. Of course the stable orbit must be in the liquid water zone, have some axial tilt, and not be in too elliptical an orbit, which may be implied by the stability of the orbit, unless there were no large planets in the solar system.

This tangentially raises another interesting question for our exo-planet astronomers: are there any solar systems which have only one planet? Or is this an impossibility due to some feature of the mechanism of planetary formation? We on Earth have detected only one planet in most of the solar systems we have so far discovered, but that is not the same thing. It would be fascinating to find out there were many like this, with one planet only. This revelation would mean that we have less guidance from our home solar system toward understanding what goes on in other ones.

Monday, June 15, 2020

Futurology and Alienology

Futurology is a name coined back a half-century ago, meaning the science of predicting the future. It may be obsolete now, but the idea of predicting the future has been around since man first figured out the difference between the past and the future, during the beginning of intelligence. It was always a way to get personal benefits. If you could talk to the gods and get the future from them, you could command a good position in your clan. If you were an erudite historian in the Middle Ages, you could talk about all the historical precedents for the present time, and what history says will happen again. In the fifties, it was chic to use statistics and various listing techniques to develop some semblance of a science. It was also common to assume that the average impression of lots of people was better than the insights of any one of them, and so survey techniques became common, with questions all about what the future might have. None of this made any sense, but it did make some good salaries. Back then computers were somewhat novel, and the idea of modeling and then simulation of something became an obvious outgrowth of them. There was little concept of the individualistic nature of a model, and it was thought that there was something intrinsic to some part of nature or society that would appear in models. Even now it is not at all understood that a good modeler can make almost any output come out of his model of whatever it is you wanted modeled.

Alienology is a name used in this blog for the attempt to use other types of scientific methods to analyze what parts of the development of an intelligent alien species were mandatory and which ones were stochastic. It may have been used elsewhere for other purposes, maybe cataloging movie aliens or designing creatures or documenting what some impressionable individuals have reported about their purported contacts with aliens, or whatever. One of the motivations of alienology, as presented in this blog, is to answer the question of why aliens haven't visited us. This question has been around since someone first conceived of the idea that the stars in the sky might signify other worlds like our, complete with people of some sort or another. Buddha included this concept in his teachings, back two and a half millennia ago, so the question is a very, very old one. Buddha's writings were recorded because he was revered as a great teacher, but all those other people from two or three or more millennia ago who said the same thing did not have their comments remembered. The question is more than old enough to have been answered already, but like many other subjects, there wasn't enough science back then, up to a century ago or so, to provide any reasonable way to credibly answer it. Now there may be.

The techniques used for alienology have been described in several other posts, except for one. That is morphology, which was invented by Swiss-Czech/Bulgarian scientist Fritz Zwicky, who also is responsible for many things known by children everywhere today, such as supernovas and jet engines. He used his technique of morphology for these inventions, and wrote a book about it. Morphology is simply the idea of listing all the possibilities for any option, in a scientific concept or engineering invention, and investigating them one by one until the one that is best emerges. It is methodological investigation, and of course has some difficulties, such as how to you define the criteria or attributes of the object you are going to list possibilities for. This involves a way to categorize objects, or rather, everything, on multiple levels.

This becomes an almost intuitive tool for those embracing it, and alienology does this, by questioning assumptions and asking what other alternatives might there be, and then investigating them equally, with an open mind. It is the opposite of learning the best answers for questions, and then building on them, and instead is more of a tearing down of best answers than building on them; then these best answers might occasionally get replaced with something different. The novel theory of the origin of life introduced in this blog is the result of this process, and the concept of swarms of black holes is another. There are indubitably many others buried in the blog. Morphology is one of the principle tools of alienology, along with technological determinism, the concept of asymptotic technology, and others.

This is all well and good, but what about futurology? Predicting the future of mankind would be a great blessing, but it is largely impossible, as there are so many stochastic events which affect the detailed course of future history. However, alienology states that the broadest flows of any alien civilization, of which Earth is an example to any other alien species, have a discernable outline. Thus, what happens next year or next decade cannot be aided by any derivation within alienology, but perhaps what happens next century or next millennia might be, or following morphology, there might be a list of possibilities which are exhaustive.

Mankind up to now has had very little interest in the far future, so the importance of anything alienology can say to futurology might be very tiny. You can't invest for stocks based on what happens three hundred years from now. You can't prepare for social change if you can only figure out what the social system might be a thousand years from now. So, as a practical matter, alienology is useless. There is no magic key that will help futurology become more relevant and less foolish.

Are there any benefits at all for life on Earth from alienology, except to answer the question of where aliens are and why haven't they showed up here yet? There are, but they are subtle. If they help a few of mankind's deeper thinkers spend some time on questions of the far future, instead of only the near future, then perhaps some improvement in the direction humanity takes toward that future might be obtained. Mankind seems to care not a whit about their decendents a thousand years from now, and perhaps that might be changed so that some planning is done with them in mind.

Sunday, June 14, 2020

War and Technology Development

We use the word 'war' in alien civilizations to mean the wanton destruction of alien persons and property for the purpose of having one faction, likely one region on the planet, dominate to some extent another faction. It would be possible to have physical war and economic war, both done for the same reason, but with different means: one based on whatever weapons were available on the planet and the other on whatever financial arrangements were used on the planet. Mostly we discuss physical war here.

One question is whether war would be inevitable on every alien planet where the civilization reaches or exceeds the industrial stage of technology development. Another question is whether this is positive or negative toward the final result of being able to build starships and visit other solar systems, or at least seed them or do something there.

War on Earth has occurred since history was started, and likely long before. The scale has increased with technology improvement, but the idea of one group killing and destroying another has likely been around since before intelligence evolved. There are Earth predators who defend their hunting territory from predators of the same and similar species, and if an alien society began the climb up in intelligence, it would likely become a predator of some sort. Other motivations might exist among early alien species as well, involving mating or some outgrowth of the mating rivalry that exists in very many Earth species.

The growth of intelligence does not happen unless there is some benefit to the species for having it, and that means, in early species, more food most likely, or preferred shelter or something else. More food means becoming more of an omnivore, and one of the earliest technologies, fire, enabled a wider variety of food. So predatory behavior is likely and an outgrowth into intraspecies battles is not a wide step for evolution, social and genetic, to take. This expands to war between larger and larger groups. Control of larger groups is a likely outgrowth of control of a clan or tribe, and so war arises.

Does it persist, or might the alien civilization conclude there is little benefit to it and declare a never-ending truce between all factions? This is, of course, not a real question but a sham one, as it assumes that civilizations make decisions and conclusions, when actually it is individuals who make decisions with whatever brain they have evolved. The real question is, among those who control factions on an alien exo-planet with a civilization of some level, do they decide to direct their members into a war or not? Some decades ago, it was fashionable to think of the reasons for war and do statistics on various aspects of Earth factions to try and determine some insights. Now, that is seen to be foolish, as it ignores the mechanism by which wars are initiated.

Let's make a list. An individual alien might want his faction to go to war against another particular one for some emotional cause. If war is itself the end, it might be that the individual grew up as a bully, or the equivalent among aliens, and simply enjoys this concept and draws pleasure from doing it on a large scale. Alternately, it might be that the individual grew up in an environment which favored physical fighting among young aliens, and so the idea would be to have a war against some other roughly equivalently powered faction, meaning region. These are the 'bully' and 'boxer' motivations. One favors decidedly weaker opponents and the other, roughly equivalent ones.

The other side of this is that war might be only a means to some other personal end for a specific decision-maker, such as personal wealth, revenge against some individual high up in another faction because of some unforgettable insult, hatred against another faction because their policies do not please the decision-maker, gaining advantages by means of the processes involved in war for the individual or some subgroup within his faction that he is a member of and wishes to have excel over other subgroups within his faction, secret hatred for his own faction and a desire to see it weakened by the war process, and so on. This list is much more extensive than the war as an end list, but the point is that there are myriad reasons that a particular individual might wish for a war against a chosen opponent.

Would these lists be empty on an alien planet? It sounds impossible, given the evolutionary sequence that it takes for a species to become intellgent tool-users and problem-solvers. So, our simplistic analysis indicates that there would likely be a period of development, starting early and ending somewhere around the time when neurology is well understood and politics stops being controversial and becomes a search for effectiveness.

The second question is, is this warring positive or negative for the alien civilization for reaching the travel-to-the-stars era of their existence? Time passes in the alien civilation, and technology develops, moving it forward from era to era, but it also involves, in later stages, the consumption of easily available resources. Technology enables more resources to be available, and provides more energy to be consumed in the process of obtaining and using them. Resource use goes at a rate related to population growth and the achievement of efficiency in using them, as well as the living standard averaged over the planet. If technology development goes very slowly, resources might become exhausted, to the existing accessibility limit, before new technology is available to increase the amount accessible. This means the civilization burns out and collapses to a level corresponding to sustainability on renewable resources, most likely solar photons.

On the other hand, if there is warfare, technology for weapons will be a very highly prized object, and funding will be diverted to accelerate technology development. Of course there will multiple spill-offs from this, not the least of which is the production of trained scientists, engineers, manufacturers and designers. War uses resources and accessibility questions would be part of the researches done for war-fighting. Thus, one of the principal causes of alien civilization collapse too early for star flight, resource exhaustion, would be ameliorated by having a steady diet of warfare, probably one conflict every generation or two, until the limits of weapons of mass destruction is reached and warfare becomes too costly, except on a local scale.

Thus the conclusion is clear, war is likely to exist on most alien exo-planets during their later, but not latest, stages of technology development, and it is possibly a significant contributor to their staving off resource exhaustion, at an early accessibility level, until asymptotic technology is reached and resource exhaustion is put off until much later. If the civilization is fortunate enough to be on a resource-rich planet, this might mean they will have the option of space travel of some sort.

Saturday, June 13, 2020

Geological Separation on Exo-Planets

In order for an alien species to proceed upward through the various stages of technological development, finally arriving at the top level, asymptotic technology, where it might start a starflight project, it has to have access to resources of many types. Energy sources are of course on the list, as without abundant easy-to-obtain sources of energy, the aliens cannot move into the industrial phase of development. Without large areas of fertile soils, they cannot even get far into the agricultural phase, and are forced to languish in the stone age until they become extinct.

There are more. The industrial era needs some mineral resources, such as iron and other metals, and as the age progresses, more and more elements and compounds are needed. The history of technology on Earth might be written as a history of materials and their availability, and it is the same for any alien species on an exo-planet. For example, one cannot have the massive computational capability needed to move into the artificial intelligence phase unless there are the unique materials needed for processors and memories, as well as other electronic components. On Earth, we started with vacuum tubes, which only require some glass, tungsten, copper and maybe a few more. But one cannot get far into heavy duty computation without the invention and deployment of transistors.

Where do all these materials come from? Some are directly obtained from mining, and others are produced from mined ores and their derivates. Hydrocarbons have to be included as a mined material, as many products include hydrocarbon derivates. Would these all be available on every exo-planet?

Not all dust clouds in the galaxy are equal. Before a star condenses and forms a system of exo-planets, it receives the residue from some supernova explosions, which are the accepted generator of higher atomic number elements. A huge tsunami of neutrons comes rushing out of the stellar implosion, and these build up existing elements to ones higher in atomic number. A particular gas cloud, prior to condensing to a star and a planetary disk, might have had a large number of large supernova and therefore be very rich in elements, or it might have not been so fortunate, and the star condenses with a planetary ring having little iron and the whole slew of other useful elements in it. This means the planets cannot have rich resources for any alien species which develops intelligence on one of them. It is not clear why an alien species could not develop on such a planet, so it could be what we call an origin planet, but it is one which will never have an alien civilization that could build a starship to come and visit Earth.

We should do some surveys, if we haven't already, and see if the galaxy around us is filled with very rich-in-resources clouds or if there are some that are and some that are not. That is one piece of astronomy which would help answer the resource availability question, but it is not the only one needed.

The other half of this question involves the accessibility of resources. Suppose we have a planet which condensed from the inner part of the disk where there were lots of resources, and the free hydrogen and helium all escaped, leaving a planet like proto-Earth. Does geological separation into the crust automatically follow? The planet upon condensing would be molten, from the huge release of gravitational energy, and it would be radiating its energy outwards as heat, gradually cooling. The outer surface of the molten droplet would get cooler faster, as the cooling happens faster than the conduction of heat from the interior. So a crust forms, but does it have separated ores? Ores need to be separated to a large degree, or they are inaccessible to the aliens.

If we had, on Earth, exactly the same set of elements in the crust, except they were not separated out but the crust was fairly homogeneous with a little of this and a little of that, in roughly the same proportions, everywhere, there would be no use in mining. There would be no point in searching all over the planet for some concentrated source of some industially important material, as it would be everywhere in tiny concetrations and nowhere in large concentration. Thus geological separation of various ores is a critical and mandatory requirement for the development of an advanced alien civilization.

We have one example to examine: Earth. We need to know if Earth is unique or ordinary, as far as geological separation is concerned. There can certainly be all kinds of degrees of this, so ordinary covers a huge plethora of types. There could be an exo-planet, with an even higher degree of separation, so at different points on the surface of the crust, there would be mountains of cobalt ore, or mountains of germanium ore, and more and more. Or it could be that an exo-planet has the same ores as Earth, but they are just smaller in amount, and harder to obtain. There is a question of the cost of accessing these ores. They produce some benefit to the alien society, at whatever stage in technology development it has reached, and if the benefits are small compared to the cost of mining, processing, refining and transporting them, they would not be mined. The society would not have them around to develop new applications and new technological uses, and therefore new technology. With costs of obtaining resources prohibitive, it is just as bad as if the primordial gas cloud was less rich.

Do we understand the process of geological separation of ores, quantitatively, so that we can compute some estimates of the existence of large, low-cost deposits on other exo-planets? When condensation happens, everything is mixed together, and immiscibility in the molten drop, perhaps mostly of iron and those elements which mix well with it, will lead to a separation. The ores which separate out, condensing somewhere in the molten planet, and which have density lower than that of the drop itself, will rise up to the crust, where cooling is taking place. These bubbles of molten ore might reach the crust anywhere, so the crust could have any type of ore anywhere. How big do the bubbles, which are concentrated in a few elements, specifically metals, with some carbonate or sulfate or other anion attached, get? The ones which are lower in density move upwards faster, but do they have time to grow larger? The slower the rise to the crust, the longer the time for a bubble of ore to grow. Several ores might be tangled together, leading to a mixed ore region, but that might actually help in the cost of accessing them. If the crust cools too fast, they don't rise up to near the surface, but are stuck below where they are too deep to practically dig out. What would keep a proto-planet from cooling to fast? Tidal friction from a large moon, in close.

The Earth, as far as we can tell now, is unique in that its moon is a large mass fraction compare to other satellite-to-planet ratios. Did the tidal heating from the moon, shortly after it was formed in a planetesimal impact on the proto-Earth, keep the crust hotter and thinner so that ores could form in large volumes more easily? If this is so, there might not be only one reason why a large moon is necessary for an advanced alien civilization but two: life originates with the moon's influence and ores form in larger quantities with the moon's influence. What an astronomical coincidence...

Sunday, May 3, 2020

Can Bioterrorism End Alien Civilizations?

'Terrorism' is used here to refer to small-scale groups attempting to achieve some political ends through the use of terror attacks, which are attacks designed not necessarily to cause great destruction, but to induce terror in a significant part of the population of a target region, which will then bow to the political demands of the terrorist group. Technological determinism says that technology dominates social change, and it may also dominate terrorism, one facet of a civilization.

In the early eras of technology, where knives and poisons were the only available weapons, assassination was the only type of terrorism that could occur. Directed against leading members of the alien civilization's government or economic structure, a terrorist group could hope that concessions might be made to their cause if the leadership felt unable to protect themselves. Infiltration of the ranks of those with guardian capability might be one of the social tools such a group might use, and suicide attacks might inspire the terror they needed to accomplish their ends. 

The invention of controlled combustion might lead to projectile weapons, but these simply make assassination easier. Bombs, however, open up a new avenue for terrorism, and that is attacks on infrastructure or on the public themselves. These weapons have the most effect in crowded places, and the obvious countermeasure is control of those entering these places, with some sort of measures designed to detect such explosive packages, along with the ability to carefully search the areas, arenas or whatever places a particular alien civilization likes to attend in large numbers, to eliminate such weapons from being installed and hidden prior to the crowd's arrival, for places with sporadic use. Continuously used places would have continuous checking in place or lockdowns during non-used times of the day. 

The advent to nuclear technology, in the middle of the industrial era, does not change much for terrorism. Nuclear weapons are very difficult to design and assemble, requiring specialists of many varieties, and terrorist groups are unlikely to be able to obtain such a quorum. They also require multiple unique materials, some very difficult to make from other, more easily available ones. Since nuclear weapons contaminate great areas of any planet where they are used, all regions on any exo-planet with an advanced alien civilization would be motivated to cooperate in restricting access to these end-materials. The costs of a nuclear weapon program are great, and if terrorism is something small groups would use, they would neither have such resources nor be able to deploy them, if they found a donor. The weapons are also large and hard to move and hide, and they give off telltale radiation, which can serve as another means of detection. Thus, the advent of nuclear technology into the collection of useful technology does not make terrorism any more powerful or easy to apply, just the opposite.

The beginnings of biology, specifically the biology of infectious organisms, may be a different story. The ability to capture an existing infectious organism, and mutate it, requires little money or expertise. Even a single talented individual alien might do this as the technology is not complicated to understand or utilize, once society gets some basic knowledge into its storehouse of scientific understandings. Recall that psychology and neurology come later on, so that the ability of the society to detect some mentally disturbed alien, having such a capability, is limited. This means that an alien society in this particular phase of its industrial era can be victimized by individuals or small groups who concentrate on contagious organisms. 

This capability exists even below the level of a terrorist group. Curiosity or some sociopathic desires could motive individual aliens to explore what they could do in this area, as there may not be any knowledge yet about how to train young aliens to prevent their involving themselves and others in dangerous activities when they grow older and more informed and educated. Neither would politics be a solved science by this time, so there may be personal or political disputes that could motivate such talented individuals.  They might develop some organism, protect themselves and those they care about, and release it to see what happens. If it was based on an infectious organisms, the mutated version might be contagious as well. 

If amateur biologists can create mutated viruses, what could a terrorist group do? They might be able to operate in two stages, one: where they try all types of viruses in different locations to see which ones might serve as a terror weapon, and two:, bioweapon where they induce some cases of their chosen infectious organism into some locale that they have access to. 

A bioweapon attack, even on a small scale such as a terrorist group could manage, requires social controls to be put in place, rapidly and severely, if the contagion is to be controlled at a very low level. Those regions which can do this might be relatively immune to bioterrorism, but those which are not, for any of several reasons, could be held at risk by a bioterrorist group. After one or several bioterrorism attacks, it might be clear to all regions that they need to prepare themselves against such attacks. One way might be to scour the whole exo-planet for biology laboratories that bioterrorists might exploit, but since they can be quite small and do not need exotic unique materials, finding them all might be difficult. The other way, if the region has the resources and the governmental excellence to do this, is to organize a reaction to any attempts at bioterrorism, all the while reducing the locales at which it could be done. 

If these countermeasures against bioterrorism, in attacks or in threats of attacks, are quite expensive to a region, it might try to negotiate its way out of them with one or more bioterrorist groups, but since they can form easily, this might not be a long-term solution, and the expensive countermeasures are the only solution. If the costs are so large that the alien civilization suffers a reduction in affluence, in living standards, and in the means of survival, then perhaps the civilization will begin a slow collapse. 

The other solution that might be taken is technological suicide, where the alien civilization as a whole seeks to ban biological knowledge from being gathered, collected, or disseminated. This means that asymptotic technology will never be reached, the ability to diffuse bioterrorism will never be accomplished, and the civilization will go into stasis and collapse. A solution near to that is to strongly limit the knowledge of biology to tiny numbers of aliens, in the hope that this knowledge will not diffuse out to potential bioterrorist groups. This would seem to be a more rational solution, as it allows work on automatic generation of antidotes and antigens to continue. Thus, bioterrorism might certainly slow down the progress of an alien civilization, but it is unlikely to destroy it, and would therefore not be the method by which aliens are prevented from reaching Earth.

Biowarfare and Alien Civilizations

Warfare has been so common through the last several millenia on Earth that it might be thought to be inevitable that it would occur on all exo-planets with thriving alien civilizations. The killing of other individual aliens and the destruction of their property, on a large scale, can be motivated in many ways. It might be the equivalent of envy, hatred, greed, love of destruction, desire for power, wishing to spread one's world-view or religion, fear, and likely others. Since there are so many reasons for having a war, wouldn't there necessarily be some?

The antecedents of mankind's love for war might be their evolution as hunters. Killing large game and killing other aliens is not so much of a jump in direction as eating only fruits and vegetables and then starting to kill other aliens. Can only omnivores evolve intelligence and eventually a civilization, or could herbivorous creatures do so as well? 

Perhaps this question should be asked in a reverse manner. Can herbivores who develop tree-climbing ability and then grasping appendages stay herbivores, or would the ability to reach nests start them on the path to eating eggs, newborn animals, young animals, and lastly full-grown animals? Raiding nests on the ground might start them off on the same evolutionary track. Given the nutrient value of eggs and young animals, this track provides significant advantages, and therefore it is likely that such creatures would not stay herbivores, but would evolve, step-by-step, into hunting animals, and then into tool-using hunters. This is the likely step before killing one another, and then as groups form, so does the concept of warfare. Warfare is therefore likely in the history of most alien civilizations in the galaxy.

Technological determinism says that society is shaped by the level of technology it has achieved. Warfare, as one feature of society, is also determined by technology, and as technology travels from stone and wood tools, to metals of ever increasing strength-to-weight ratio, to combustion in various forms, and onward to machinery, so do the tools of war. In the later stage of the industrial era, on planets with uranium in the ground not already decayed into too much U-238, nuclear weapons should be invented, and then the society would quickly realize the disutility of weapons of so much destructive power and requiring so much expertise to use. 

There is likely an overlap between the genetic era, when biology is being understood in many of its details, a precursor to genetic technology, and the last stages of the industrial era, that of electronics, automation and robotics. Breeding of plants and animals would have been proceeding for the whole age of the society, using trial-and-error techniques, and as the understanding of disease becomes widespread, the concept of bioweapons does also. One can use trial-and-error methods to breed disease organisms as well as socially useful organisms. Initially, the analogous use of bioweapons would be tried, similar to chemical weapons, such as by explosive canisters or sprays, applied on the front lines of armies, but these methods have quickly-discovered drawbacks of self-contamination and countermeasues, such as personal protective equipment.

Contagion is a more appropriate use of spreading a bioweaponized virulent organism. If one region has a particular and unique type of crop, which provides a substantial fraction of the nutrition for this region, then an enemy region could attempt to devise infectious organisms which would spread widely through the crop, eliminating its value. If the crop was annual, the yield would plummet. If it was a perennial, the productive plants would fail to grow the product, or even die. No such type of attack would work if all regions grew the same range of crops, however. Analogous arguments would work for animal husbandry as well.

If there was some unique genetic characteristic that most of the inhabitants of one region possessed, and it were possible to breed an infectious organism that would only attack those inhabitants with the particular feature in their genes, an analogous attack could be made. However, if this genetic dissimilarity is not wide-spread, or no organisms can be made to focus on one that exists, biowarfare can only be accomplished through a more organized and insidious means. If contagion is the means by which the infectious organism spreads, then the attacking society must somehow have some characteristics that allow it to be only slightly affected, which the opponent must have the opposite characteristics. If the disease is mediated by insects which live in unhygienic environments, a hygienic region could attack a unhygienic one. The reverse is obviously not true, but if there is any infection-carrying options, such as pets of some particular type, these might serve as the vectors for the disease contagion. 

If the disease spreads only from dead bodies of victims, then burial details might make one region more susceptible to being the target of a biowarfare attack. However, this is something that could quickly be recognized and altered, so such an attack is problematic at best.

If the disease spreads only through direct sharing of bodily fluids, such as blood to blood, it is not likely that it could be transformed into a bioweapon. There might be the equivalent of Earth's mosquitos on some particular exoplanet, but insect control is not difficult in an industrial civilization. Thus these diseases also would not serve well as bioweapon candiates. But if the disease could spread through indirect sharing of bodily fluids, or even without bodily fluids being used on the whole transmission path, then there might be a possibility of a bioweapon. If the infectious organism can spread through touch, or live on any kind of common surface for a period of time long enough for mutiple aliens to touch it, or travel on dust particles or water micro-bubbles, then the disease could act to have a large degree of contagion. 

If the attacking region has a way to prevent such sharing because of social customs or other social controls, and the target region has different customs or no ability to install social controls, then the opportunity for a bioweapon war might be possible. It would not look like any other type of war, as there would be no battleground or front lines, no armies involved in mass attacks, no industrial war machines being used, and perhaps even no declaration of war. The only thing that would happen would be one region would succumb to a high level of fatality, while another would not. Then economics would finish off the struggle between these two regions.

Could one or more biowarfare wars doom an alien civilization to collapse and never reaching star travel? This is not likely to happen, as social controls can defeat a bioweapon attack or serve as a protection of an attacker, so society might have some economic disruption during the period of the attack, but the attacker would not lose their grip on technology, nor suffer a great deal of economic disruption, and would be able to control the other region or regions and continue to pursue technology and eventually get to asymptotic technology. After this point, infectious organisms are easily controlled and no biowarfare would make sense, as antidotes and antigens could easily be generated as soon as the infection was noticed.

Recovery from Epidemics in Alien Civilizations

If an epidemic sweeps through an alien civilization, reaching all corners of the planet, and is lethal to some percentage of the population, the main drivers of the civilization's progress are not affected. Population count is not a direct cause of technology progress, and it will continue after some delay caused by the epidemic. What is important to maintaining the progress is having a quorum of intelligent, problem-solving individuals who can organize their work to push the envelope of science forward, and then to apply it to the productive activities of the population. If there is some fraction of deaths, maybe even as high as 90%, this does not mean that the genetic resources that are needed to produce the future generations of scientists and engineers are lost, it means the numbers are reduced and progress will be slowed down, or even degraded for a period of time. But it does not mean a permanent halt, and the timeline for this society to be able to make star travel work might be delayed for a few generations. 

To kill off the civilization as far as permanently eliminating their future progress, there would have to be a lethality level near to 100%, enough to eliminate so many of the population that there was a genetic reduction in intelligence. Is such a lethality level possible? Something lower than that might render the civilization incapable of maintaining its living standards, or even to preserve the existing level of technological know-how, but physical records and memories passed on to young aliens would lead them back to the standards they once had, and allow a resumption of the progress toward star travel.

Can an epidemic kill 100% of a population? This means that the contagion spreads world-wide, and that takes time, during which awareness of what is happening would travel all over the planet. Some response would be made, and the figure would drop below 100%. In the industrial era, when epidemics are possible because there is world-wide transportation and not yet rapid genetic developments of antidotes and antigens, there are still recourses to reduce the impact of the epidemic. Furthermore, with a wide mix of genetics for the immune systems, optimality having not yet been accomplished or even understood, there might be some aliens who are naturally immune, constituting some fraction of the population. And there might also be some individuals who are mostly resistant to the infectious organism's effects, recoving from it in more or less unimpaired condition. So, the achievement of 100% or very close to it lethality is unreasonable to suppose.

Before assuring ourselves of the recovery capability of a generic alien civilization, we might ask if there are any circumstances in which such a recovery might not happen. Regrowth needs resources, and if the civilization has already harvested the easy to gather ones, the minerals near the surface for example, could there be a barrier set up so that the civilization is bound down to a lower level of technology, one not capable of difficult extraction situations for critical items? Technological progess and resource development go hand in hand, and if the latter is impaired by what happened before the epidemic, could there be a strong barrier, sufficient so that the civilization would remain at some level, industrial or agricultural, forever? 

This is a question related to the particular planet upon which the civilization resides. Does the planet have large, relative to the usage rate of the population, amounts of most necessary minerals and energy resources? Or is the planet, owing to where it developed and the history of supernova generation of heavier elements in the clouds nearby, rather short of resources? If the latter instance, could the near exhaustion of resources in the industrial era could leave the surviving civilization with only too-hard-to-obtain resources remaining? This means that, during this alien civilization's industrial era, no one noticed, or if it was noticed, no one responded to the problem, and the resources available to the civilization were rapidly diminishing and growing harder to locate and recover, and instead of the obvious solution toward reducing usage with a world-wide reuse plan, they simply continued to work toward an early resource exhaustion. 

This does not make sense to rational people, but could there be some economic system which drove resource exhaustion heedlessly and recklessly. Could such an economic system stay in place when the costs of resources mounted steadily and significantly? This is an excellent question about the unbreakability of some economic systems. Can they be so firmly embedded in the culture that they would be blindly followed to near-term self-destruction of the civilization? Economic systems are in place because those who have the power to determine the ones to be used benefit from them, and so this question is, could these leaders of an alien civilization be only concerned with their own short-term benefits, and dismissive of what will happen to the civilization as a whole in only a few generations? 

This question takes us further afield. Recall that the science of training children, which involves setting goals for them in the deep subconscious, may be completely unknown to the civilization, and child-training and goal-setting left to random choices by those responsible for that training. Thus, short-sighted goals might be preserved, generation to generation, including the goals that those who become leaders have. This particular realm of science is likely only able to arise in the later part of the industrial era, that of electonics and automation, or even in the early part of the genetics era. 

There may be other mechanisms by which an epidemic could put an end to the future of an alien civilization, barring them from space travel, but this is one. It would only occur on a planet with less abundant resources, measured by how long they last during the industrial era, and only in situations where the neurology and training area of science happens to blossom late in this era. In this particular and possibly rare situation, a world-wide epidemic could have indirect effects that could collapse the civilization unrecoverably. But not only would these two requirements have to be in place, the epidemic itself would have to be at the limits of lethality, via both the disease effects and contagion. It might be that the evolution of such an infectious organism is extremely unlikely, and only by some early efforts at genetic engineering, at the level that would be possible in the later industrial era, could it arise and be, possibly accidentally, released.

Disease and Contagion in Alien Civilizations

The two aspects of epidemics are disease, what the effects of the infectious organism are within an alien's body, and contagion, which is how the infectious organism migrates from one alien to another. There are relationships between the two, but it is convenient to think of them separately at first.

When the infectious organism is inside an alien's body, that body serves as the source of sustenance for the organism. Somehow the infectious organism needs to get access to those substances that will allow it to survive and multiply. Cellular walls surround useful substances everywhere but in a few locations, such as the digestive tract and the equivalent of the blood system, meaning whatever in an alien's body transports nutrients, including oxygen, from the source locations within the body which access them from the outside. In Earth land creatures, those source locations are the lungs for oxygen and the digestive tract for everything else. So, an infectious organism that does not need oxygen directly can live in the digestive tract; otherwise it must somehow obtain its own nutrients from the body of the alien. There are nutrients in the blood system equivalent, and if the organism can somehow penetrate the walls of that system, it might find a place to survive and multiply. Thus, moving from the entry point on the alien's body to the blood stream has to be done in one way or another, and through a wound is one. Wounds should be uncommon, however, and so they would only play a part in diseases which cannot become epidemics. 

This means that the infectious organism has to have one unique capability: penetration of cell walls, either directly into cells themselves or between them into organs which have fluids, such as the equivalent of blood vessels. This can be done by toxins, which cause cells to die, or direct microchemical attack on the cell walls or their adhesion system, which binds one to another. This elementary categorization simply serves to show that the functionality of infectious organisms is not very diverse nor very complicated, and that there is no obvious reason they could not evolve on any exo-planet with animal life. It also means that there might be a multitude of types of disease-causing organisms on any exo-planet of this kind, where the next level of specification is by the type of cell in the alien's body which is attacked by the organism. 

There would be cellular defenses against infection, and also body-wide defenses, which are the equivalent of our immune system. Cellular defenses involve resistance to toxins which kill cells and resistance to penetration attacks on the cell walls and on the connections between cells. Body-side defenses involve organs within the body which produce cells specifically designed to attack and destroy infectious micro-organisms. Evolution continues to improve and adapt both sides of this battle, and while there is a degree of randomness in what evolution has produced at any given instant in time, over long ages everything gets tried that can be tried.

Every disease-causing organism would like to graduate to being an epidemic, as the numbers of the organisms would be multiplied by something quite large. Thus, evolution would also work on micro-organisms to enable their transfer from one host to another. However, there is no biological equivalent to inter-host transfer, so evolution has no way to arm the larger organisms against this in any direct way; instead defense has to be left to each large organism to defend itself against the infection. 

One piece of knowledge that is widely understood is that highly and quickly lethal organisms have a hard time spreading from host to host. There is no evolutionary advantage for a micro-organism to kill its host quickly if it can live within the host for a long time, while propagating to other hosts. If the micro-organism has evolved to overcome the first line of defense of the host, the cell walls, it can live until the immune system rises up to eliminate it. Since this takes time, measured in the rate of transfer of cells around the body of the host and the growth rate of the different types of cells that make up the immune system, there is a duration of infection that should not be shortened by evolutionary mutations within the infectious organisms; otherwise the micro-organism works to its own disadvantage. The longer the duration, the more multiplication of micro-organisms that can take place, before the immune system eventually reduces them again. 

The method of contagion plays a role here. One route for the micro-organism to spread between hosts is via death of the host and spread of the organism from the dead body of the host. If the micro-organism can live for a long time in water, any host which dies in water can spread it. If the micro-organism dehydrates the host, the host would seek water and perhaps die in contact with it. If the micro-organism infects hosts which are carrion-feeders, and cannibals to boot, this would provide another route for re-infection. This, of course, is only for wild creatures living in natural surroundings. For intelligent aliens, burial customs can influence contagion in a somewhat advanced alien civilization. Using dead animals as feed for live animals of the same species can also be involved. In such instances, lethality of the micro-organism might be higher than otherwise optimal for its propagation. 

Otherwise, the game is played by set rules, the host should live until the immune system kicks in, or would have, had the host not died from the infection. The infectious organism has to have ways to propagate, either while the host is alive and infected, or while dead and not buried, or both. These are categorized into respiration-related, touch-related including sexually transmitted, and surface-transmitted. Third parties, such as insects, can also serve as the route for contagion. For primitive alien civilizations, all of these would be in play until enough technology is gained to block them. After that, one by one they are shut down, by eliminating the insect hosts, by disinfection methods, by identification of carriers and their isolation and possibly others in special cases. So, epidemics can strike an alien civilization in analogous ways to ours, and the question about whether epidemics could be the reason alien civilizations are not visiting us depends on whether or not, at any era within the development of the alien civilization and its technology, there would be enough planet-wide transportation before anti-epidemic technology was developed. In other words, which technology stream comes first. 

Lastly, there is the question of the finality of an epidemic. Given that one happens in an alien civilization, can it recover and get back on the road to star travel, with only a delay of a generation or two or three? This might be a much more important question that the possibility of a single monstrously severe epidemic at just the right time in the technology development cycle.

Can Epidemics End an Alien Civilization?

Recently, a well-known blogger facetiously proposed a possible solution to the question of missing aliens: could epidemics have killed them off? This deserves some detailed examination.  This post and the next four all attempt to dig deeper and to provide some overview of the possibility.

Would there be infectious organisms on exo-planets harboring advanced alien civilizations? What helps us answer this is one of the main principles of alienology: convergent evolution. This principle says that the number of mutations that happens on a planet is much, much larger than the number of possible mutations; in other words, every mutation is tried out many times. Since evolution favors the more efficient at survival and reprodution, we would see on each exo-planet that has originated life and undergone billions of years of evolution, all the same niches of life filled. There might not be, at any instant in time, rose bushes on Planet X, but there would be flowers, thorns, pollination in different ways, fragrances emitted, and so on. Everything that works here would have been found and worked there, subject to lots of randomization. The principle works the other way as well, as anything that evolution could have come up with on Planet X, it could have come up with on Earth. The details are all scrambled, but the niches are occupied, the various functions are all there, and so on. 

That means that multi-cellular organisms on Planet X, where “multi” means billions, would be good homes for both infectious single-celled organisms and semi-alive RNA/DNA/protein globs which we call viruses. This has to be tempered with the realization that immune systems would have evolved in the organisms on Planet X as well, and that means that each organism there is actually a battleground between cells and viruses that would like to colonize it, and the organism's immune system cells, which are bent on getting rid of these things. The immune cells have to be able to communicate with whatever organ makes them, so they can call up large numbers when a virulent invasion hits, and so they are unable to go everywhere in the body of the organism, particularly not in the digestive system and the outside of the envelope or “skin” of the organism, plus a few other places. So infections would hit the organism in the digestive tract or on the skin of the organism. The oxygen supply system would also be an area where the immune system cannot easily patrol in large enough numbers to repel a large invasion. 

Another principle of alienology is asymptotic technology, which says that technology is an accumulation of scientific knowledge and engineering principles which builds on itself over time in a society of intelligent organisms, and has to follow some fairly well-developed paths based on how knowledge fits together and how engineering of various tools allows the next stage of technology to be developed. Iron tools allow deep mining to be accomplished; computers allow DNA to be investigated; and on it goes in a reasonably coordinated way. This way comes to an end when all technology is understood, and that does not take very many generations of aliens, perhaps something of the order of a hundred. The final stage is called asymptotic technology, meaning it is the final end or asymptote of technological progress. 

Genetics is one of the last pieces of technology to be brought under complete control of an alien civilization, as it depends on the pre-existence of much other technology to enable all the experiments that have to be done. An alien civilization which has reached asymptotic technology does not have any worries about epidemics of single-celled organisms or viruses. Any individual who become infected can be examined and equipment used to determine exactly what is the infectious agent and what does the technology library say about how to get rid of it quickly. We are not at the stage yet of knowing how to do this, but we can imagine some possibilities, none of which have to be discussed here. What is important, is that there is no mysterious illnesses possible with a sufficiently advanced alien civilization, meaning no epidemics, even locally. All bets are off on an exo-planet which has had its civilization collapse for other reasons, but one which is in the golden age of its existence will have no problems.

This means that epidemics occur only with younger alien civilizations, ones which have not yet passed the genetic grand transformation, after which genetics is wholly understood, and the technology for dealing with it developed and deployed. An alien civilization in the electronics era, the one prior to the genetics revolution, does not have the ability to analyze almost instantaneously genetic blueprints and fabricate antidotes. Instead, such a more primitive alien society must grope around, using trial and error, in the hope of finding a cure for any widespread infection or a vaccine to prevent it by giving the immune system a head start. However, if infections can produce a sufficiently widespread and catastrophic effect on such a early civilization, it would not have a chance to reach the genetic grand transformation, and would relapse into some earlier stage. 

Could an epidemic occur in an alien civilization which has not even reached the electronics or industrial age? This would be a civilization in the agricultural era, where there are few small cities, and the population is spread out over the planet in regions where agriculture is efficient and seasonality not too severe. There might be a slowly moving infection, but with very limited numbers of individuals moving from one area to another, there would not be anything to produce a catastrophe. If the infection was highly lethal, news of it would spread faster than the infection itself. If it were rarely lethal, it would simply become part of the arsenal of the resident aliens' immune system. Thus, epidemics occur in industrial civilizations that have mastered transportation to some degree, not in earlier or later ones.

So the question resolves to: can an alien civilization which falls victim, over the whole planet, to a single type of novel infection, recover from it and with some delay, return to its progress toward the further stages of technology? If the infection is sufficiently lethal, its spread is inhibited. If the infection is not very lethal, it becomes part of the immune system's library of known invasive organisms. Exactly what lethality is needed for a collapse after which there is no recovery, even after a century? If it is too high when it arrives, carriers do not carry it far before expiring. However, if there is no immune system response possible, in other words, if the attacking organism can defeat the immune system of the individual aliens so they do not develop immunity to it, and can then invade and re-invade and re-invade until lethality results, but with plenty of transmission between individuals during the intermission between successive invasions, this might do it. So, an epidemic which attacks the immune system or which is 'immune' to the immune system, which damages individuals on the first attack instead of killing them leaving them more vulnerable to future infections, and which is easily contagious, might eliminate the alien civilization, and prevent it from ever building starships and coming to Earth. Such an infective organisms, a triple-headed threat, might be stopped with social measures in an alien civilization in the industrial era, but that is another question to be answered later.