Stan Erickson's Alien Civilization Blog

Mankind Rescues the Earth!

noreply@blogger.com (Stan Erickson) — Sun, 28 Jul 2024 18:09:00 +0000

One of the biggest events in Earth's four billion year history is the oxygenation of its atmosphere. Around two and a half billion years ago, it is believed that some newly evolved organisms, cyanobacteria, developed a kind of photosynthesis, which produced free oxygen and used up carbon dioxide. At the beginning of this process, the atmosphere was mostly nitrogen with the rest largely carbon dioxide. At the end of the process, lasting perhaps hundreds of millions of years, the atmosphere was still mostly nitrogen, but oxygen had replaced almost all the carbon dioxide.

This process involved a huge number of geochemical and biological changes, but the bottom line is that Earth developed a very unusual atmophere, with free oxygen. The oxygen provided much more energy for organisms to use, expecially on land, and this led to the evolution of man. Hurrah!

Once there were large organisms on the surface of Earth, they went through their life processes, and in a few places, were buried along with the carbon they were composed of. One of these processes involved the burial, maybe under blown dust or dirt, in large number of layers, of carbon residues, which were carried by tectonic processes deeper underground, where the pressure would transform them into coal, oil and natural gas. Another of these processes happened in the frozen taiga, where the surface melts in the summer and plants form, only to die in the winter except for their seeds. All the rest were buried under layers and more layers of frozen ground and ice. There may have also been underwater processes, resulting in buried carbon compounds in the sea floor. There may be even more processes which extract carbon from organisms. All the buried carbon comes from organisms which extracted it from the residual carbon dioxide in the atmosphere, leading to a continued dropping of the concentration of this molecule. Since carbon dioxide is the most essential foodstuff for organisms, this extraction means that it is growing harder and harder for life to exist on Earth.

Those organisms which required more carbon dioxide in the atmosphere than we have now have already become extinct. Over periods measuring in millions of years, the lowering of carbon dioxide concentrations in the atmosphere would result in more and more extinctions, until Earth would be left with only the best carbon dioxide scavengers, living on a planet with little atmospheric carbon dioxide. Someday, if this plan were to continue, they would, one by one, die out as well. Thus the Earth may have been on its way to becoming a bare, lifeless planet.

Enter man. For most of its existence, man had no effect on this process, and indeed no knowledge of it. Fortunately for the rest of life on Earth, a couple of hundred years ago, mankind discovered the bountiful energy that was buried in what we usually call fossil fuels, coal, oil and natural gas, and began burning it. A large amount has been found and burned, and the Earth's horrendous shortage of carbon dioxide in its atmosphere is being reversed. It looks like this will continue, and the change in temperature caused by this, utilizing the greenhouse effect, may melt some of the frozen carbon storage in the northern part of the globe, leading to an even greater rescue of Earth's life. It is not beyond imagination that mankind will someday release some of the carbon buried in the sea floor.

We should not take credit for too much. There are other places the carbon can be hidden on the Earth, and eventually, these will take over and get rid of whatever is left over from the oxidation of the atmosphere plus whatever mankind has found and brought back for life to use. Hopefully, that will be long from now, when the sun is heating up and the Earth is becoming uninhabitable because of its solar-generated temperature. If mankind is successful in the short term in raising the average temperature of the planet a few degrees, life may evolve to endure higher temperatures, but this will only extend the span of life's duration on Earth by some millions of years. It is inevitable that Earth will become lifeless one day, but thanks to mankind and fossil fuels, that day may be in the far, far future, rather than at some sooner time.

Please excuse this tangential note. If you would like to read what I am projecting for the next seven hundred and fifty years of human life, the period of the most exciting changes in all of mankind's history, you can read my book, Looking Back From Luna.

How Long Will Humanity Last?

noreply@blogger.com (Stan Erickson) — Tue, 28 May 2024 02:40:00 +0000

An upper bound can be generated somewhat easily. The sun continues to grow larger and larger, and one day it will become so large, in what is called the red giant stage, that it will consume the Earth. The Earth will have become thermally uninhabitable long before then. This means that humanity, if it wishes to continue to survive, must move somewhere away from Earth before Earth's thermal death. This event is billions of years in the future, and it is much more likely that some event will happen before then to threaten the existence of humanity.

The title question might have several answers, depending on the lifestyle situation of the people. Since it began, human society has been progressing through different forms, which were controlled by the development of technology. The earliest days of human society were back in the Stone Age, many millennia ago. Then someone invented a process for producing copper and then bronze, which allowed some changes to society. Following these developments, iron was discovered, probably simultaneously with charcoal, which permits smelting at a higher temperature. Agriculture was started somewhere in these early ages, and animals became domesticated, both as food sources and as work animals. Wind began to be used, with sails for water transportation and mills for grinding grain. Flowing water was also harnessed for mills.

All this set the stage for the discovery and utilization of fossil fuel energy, first coal, then oil and finally natural gas. These fuels led to a large increase in excess energy, and science and technology began a very serious period of development. Technology led to the utilization of steam power, and later electricity was invented. This led to a plethora of inventions, including electronics and microelectronics, which led to computers. The stream of inventions continues to flow strongly and constantly. This involves the mining of a great many different ores around the world and their transportation.

We might ask: How long can humanity survive at the agricultural level, where more concentrated forms of energy have disappeared? We might also ask: How long can humanity continue to exist at the high standard of living we now possess? But this ignores the obvious fact that society will continue to develop new scientific breakthroughs and technological discoveries. The rate of change is astounding, compared to earlier eras; it is unlikely that society only one century from now will be very similar to what it is now. This problem may seem unsolvable, but it is not. It is fortunate for our discussion that science is not infinite, but instead there are only a finite amount of discoveries that can be made. As more are completed, diminishing returns sets in, until some asymptotic value is reached. Science doesn't stop entirely, but since almost everything will have already become known, there are only some smaller details that need to be figured out. Thus, we can also ask, how long can humanity survive at the era of asymptotic technology?

Society might be capable of destroying itself, so we need to ask these three questions under the presumption that humanity has started thinking about its long term future and can make the choices necessary to avoid damaging its future prospects or even committing social suicide, as with a nuclear war or horribly malevolent virus. Now the questions appear to be more nicely framed: given that humanity adopts the goal of lasting as long as possible, how long would this be for us, at an agricultural level, at the current industrial and electronic level, and at the asymptotic level?

What exactly does it mean to make choices to promote the long-term survival of humanity? It is necessary to come up with a list of events that might put an end to us and then see what mankind might do to avoid them. At the agricultural level, having the soil become depleted and gradually produce less and less food every year is one possible problem. This problem is quite noticeable and could be coped with, over the course of many decades, by the means already devised for preventing soil death. Growing fewer crops is the simplest solution, and growing non-edible restorative crops certain years is another. But there must be enough food to feed the whole population, so the essential answer is not to allow the population to exceed the number that can be fed using sustainable practices, in the worst years of agricutural productivity. It would also be worthwhile to develop storage for a few years of food to allow humanity to get through the very worst years, which might be years in which volcanic dust so fills the upper atmosphere that sunlight is blocked and crops fail all over.

It would be most interesting if a few groups of people who like accounting and agriculture would make the calculations necessary to give us an indication of what the population and storage numbers might be. Their results would depend on some assumptions about transportation. If one region of Earth suffered from, say, serious floods, could other regions supply them for a few years by sailboat shipment of food and other recovery supplies? This might affect the calculations. As a wild guess, based on historical numbers, a half billion might be the maximum headcount for our planet in these restricted circumstances. There would also be a minimum number of people necessary to maintain all the operations of this future agricultural society.

This level 1 future society would be vulnerable to catastrophes. There are many, both geological and astronomical. The one most familiar is that of a large asteroid that somehow manages to score a direct hit on Earth. If it were large enough, all large lifeforms would die out. The asteroid might rupture the crust, leading to what is called a basalt flood, where lava from the mantle flows to the surface for thousands of years, polluting the atmosphere and killing off much plant life. Basalt floods can also occur without the intrusion of any asteroids, and there is evidence of them in many parts of the world. Another possible catastrophe is a nearby supernova, sending enough gamma rays to the surface of the Earth to sterilize everything. Less well known would be the passage near our solar system of a black hole or star, which might disrupt the stable orbit of Earth, causing it to move to a different radius or change its eccentricity, rendering it uninhabitable. A massive ice age could also lead to an end to human society.

A level 2 society depends on having sufficient energy to run much machinery and computation, enabling a higher standard of living than can be accomplished with an agricultural-only society that lives on sunlight alone. Fossil fuels are what have brought us to this standard of living today, but they will be depleted soon enough, probably a few centuries more at the most. Nuclear power does seem sufficient to replace fossil fuels, perhaps with some optional additional contribution from what is called renewable power. This includes hydropower, wind farms and solar panel acres. It is not clear what will be the constraining resource in such a society. Perhaps it will be thorium, perhaps lithium, perhaps rare earths, perhaps something entirely different. These calculations cannot be made at the present, as we do not know exactly how such a society would be organized. The profligate use of resources would certainly have come to a halt, but there would necessarily be some resources used every year, and some one of them would run out sooner or later.

Such a level 2 society would also be subject to extermination by the same list of catastrophes that the level 1 society would, but there is a saving grace. It may be possible to establish self-sustaining colonies on other planets or satellites, either within or outside of our solar system. This project is even more hazy than the project of revising society to conserve resources and be efficient at energy use. It might be possible, but there could also be some unforeseen barrier to such colonization. We are too immature scientifically to make a good call on this question. However, the length of time that humanity can survive is very dependent on the sustainability of such an insurance colony. If the mean time between life-destroying catastrophes is a few million years, having a colony somewhere would multiply that many times over. It is not even necessary that the colony prepare to reconstitute life on Earth after the catastrophe, as long as it can continue to survive and someday establish an insurance colony of its own. A recent book, “Looking Back from Luna”, is built on the hypothetical possibility that a sustainable colony can be established on the moon, and one theme of the book is the discussion of these colonists about what they might be able to do were a catastrophe to strike Earth, but not them.

The level 3 society takes some real imagination to contemplate. This society would have gone through several future technological revolutions. These would likely include a genetics revolution, after which genetics would be as controllable as software and would become industrialized like software. It would also likely include a neurological revolution, where we learn how to maximize both the non-verbal and verbal learning of humans, and thereby increase their resulting intellectual capability. This would have education and psychological developments as fundamental components. There would also likely be an organizational revolution, where politics is replaced by some form of governance that looks forward to the long-term prospects of human society.

Even though there are many, many options for organizing such a society, and few of them could be determined by us now, they would all still be subject to the similar limitations on energy and mineral resource use, just as a level 2 society would be. This means they would have similar expected endurance as a very-high-tech society as level 2 would have, within a factor of ten most probably, and would require the same option of a self-sustaining colony as insurance against catastrophes.

So the answer to the title question is much the same for all levels of society, and it is the mean time before a catastrophe hits. Is this a million years? Can Earth's resources be stretched to last this long? We are not even capable of making this estimate except as a simple guess. It is clear, however, that for levels 2 and 3, if the population becomes serious about having humanity last for a tremendously long time, measured in millions of years, figuring out how to establish colonies on other planets, which would be self-sustaining for long periods, is perhaps the most important project we can undertake.

Small, Old Civilizations

noreply@blogger.com (Stan Erickson) — Thu, 09 Sep 2021 20:26:00 +0000

Since there are no signatures, at least bold, obvious ones, that there was a large, ancient civilization before our era, the possibility of a small, ancient civilization needs to be examined. When we say small, we mean one which stays below some fixed population count. The population limit is small compared to modern populations, or even ones of a century or two ago. The number might be tens of thousands or hundreds of thousands of people.

Why would a civilization keep its numbers down, especially in early eras when the concept of resource exhaustion would not have been known? What motivations could there be for limiting a population? Civilizations, especially early ones, are led by some individual, or in rare cases a small group. So the question really is, why would a leader take actions to limit the population of the people he governed? The usual case, in our history, is that leaders never do such things. Perhaps they might be forced to.

Suppose a tribe lived in a river valley, and a chieftain long before had established a belief system which included the rule that anyone emigrating from the river valley was insulting the chief and betraying his tribe. It would be easy to have this incorporated into the theology that was around at the time, as theology has the knack of adapting to rulers' desires, although not in an obvious manner. So, if this one chieftain had felt insulted and started this tradition, the population outside of the river valley would stay at zero. Perhaps the tradition includes any secretive emigrants being hunted down. With this rule in place, there is no possibility other than a limit to total population.

A river valley such as the one in this example would have a certain amount of water flow, from the river and from rain, and that might be the limiting factor in how much food could be grown. Some years might be better than others, but when a bad year came, or a stretch of drought years, the limit would be unstretchable. After some decades or even centuries, it would be known just how many people could live without threat of starvation during the bad periods, and some sort of reproductive control might be needed to accomplish this. Shaman medicine might come into play here, if an herb was found which caused temporary infertility, without much else in side effects. The civilization would have to have some rules for who is allowed to have how many children, but they could be any type of rules at all, as long as the maximum was not exceeded.

Thus, it is not difficult at all to envision a civilization which had a limited population over a long period. It just needs a geographic limitation enshrined in the tradition and the religion, and a means of controlling reproduction, such as a herb or other plant product. There might be other means as well.

The implications of such a civilization are substantial. If the civilization lasted for many millennia, scientific knowledge and technology would be developed. It might take ten or a hundred times as long as if the entire world were full of people developing scientific concepts or engineering solutions to problems, but there does not seem to be a critical mass of people below which science cannot develop. Perhaps there is one, but it might be ten thousand people, and the civilization could be imagined to be larger than this. So, slowly, slowly, technology grows inside this ancient civilization. But because of the limit in population, it would not grow in a wide a domain as it could were the population a hundred times larger. Certain things would be developed, and that field might be explored, and then some time later, a different advance might be made. So, while technology was developing in the small civilization it would not be uniform.

Technology does not develop in a chaotic form, as there are certain advances which have to be made in order to enable the research needed to develop other advances. In our world, genetics had to wait because the technology of DNA analysis was needed first, and it needed computation and some materials developments. In a limited civilization, these pathways would be much more severe. If the civilization lasted only five thousand years, perhaps only some basic chemistry and physics would be accomplished, together with some engineering capability. It is quite likely that working with natural materials like rock of different types would be one that would be developed earlier in the civilization's history. Thus, finding some evidence of precision rock machining is more likely than, for example, asphalt reside from airport landing strips. Carefully thinking out what could be developed in stages might lead to some more clues as to what signatures there could be from small, ancient civilizations.

The challenge of finding such signatures is daunting. Even if someone could come up with a proposed list of them, there is the difficulty of knowing where the civilization lived. In our example, there is only one spot on planet Earth where the signatures would be found. Even if there were two or three, it is still a formidable problem to find them. One could try and figure out where the civilization would choose to be, but that makes the assumption that they searched around over some wide area and picked the best spot and settled there. Starting the settlement seems more likely to be a matter of chance. It might depend on where some proto-humans were when some critical mutation increased their intelligence or when they figured out how to grow a crop on a river delta where they could stay, without continuous migrations using slash-and-burn agriculture. Any number of unguessable things could lead to the foundation of the home valley of the civilization. Thus, it might be necessary to search all river valleys for their location.

It might not have been a river valley where they decided to stay, although that seems a likely choice. A lakeside location is possible. If agriculture was not as dominant as we might guess, a prolific forest area might be a choice. Again, some careful thought is needed to first construct a list of the types of areas that might be chosen, and then to narrow down the possibilities for each. An even greater problem is that this civilization is supposed to have existed tens of thousands of years ago, when the surface of the Earth was a bit different than it is today. So some geology would need to be done as well. This is indeed a difficult problem.

Population and Civilization Age

noreply@blogger.com (Stan Erickson) — Mon, 30 Aug 2021 20:29:00 +0000

It seems fairly clear that if there was an ancient civilization, in the era of ten to twenty thousand years ago, it had a low population. If the population was large, of the order of billions, there should be detectable signatures that we could find and confirm. Resources would show signs of heavy use, cities would be large and numerous, transportation corridors might leave signs in mountainous areas, chemical residues, such as from asphalt runways, might exist in detectable amounts.

Another factor is the length of time the civilization existed. If it lasted a long time, the signatures might have built up and become even more recognizable by today's geologists, anthropologists, and others who search for such things.

In the absence of such signatures, it is a logical choice to assume there never has been any ancient civilization, and any structures or artifacts found today were built by known civilizations. But has there been any serious attempt to find these signatures?

First, consider resources, such as minerals. With a large ancient civilization, resource depletion would have happened, but no survey of the Earth's surface has shown quarries, mines or other marks of resource extraction, to say nothing of resource depletion. Is there any chain of events or choices by the civilization that would lead these signatures to disappear or even never exist? Consider a large iron open-pit mine. The plan for existing mines of this sort includes rehabilitation after the mining is completed and the usable ore has all been removed. Rehabilitation is a process which takes many years, perhaps hundreds. The pit is filled with layers of natural materials, possibly materials added to neutralize any acids which might form when ground water returns to the area, layers of soil are placed over the top and some vegetation is introduced. Any tailings are treated and removed, over an extended period of time. What signatures would exist from such a rehabilitated mine? It should be kept in mind that rehabilitation by a civilization with a longer stretch of experience doing this would be better done and something closer to a natural condition would be expected. If rehabilitation is a process which typically takes a few hundred years to finalize, a civilization that lasts for thousands of years would have seen many cases of it, and would have seen what problems might arise and learned how to prepare for them and possibly prevent them.

Open-pit mining, including both ore extraction and rock quarrying, would leave areas of unconsolidated rock in the midst of a harder, more firm bed of stone. Perhaps some sort of surveying with a ground-penetrating radar might see this. Are there other sources of unconsolidated rock in the midst of a firm bed of unbroken rock? Erosion might produce this, perhaps severe earthquakes could, large avalanches or a cumulation of them might, and undoubted there are others. If this was the only signature, it appears unlikely to be a conclusive one.

Hydrocarbon resources are very plentiful, and show no signs of having been depleted. If coal or crude oil were extensively used by a civilization ten thousand years ago, there is no process known that could restore it. This means that the civilization never went through a phase of such extensive use, or if it did, it was so short that plenty of hydrocarbons were left in the ground by the time that phase ended, or alternatively when the civilization ended. There have been no discoveries of radioactive areas, which might have been formed when a nuclear reactor was decommissioned or abandoned. No features suggesting that there were dams on obvious places along large rivers. Perhaps one or some dams could disappear without a trace, but all of them? So, if there was a large ancient civilization, consuming large amounts of energy, where did it get it? The likely conclusion is either there never was any ancient civilization, or else it was very small in population.

Is it possible that a civilization could develop with a different framework than ours? We have population growth as a constant presence, from thousands of years ago until now. Could a different civilization have made an early decision to control its own population? In the early days of a population, it spreads like an invasive plant or animal. Wherever it can thrive, it migrates. How could some control be instituted that would limit spread and total population? In early days of a society, there is little knowledge, perhaps not even the concept, of population limitation or even a measure of the total world-wide population. Population limitation might develop later in a civilization, at a later stage than the one we are currently residing in, but earlier it would not have been possible, and the reasons that we think about, resource usage and the effects on the environment, are not necessarily things which crop up early in a civilization.

Consider the Mayan Civilization in central America from their earliest villages at about 3900 years ago until the Spanish Conquest five hundred years ago. They built hundreds of cities, ranging in size up to over 100,000 people, and there was no empire, only a large feuding collection of city-states. Most of these were abandoned during the collapse of the civilization about 1200 years ago, and the reason given for this is agricultural exhaustion. The Mayans were very accomplished in agriculture, but when they had deforested the entire area around their cities, a chain reaction of erosion and drought started, which resulted in the cities being abandoned. Severe malnutrition is evidenced in bones found in tombs at this time. This is not the only example of a prominent early civilization being ruined by local changes in the climate, but it is a well-known one, and so might provide some insight into the possibility of a much earlier civilization existing without leaving traces. The Mayans were excellent architects and built numerous pyramid-shaped temples of large size which survive. But they did not recognize over their entire period of existence that overpopulation or rather overuse of agricultural resources would doom city after city to collapse and doom the population to either migrate to a surviving city or return to forest life. Perhaps in Mayan culture there were those who saw the phenomena, and predicted the demise for each city, and they were not listened to or could not be followed for some societal reason. Did they have a Socrates?

Is it possible that an ancient civilization might build a city or two, fifteen thousand years ago, and recognize that their society was not viable in the long term? Could they have decided to limit population in the city to ten thousand and to prohibit the formation of any other cities? It seems like a choice that a population could make, and if it is reasonable that an ancient civilization could do this, then the signatures of such a civilization would not exist or would be renewable so that they were not obvious. Thus, if we wish to ask the question about whether an ancient civilization could have existed, and left a few ambiguous stone constructions as the only signature of their prior presence, we have to assume the population was small, and somehow controlled. Not too small to do engineering, but too small to exhaust resources in a noticeable way. Is it possible?

Ancient Civilizations with Different Cultural Bases

noreply@blogger.com (Stan Erickson) — Tue, 29 Jun 2021 19:57:00 +0000

When we think about the existence, ten or twenty thousand years ago, of an ancient civilization and ask what signs might be left behind, we imagine our own civilization. But there is no reason that an ancient civilization could not have been built around a very different cultural basis. In other words, in the pathway from hunter-gatherer tribes to city-dwelling, tool-using, more civilized ancestors, there may have been a fork in the road. We went one way to get to where we are now, and they went another way. The possibilities need to be explored, or else we will just be out looking for signs of our own type of civilization ten thousand years before but extinct, and miss the signs of a different type of civilization, with knowledge and capabilities similar to our own, but with a different set of foundational rules.

One thing that must be the same is the science. Once a civilization has realized the periodic chart of elements, there are no more elements to be found. The exact same periodic chart will appear, given time, in all civilizations. The same holds for the laws of nature. Newton's laws would not have been named the same in ancient civilizations, but the mathematics which describes them would be the same. Telescopes are the tool of choice for observing the planets and galaxy, and optics is optics in any civilization. Combustion makes heat, which can be turned into motive power, in any civilization. So, the science and the engineering it enables would be the same. A society might be rated as to how far along the line of scientific progress they have travelled. There is some variation possible here, as biology might go a bit slower and astronomy a bit faster in one society compared to another, but there is only so much science, and a civilization which lasts long enough gets it all figured out. We are a couple of centuries from 'asymptotic technology', the point were there are only some small details left unknown, but an ancient civilization might have had cities and science study for more centuries that we have had, and have reached the culmination.

If science and engineering are the same, what can be different? Perhaps nothing is different in civilizations which reach and pass 'asymptotic technology', and the main difference is where a civilization is on that route. This concept is called 'technological determinism' and says that technology is the driver for cultural changes, and when a society picks up some new chunk of scientific knowledge, it will inevitably be changed by it. That means that societies would converge to some final state, not too distinct.

So, we might rephrase the question and ask, where will technology take us, and assume the ancient civilization was there already. We don't know where technology will take us, but it is possible to make some guesses in this regard, as much of technology has been worked out already, and more is being done every year, showing us a direction.

Figuring out where our own society is headed is a fascinating activity, and has been done by many fiction writers, who usually don't have 'technological determinism' and 'asymptotic technology' in their vocabularies. This means they would be very lucky if they are correct, as the fundamental rules by which society develops, at least after the dawn of the scientific method, provide a great deal of information that makes a great deal of difference.

Perhaps we might just ask a more pertinent and relevant question: what would an ancient civilization be like if it left almost no records behind. The obvious answer is 'small.' If an ancient civilization existed, say fifteen thousand years ago, but had only, for example, a half million total population, it would be much more likely that there would be no evidence left behind that indicated they were here on Earth before we were. That might mean three small cities, which could easily have been wiped away by environmental factors.

Does advanced civilization mean giant population? In most science fiction, populations are large. Population has been growing exponentially for hundreds of years, so why would it not continue? The reason might be that an ancient civilization asked itself what population it wanted to have, and the population of that civilization was wise enough to adhere to the answer, and limit or reduce its population to whatever choice was made.

What possible basis could they have had for making some numerical choice as to their own population? Why not ten billion or ten thousand? What kind of reasoning could they have used to fix this target? In our society, population is determined by billions of choices, as each couple decides how many children to have. In an ancient civilization, the same might have been true, but the mode of decision-making could have been different. One factor that could have been in play was the resources on planet Earth. Ten billion people use them up a million times faster than ten thousand. In our society, few people talk about the concept of resource exhaustion or anything else in this subject area, and those who do mention it note that resources are finite and there must be some stopping point in growth, perhaps followed by decline.

One difference between our society and the ancient one could be that they had this discussion much earlier in the population growth curve, and never got up to the hundred million point. This would explain why there were so many easily accessible resources left here for us to find and exploit. If their population had maxed out at a quarter million, there could not have used up much resources by their demise, and therefore we do not see some ancient quarries or remnants of mine openings or spills of petroleum or anything else that would be a signature of a huge population, with a high standard of living but little care for resource conservation.

The next step is to ask, what would a small population do, if it anticipated some catastrophe in the near future, and wanted to leave something behind? Another question is, suppose they didn't care about leaving behind some monument, what might have lasted ten or twenty thousand years which they created and used, not for the purpose of communicating with some new civilization in the future, but just useful for their living or important for their art or whatever else they valued? Since the non-exhaustion of resources is an important clue as to the nature of their society, we can ask about what other features there would be that might have the same origin as this decision.

Of course, another question is, were they from Earth, but that one needs to be put off until later, although an alien colony might have the characteristics we have found to be likely, low population and minimal resource usage. That would mean a modification of the original premise of this blog, which was why we haven't seen any aliens to a whole host of other ones, such as why would an alien civilization form a colony on a planet that was prone to catastrophes?

What Lasts Ten Thousand Years?

noreply@blogger.com (Stan Erickson) — Thu, 27 May 2021 19:21:00 +0000

You can walk around in monuments two thousand years old in Egypt. Archaeologists dig up mounds with relics from five thousand years ago. If we wanted to know if there was an advanced civilization somewhere on Earth ten or twenty thousand years ago, what might be found that could tell us at least where one of its cities were and even better, tell us a little about it?

If the ancients wanted to just let everybody in the future know they had been here on Earth, they might just make a huge block of tungsten, and set it up somewhere so that any following civilization that could identify metal would know that this was not a natural object, and could not have been made by some set of hunter-gatherers. Finding and refining out a cubic meter or ten of tungsten requires some serious metallurgy.

If we assume that the ancient civilization had some smart people, and for whatever reason, they wanted to leave a mark on the planet that they had been there, they would certainly have tried to think through all the possible events that might happen between the time they build their marker, and the time that another civilization would get to be sufficiently advanced to know what it was they were looking at. They wouldn't have thought of building the marker, or cared about it at all, if they didn't have the premonition, or more than a premonition, that their civilization wasn't going to survive much longer. They would have recognized the threat and deduced it was unavoidable. It is hard to imagine an entire civilization disappearing, and we don't have any clue as to what might do that, just some concepts that are perhaps possible. The ancients would be thinking of how to build a marker which wouldn't be engulfed by whatever was going to do their civilization in, and they also had to think about other possible catastrophes that could occur in the inter-civilization period.

Perhaps thinking of an example would make things clearer. Suppose the ancients were good at astronomy, and had noticed that there was an asteroid, far out in space when first discovered, that was going to make a direct hit on Earth, and it was big enough to annihilate almost everything. They had the telescopes to detect these, and had been detecting them for long enough to predict orbits very exactly. This means they might have been at least a couple of hundred years older, as measured from the advent to telescopic astronomy, that we are now on Earth.

Asteroid strikes have happened many times before to Earth and a prominent theory of why the dinosaurs stopped ruling the Earth and gave way to mammals was that a large asteroid hit the planet, landing in the Yucutan or just offshore, producing such a chaos of heat and dust and shock waves and tsunamis and earthquakes and vulcanism and lots more that dinosaurs couldn't survive. Some tiny mammals figured out how to, and they led to us, after another 66 million years of evolution. The asteroid for our example couldn't be this big, as there would be a geological record, but it couldn't be too small either. If it hit the deep ocean, there might not be any crater to find and no clues like the iridium layer that Alvarez found as a signature of an impact event for the Yucutan strike. An ocean impact would flood all coastal terrain, and create a huge amount of hot water vapor in the atmosphere, which would probably mean rain for a long, extended period, almost everywhere. The temperature would rise and stay up for a long time, as the Earth slowly returned to its pre-impact situation, less most life.

Orbits of asteroids vary in their periods, and some of the larger ones go far beyond the gas giants, and take a hundred years or so to cycle back to the near planets. So the ancients might have one or more centuries to plan how to make their marker, and could think long and deep about its preservation for millennia.

One initial question would be: where to put the marker? It couldn't be anywhere near the coast, or inland as far as the tsumanis would reach. It couldn't be inland anywhere that would be washed away by huge rains, which could flow in existing rivers but also might find other paths to the ocean. It couldn't be anywhere where the crust was thin, as there could be volcanos caused by a rupture in the crust from the impact.

Then there is the problem of ten thousand years of dust falling down on it, perhaps burying it. If it was put on a pedestal, that couldn't be too high and thin, as it might be tipped over. Maybe it should be huge, so the erosion of time would still leave something recognizable. If it was huge, it couldn't be made out of a single metal, like tungsten. Maybe there could be a cap of tungsten at the highest point. Rock easily stays around for ten thousand years, but it can't be too ordinary or the follow-on civilization might think it was from some so-far-unexplained natural phenomena. Before they became sophisticated enough to appreciate what the marker was, they might just think it was another opportunity for quarrying. Then the marker would wind up in parts in places that needed defensive walls, or temples of rock, or anything else extremely solid. Many archeological sites have been victimized by humans, in recent centuries, who had no interest whatsoever in preserving the past but a great interest in finding things that could be sold or used for their own purposes. Incan sites have been especially victimized by those bent on re-use of good materials.

One way to prevent re-use of the marker monument rocks would be to make them too big for a second civilization to use in its earlier period, before they became sophisticated enough to appreciate the preservation of ancient structures. They could also make them into something that could be re-used itself, or added to for re=use, rather than disassembled and carted off. Perhaps they would try to make their monument impressive, with giant statues of solid rock, so that the new civilization would think twice about abusing it. A new civilization might then try to make use of the monument for some purpose, like a temple or a royal palace or something else, and the new monarchs might even claim they had produced it, rather than found it after millennia of being ignored and abandoned. Perhaps a block of tungsten or titanium is the wrong approach, and something that caters to the likely situation in the new civilization's early years would be better. Writing on the monument might be fruitless, as the new civilization will need a long period of development before writing is established and they recognize what those markings are. So, a simple monument, made from large whole rocks that were of the hardest kind that could be used, perhaps with some statues, might be the final choice of the ancient civilization as they faced their doom.

Maybe there might be some remnant of their cities, or vacation spots, or ports or something else which survived the catastrophe and the following millennia, while the few remaining humans went through a return to prehistoric living conditions and gradually re-invented civiization. Sounds like some excellent archaeology needs to be done, and some careful scrutiny to make sure a misclassification does not occur.

Why Now?

noreply@blogger.com (Stan Erickson) — Sat, 01 May 2021 17:40:00 +0000

Asking the question about whether there could have been a more advanced civilization of humans that was eliminated in a catastrophe, or related questions, leads to some deeper ones. Why did intelligent humans evolve at the time they did? Why didn't we evolve into city-living, culture-appreciating, educated, adept, clever humans two hundred thousand years ago? What delayed our approach? Why weren't we delayed another hundred thousand or two years? Why now?

One way of looking at this is to examine the preconditions for the final leap of evolution, to thinking brains and everything they required, and see when they arose for the first time. The simplistic solution is to just make a list, accurate as possible, of what steps led to humans and see why one of them couldn't have happened earlier.

One detail needed to follow this approach is to decide just where on the taxonomy of animals intelligence could have arisen. The pat answer is that we needed thermally regulating bodies so our brains didn't turn off in the winter. Why is this true? What about evolving in a region with fairly constant temperatures over the year? Perhaps it is a day/night temperature difference that excluded reptiles from becoming intelligent. Suppose some lizard had a complex brain, but could only think during the day when temperatures were warmer; why is this an impossibility? During colder temperatures only the lower brain stem, which is what today's reptiles have, was working. That part would allow the reptile to live like other dumber reptiles, except when temperatures got warmer, and then it could think great thoughts.

If we cannot determine some incontrovertible reason why reptiles couldn't have become more intelligent, the boundary of time when intelligence could have started is pushed back, hundreds of millions of years, when, supposedly, reptile species ruled the entire planet. We should ask: what good would being able to think more complex thoughts do for a reptile? Their ability to survive and reproduce depends on their visual skills, their speed, their ability to recognize hiding places, their ability to capture prey using body and head muscle linkages with eye coordination, and perhaps a few other things. Nowhere in this list is anything that a complex thought might help. Compare that with chimpanzee-like species which could begin to use found objects and then shaped objects as tools. Tool-using elevated species from chimpanzee level to human level. Current eptiles don't have the physiology for that.

So, could we have reptiles of millions of years ago, those who were living in forests, take an evolutionary jump to climbing trees and developing opposing thumbs and dextrous hands? If evolution could do this, why not, over another million years of evolution, could they not develop thermal regulation to some extent? Thermal regulation requires energy, and could reptiles become better hunters or more complete omnivores, and simply follow the pathway to intelligence that proto-chimpanzees would follow millions of years later? Why weren't the steps needed for intelligence, whatever they might have included, completed long ago, in the millions of years scale.

Perhaps evolution couldn't make the total number of jumps needed for this, simultaneously. Was the jungle many millions of years ago more hostile to the growth of intelligence that the forests of a few hundred thousand years ago? What about hands? Some animals climb trees using their claws, which penetrate into the bark or catch on irregularities in the bark of trees, and evolve so that this method improves, as opposed to developing grasping hands, which is a totally different evolutionary path.

Without grasping hands, evolution couldn't take one of its sideways steps. A sideways step in evolution is when a species either mutates its genome by moving one section to another place, perhaps copying it there, which then allows the species access to some new capability, not related to the one for which the genes had evolved for. We can think of the software side of evolution, which is what happens when one generation imparts some wisdom to the next one, which allows the newer generation to use its mental and physical capabilities in a task that it wouldn't have, without the training.

What else in evolutionary pressure serves to force hands to develop? If the species lives on fruits and other pickable objects, hands might be useful here. Alternately, if the animal simply eats leaves and flowers for nourishment, then hands don't play much of a role and wouldn't be selected for in the evolutionary process. Fruit provides more concentrated nourishment that leaves, as do seeds and some roots. Was food selection the problem that kept reptiles from becoming intelligent millions of years ago?

This doesn't sound correct. Why couldn't reptiles evolve to eat fruit and seeds, if primates could? Were there fruits around millions of years ago in the equivalent of forests?

Perhaps the question should be asked in a completely different way. How do we know that some lizard species did not develop intelligence of some sort two hundred million years ago? Would there be anything detectable this many years after they became extinct? Perhaps the intelligent lizards lasted a million years and build cities. What kind of rubble lasts two hundred million years? Do we know how to do excavations to figure out the answer to this question?

One thing we do have is fossils. Fossils occur when some animal does some stupid thing and gets caught in some mud and dies and then the mud turns to stone. Because of some perversity of nature, braincases are not often found in fossils. But recently some have.

To be intelligent, one needs a large brain, measured in terms of brainweight to bodyweight. Some recent finds of reptiles raises the possibility that some of them may have larger brains that has been expected by the earlier-discovered fossils. If we assume that civilized reptiles two hundred million years ago managed to largely avoid getting stuck in mud pits and turned into fossils, then their absence in our dinosaur skeletal displays in the different natural history museums around the world is understandable.

What else might be left behind from a civilizatin of intelligent creatures that lived for a million years and died out two hundred million years ago? What might get buried and refound that would last two hundred million years? For early human civilizations, we look at burial mounds. These are put together in the first few thousand years of civilization, and then everybody stops doing it. Inside these burial mounds there are gold ornaments and jewels, which might be contenders for enduring the forces of nature for millions of years. Would a civilization that lasted much longer not simply collect these things from their own archaic burial mounds and put them in a museum? And since the Earth changes its profile in much shorter times that two hundred million years, moving dirt and rock and lava and water and any materials around on the planetary surface, how could we expect anything from an ancient city to survive. Maybe they invented materials that were more durable than concrete? Concrete might be good for tens of thousands of years, if no earthquake or flood gets to it. What is left after a short time such as a hundred thousand years? Rubble. Maybe there might be some chemical test to see if some rubble we find has some unique features? Rubble near the surface probably wouldn't stay in one place, however.

One thing we can detect for long periods, in very unique situations, is the materials embedded in layers of rock. That is how we suspect a large asteroid hit the planet some 65 million years ago, from the thin layer of iridium-rich deposits all around the world. Would the lizard civilization have put something into their air which would be detectable? It is very hard to think of any possibilities in this area.

The conclusion is beginning to look inescapable. There is no way to tell if we are the first intelligent species to emerge on Earth. All the hubbub that goes on about aliens on other planets coming to visit us might be expanded to ask if there were some 'aliens', of the homegrown variety, right here already. If it could have happened once, maybe it could have happened twice or more times. All of these things would leave no evidence. One result of realizing we might be the tenth intelligent species on Earth rather than the first is that we really don't have a good understanding of evolution yet. Maybe there are clues buried in the genomes of the organisms of Earth that indicate something intelligent was around a very long time before us. It is certainly not clear how this might happen, but we need to grasp at straws to answer this question.

Ancient Civilizations

noreply@blogger.com (Stan Erickson) — Sat, 17 Apr 2021 20:09:00 +0000

Common belief here on Earth is that our civilization has been continuously improving since the human species came into existence. It has been a steady sequence of more population, more technology, more areas inhabited, more organization, more culture and so on. With that as our history, it is easy to project onto possible alien civilizations on exoplanets that they too had a uniformly improving history. Then some comparisons can be made, some calculations, and some predictions. That has been the basis of this blog.

What if this is all wrong? What if there have been one or more civilizations on Earth which were wiped out by one or more catastrophes? There are at least two questions that immediately spring up. One is about the evidence that might indicate this is at least possible and not ruled out by everything archeologists, geologists, and other scientists have collected and interpreted. The other is, provided the answer to the first is that the evidence for the simple single rise of civilization is not wholly compelling, what does this mean about potential alien civilizations? If our planet had one or even a series of catastrophes, wiping out mankind down to the hunter-gatherer level, and then mankind built up a following civilization virtually from scratch, maybe this happened on exoplanets as well.

Why even consider this? There are some scientists and others who see something in the evidence available to us, overlooked to date, which indicates the progression of society has not been wholly linear. They noted that the level of the oldest stonework at a few sites appears to be significantly more capable than later stonework. They raised the possibility that there was a retrogression of technology at least once in the history of humankind. Instead of a fruitless discussion of the arguments involved, just suppose that it is a possibility. We might first ask what kind of catastrophe might destroy civilization but not lead to species extinction, not for humans or for any other noticeable species. Is there even a possible phenomena which could wipe out civilization without ending the human species?

To be able to completely collapse after such an event, totally but not permanently, means that civilization is much more fragile that has been appreciated before. This fragility needs to be understood in terms of the civilization that existed at the time of the catastrophe. That civilization might have taken some different paths that made it more vulnerable that ours is. Or perhaps we underestimate the fragility of our own civilization. What could wipe out our civilization so that only hunter-gatherer tribes were left? Are there any unique events that could do this?

There are natural catastrophes, like volcanoes, and human catastrophes, like a biowar which targeted food crops. The list of natural catastrophes is quite well-known, as only a few things could affect mankind world-wide. Ice ages could top the list, as there have been several major ice ages, and many more mini ice ages during the non-ice-age intervals. The causes of ice ages are not conclusively determined, but that is of no consequence to the determination of their effects on a civilization. Perhaps one of the most interesting factors is the albedo of ice. Since it is higher that that of uncovered dirt, vegetation, or ocean water, that means that if something happened to increase the fraction of Earth covered by ice, then the amount of heat received by Earth, in total, would decrease, and it would cool down more. This is a positive feedback loop, and could go either way. Orbital variations might be the trigger for this rapid change. The large gas giants affect the orbit of Earth, as an example, and change its eccentricity, and perhaps other parameters. If we look at the collection of possible Earth orbits over the last billion years, we would see there is a distribution, perhaps a bell curve, of the insolation averaged over each year. If the orbit of the Earth was at one end of the distribution of solar energy intercepted, the end where insolation was largest, the climate could snap from ice age to minimal ice in a short time. At the other end of the distribution, it could snap the other way. 'Snap' might mean less than a thousand years or even less than a few hundred.

Ice melting on such a vast scale changes the sea level depth by something of the order of a hundred meters. If civilization had adopted mostly coastal cities, they would be wiped out in short order. Perhaps this is one candidate for a civilization-terminating catastrophe. Even a lesser amount of melting might drown most cities. Would this end civilization?

What would happen to a civilization similar to ours if such an event were to happen? Perhaps over a few centuries, most cities would be inundated. People would have to move to higher ground. There is no question, at least on Earth, that there is bare land available for cities, but the benefits of the locations of the previous, now flooded, cities would not be available. These might be ports. A tremendous amount of our trade is by ocean transport. New ports might be available when the seas stop rising, but during the period of continuous rise: no one would be able to build a port which might be flooded in a few more years. So transportation would be seriously affected.

The costs of building new cities would be very large, and perhaps enough to overwhelm the economy of Earth, or of any comparable civilization of aliens on an exo-planet with a similar ice age phenomena. Would the economy crash, or just degrade enough so that science and technology would be preserved, and the living standard would only decline a moderate amount, not entirely down to hunter-gatherer level.

Some of this land would have been agricultural, so some food production would be lost. Many countries would be little affected, and others very seriously affected. Would this mean massive migration? Would it mean wars fought over who would control the remaining good land? On top of the possibility of the economy crashing or at least declining significantly, there is the possibility of war, where the holders of good land attempt to stop huge populations of those from inundated lands entering and taking it over. War might not be local, but in many different places, almost at once. If a faltering economy did not cause enough damage, widescale war on top of it might, and here is a possible scenario for a collapse of civilization.

There are many other questions related to this issue, but they deserve a separate post.

Detecting Alien Civilizations

noreply@blogger.com (Stan Erickson) — Fri, 21 Aug 2020 03:11:00 +0000

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.

Aliens in Binary Star Systems

noreply@blogger.com (Stan Erickson) — Sun, 16 Aug 2020 15:32:00 +0000

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.

Nearby Black Holes

noreply@blogger.com (Stan Erickson) — Fri, 14 Aug 2020 15:14:00 +0000

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.

Heavy Elements in Galaxies

noreply@blogger.com (Stan Erickson) — Wed, 17 Jun 2020 21:20:00 +0000

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.

Futurology and Alienology

noreply@blogger.com (Stan Erickson) — Mon, 15 Jun 2020 16:15:00 +0000

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.

War and Technology Development

noreply@blogger.com (Stan Erickson) — Sun, 14 Jun 2020 16:07:00 +0000

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.

Geological Separation on Exo-Planets

noreply@blogger.com (Stan Erickson) — Sat, 13 Jun 2020 16:10:00 +0000

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...

Can Bioterrorism End Alien Civilizations?

noreply@blogger.com (Stan Erickson) — Sun, 03 May 2020 15:10:00 +0000

'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

noreply@blogger.com (Stan Erickson) — Sun, 03 May 2020 15:01:00 +0000

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

noreply@blogger.com (Stan Erickson) — Sun, 03 May 2020 14:54:00 +0000

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

noreply@blogger.com (Stan Erickson) — Sun, 03 May 2020 14:46:00 +0000

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?

noreply@blogger.com (Stan Erickson) — Sun, 03 May 2020 14:37:00 +0000

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.

Peak Technology and Asymptotic Technology

noreply@blogger.com (Stan Erickson) — Thu, 26 Mar 2020 20:33:00 +0000

To avoid confusion about the definition of these terms, both of which are important in alienology, it might be useful to clarify them here. Peak technology is what happens when an alien civilization runs into a problem, and is unable to sustain the growth of its scientific knowledge. Problems might be some catastrophe that causes shortages, like the alien civilization's bad luck to be on a planet with minimal resources, and try as they might to use them sparingly, they run out before they get to a complete knowledge of technology, a point which is called asymptotic technology, and their civilization begins a downturn. Science begins to be forgotten, or becomes unusable. There might be knowledge preserved in some sort of records, but there are too few people around who can learn it, so, as far as the whole society goes, it is forgotten. To use an extreme example, a planet with only agricultural villagers remaining after a golden age is one where peak technology has come and gone, no matter what type of recordings of past scientific knowledge there is locked away in some vault in a cave.

Problems can arise from external sources, such as the famous example of an asteroid impact which is large enough to cripple the civilization and prevent it from recovering; the population is reduced below the critical mass needed to maintain technology, let alone progress in it. Problems can arise from internal sources, such as if biological terrorism leads to the extinction of a large fraction of the population. There are a host of other examples in each of these categories. An encounter with a passing star, enough to alter the orbit of the alien planet is one; the star does not have to get so close as to throw the planet out of its solar system, just close enough to make the orbit more eccentric, so that the whole land mass is covered with ice during aphelion, and it doesn't melt during perihelion. A supernova sufficiently close could do it. Basalt flooding could do it. Incessant war could do it. The desire of a ruling elite to maintain itself, coupled with a fear of social change due to more technology could do it. Even persistent, extreme affluence might do it.

When a civilization suffers a problem such as this, not all technology is forgotten. Depending on how severe the collapse is, there might only be agricultural expertise left. Or transportation equipment at some level might be maintained, depending only on whatever original resouces are left plus renewable ones. The general idea is conceptualized as this graph:

There is no need for the curve to be smooth; it could just as well be bumpy at any section of it. The duration of time that the civilization spends near peak technology is a function of its population, the planet's natural resources, and many other factors. The slopes of the two sides might be of the same order, or they might be different: for example, the rise might be quite steep, as technology's rate of change feeds on itself, but the loss of technology can be slowed by the struggle to maintain it as long as possible.

If nothing goes wrong, technology just keeps accumulating until there isn't any more that isn't known. This is a very finite process. Sometimes someone makes a comment that implies that technology keeps accelerating forever, but this has no meaning whatsoever. Knowledge of details, such as how much sand is on some beach on some exo-planet, might be accumulated, but data is not science or technology. Science is a matter of understanding how the universe operates, and there is certainly some data involved in it, but it is largely a matter of theories explaining phenomena, patterns that exist, cause and effect relationships, and other things; in general it is the compaction of the ability to explain things that happen or that exist. The compaction starts with generalization which often grows into quantitative expressions describing almost anything.

Asymptotic technology speeds up as early theories are found and validated, which allow more general questions to be asked. At some point, all the easy concepts are found, and the remaining ones grow harder and harder to develop. Thus, the curve of technology looks like an exponential during its earliest phases, and then tips over and continues to slow in its rate of progress, towards an asymptote of total understanding. This is a description of the general form of the technology-time curve, which looks like this:

The height of the asymptote is always the same, for every alien civilization. It is complete knowledge of science and technology. This simple fact is critically important for the study of alien civilization, in absentia. The coupling is done by the principle called technological determinism, which says that technology dictates the forms that a civilization can take, and since the asymptotic technology for every civilization is the same, the form of all the different alien civilizations in the galaxy will have very much in common. If we can understand how technology will progress, we will have an important tool for the study of all alien civilizations.

One aspect of technology that assists in the understanding of its eventual progression is that technology builds upon itself. Different areas of technology do not progress at the same rate, but instead, one area will go slowly until another area has passed some threshold where the second area can facilitate progress in the first. Thus, technology evolves in stages, which means that the forms of societies will also go through stages. The most all-encompassing of these stages might be called grand transformations, and these appear to involve, in approximate sequence, fire-making, wood and stone use, agriculture and husbandry, metal use, fossil fuel use and the industrial consequents, electronics and its end-effect of artificial intelligence, genetics and psychology and then interstellar space flight, if the civilization is up to it.

Each of these stages might take different amounts of time to come to full blooming. It might be possible to understand them all separately, using the same model of asymptotic understanding. Early learning is relatively faster than late learning. This means that the middle portion of alienology, after the planet-building and origination and evolution of life and before interstellar travel, where civilization develops, has some principles that can be used to gain insights. This is one of the fundamental bases of this blog.

Does the Drake Equation Make Sense? Part 2.

noreply@blogger.com (Stan Erickson) — Thu, 06 Feb 2020 02:04:00 +0000

If life originates, and the planet where this happens continues to reside in the liquid water zone, does it evolve to intelligent life? Are there certain conditions which are prerequisites for intelligence to evolve? Would they be common among such planets, or rare?

In this blog, and certainly elsewhere, it is supposed that tool use, starting with fire, then stone and wood, leads to the increasing capacity of the brain of some dominant organism. An equation, similar in form to the Drake equation can be written for this process, involving the evolution of increasingly complex organisms, starting from the first thing to form which constitutes life, a membrane enclosing some proteins that reproduce in some way, and which also produce more membrane. The steps might include the formation of more complex cells, with different features, the ability to exist in different environments and to consume different chemical energy sources. Then the shift to multicellular organisms has to happen, and many steps of evolution might be inserted into the new formula for the progressive development of capabilities of multicellular organisms. Then, back to single celled organisms, a step has to exist to be able to take energy from photons from the star, with the development of some primitive form of chlorophyll. And it goes on and on, as evolution is a horrendously complicated sequence. Regrettably, we do not understand the sequence completely, not even the conditions on the surface of the planet which are required to allow them to happen. The overall probability of producing intelligent species might be 1.0, meaning inevitable, or 0.000001, meaning intelligence is not a particularly useful capability for most creatures on an exo-planet.

The rise to intelligence is perhaps the most difficult of the probabilities in the Drake equation to estimate, as the evidence of most forms of life does not last for billions of years, with only a few exceptions. It should be one of the first orders of those who study it to come up with the new sets of probabilities, so that these can be studied from a normative sense, and then the whole combined into the Drake factor measuring it.

From intelligence to a civilization, mastering technology up to electronics, is another opportunity for sub-probabilities to be estimated. Here it is much easier, as there is history of our development, and it serves as one example, and a base upon which tangents may be followed. This blog includes, in many of the posts, speculation on the steps involved. There seems to be a natural order by which technology progresses, one stage depending on the previous, and there also seems to be a drive, reminiscent of evolution, which pushes creatures to develop successive stages of technology. Figuring out the steps up to the stage of civilization that we currently inhabit is not so difficult, but the postulation of what happens next is extremely controversial. There seems to be a tendency among modern-day humans to forecast dooms that might be imminent, and if one such doom really exists and is universal among intelligent species, reaching broadcast capability might be chancy, and staying there more chancy.

Another of the assumptions inherent in the Drake equation is that broadcasting is the end point of technology, and it would continue for some long period. It hasn't. There is still some, but the term, L, in the Drake formula may be very short as better ways of shipping large quantities of information around the planet have been found and have displaced broadcasting. This seems likely to continue, so L may be, for us, less than a hundred years. With that short a time, being so lucky as to be listening during the particular century out of billions of years of planetary existence is almost impossible to expect.

The Drake equation, if used with the retrospection of all the decades that have passed since it was first written down, may well indicate that the SETI project is hopeless and should never have been attempted. Many people's lives and careers were involved in it, and certainly some, perhaps many, were overwhelmed by the feelings that if they were successful, their fame would be writ large on the pages of scientific history. Some of the participants talked about the success of the project being a grand changer of the direction of human civilization. With such a result, it is not hard to see how the Drake equation was mis-evaluated in many ways so as to provide a justification for the search. Who wants to have their hopes of a glorious legacy be dashed?

The Drake equation, and indeed the SETI project, did have the value of focussing the attention of many individuals, scientist and non-scientists, on the various steps in the formula. It raises the interest level and provides some motivation for doing the hard scientific work necessary for our continued progress. There is little work going on in some very important areas, such as questions of the origination of life, but there might be even less if the burst of energy and excitement that the SETI project ignited had not happened. Understanding evolution is a continuing scientific task, and it might not have been greatly affected by SETI's popularity, but perhaps as the gaps and uncertainties in Drake's formula become more clear, there will be some effect, and some new Darwins will enter the field and erase the dark gaps in the theory.

Mankind has always tried to understand history, and the nature of man and the nature of civilization, but the Drake equation takes all this non-scientific palaver and demands that it be turned into a quantitative measure of how civilization develops. Historians typically do not make much use of the theory of technological determinism, which says that civilization is forced to adapt to technology, which is forced to follow a certain pattern of temporal stages. If history becomes scientific, this might be the result of the Drake and SETI activity with the greatest influence on the future of humanity. Once history becomes more scientific, a better forecast of the potential futures can be given and we would not have to resort to choosing between a dozen different predictions of dooms.

To summarize, the Drake equation inspires work in the following areas: orbital stability for small rocky planets, origin of life from either a unique event or ordinary conditions, the evolution of life through the millions of steps needed to lead to intelligent creatures, and the transformation of history from an art to a science. With the retrospective understanding we now have, the probability of success of the SETI project likely starts with many zeros, and there does not seem to be any redeeming factors in the equation which would raise it even to the order of a few percent or more. Given the amount of effort that was put into it, it was a good start, insofar as it provides motivation for more good science, and also makes non-scientists aware of the possibilities that we are not alone, and with a good amount of further work, we might know just how not alone we are.

Does the Drake Equation Make Sense?

noreply@blogger.com (Stan Erickson) — Thu, 06 Feb 2020 02:03:00 +0000

The Drake Equation was developed in the infancy of the SETI project. The Search for Extra-Terrestrial Intelligence was a US-sponsored project starting over sixty years ago, designed to listen for any kind of electromagnetic broadcasts than another intelligent civilization might be emitting. The equation is simplicity itself, just a product of conditional probabilities. Here it is:

N = R_*^.f_p^.N_e ^.f_l ^.f_i ^.f_c ^.L

and N is the number of detectable alien civilizations in the galaxy,

R_*is the rate at which stars form in the galaxy,

f_pis the fraction of stars which develop planets,

N_eis the number of planets within a planetary systems which have the right conditions for life,

f_lis the fraction of planets with the right conditions for life which develop life,

f_iis the fraction of planets which develop life up to the level of intelligence,

f_cis the fraction of planets with intelligent life that build systems to radiate electromagnetic waves,

L is the length of time such civilizations persist in their radiation.

There are a number of assumptions made which permit the formula for N to be expressed this way. Let us discuss a few of them.

First, the Milky Way galaxy is chosen as the basis for measuring everything. We only know that life can originate on a spiral arm, far away from the bulge and the black holes which inhabit the center. It seems quite reasonable that life needs billions of years to evolve to the stage where a civilization emerges and starts emitting radiation, and in the bulge, distant stellar encounters happen much more frequently than in the spiral arms. A stellar encounter can create a gravitational pull on a planetary system to disturb it, and a planet which had conditions for life prior to the encounter may be moved either inward or outward relative to its star, where the conditions do not hold. Two solutions might be done for this, either change R_*to only count spiral arm stars or modify all the subsequent probabilities to take into account the different conditions between the spiral arms and the central bulge.

Second, the term detectable can be defined a number of ways. Since radiation dies off as the square of the distance travelled, without absorption, and worse with absorption, does detectable mean detectable with some particular equipment? Imagining a ten kilometer aperture radio dish out beyond Neptune's orbit, and compare that with the original SETI equipment. If one wants to be able to detect a civilization's emissions from the other side of the Milky Way, assuming the central bulge does not intervene, something huge would be required on both ends.

Third, the equation seems to be assuming roughly isotropic radiation, spreading equally in every direction, including the one direction that heads toward Earth. Why would any civilization do that? There might be some transitory period when they were broadcasting for their own planetary uses, but if they wanted to communicate from solar system to solar system, they would develop a narrow beam system that would require only a tiny fraction of the power of an isotropic radiator. But then detectable means that Earth is in the beam of such a system. That would be rather fortuitous.

Fourth, the fraction of stars which develop planets might be, as we now know, approximately one, but developing planets does not mean life can evolve on one of them, or certainly not to the threshold of EM emissions. Stars heavier than our star burn out quickly, and if one included them in the count, they could have planets and one could have the right conditions for life, but these conditions would soon change as the star evolved and died. On the other end of the scale, M dwarfs, the most populous kind of star, doesn't have enough energy output to have a planet with the conditions for life, except if it is close in, and there it would be likely phase-locked, with the same face always directed at the star. There are good objections to assuming life could evolve in such a system.

For the mid-range of stars, where our sun resides, there might be planets, and one or two with the conditions for life, but we know little about the migration of planets, even without the evolution of the parent star. Do smaller planets keep their orbits for billions of years in any planetary system, or does it take billions of years for them to gradually migrate inward or outward? If we change the definition to having a planet of the right size in the liquid water zone for billions of years, the number might drop from about 1.0 to 0.00001. Figuring out long-term stability of orbits should be a fairly simple task for the current state of mathematical astrophysics, but it does not seem to have been done in a comprehensive way that enables on to figure out this term in Drake's equation.

Fifth, exactly what does the “conditions for life” entail? If it is made very loose, the corresponding probability would be high, and the subsequent probability would be less to make up for the looseness. If it is made tight, the inverse happens. At the time the Drake equation was written, mankind did not know how life forms, nor what were the conditions needed for it. Now, sixty years later, the same situation exists. We don't know. It is appalling that so little work is done on the origination for life. One particular question is that, are there some conditions in which life forms over a period of time, something large compared to human lifetimes but small compared to solar lifetimes, like a million years? Or is the situation completely opposite, life only forms if some event happens, and the probability of the event might be very, very small.

Just suppose, as hypothesized in this blog, a mild collision with a large planetoid, which becomes a satellite, is necessary for life. The collision would have occurred in the early part of the solar system's existence. Earth-like planets which did not have that collision in their history might be similar in many conditions to ones which did, but, if the hypothesis is correct, only the latter could have life. There are certainly other events in the history of a planet which might affect the origination of life, such as the chemical composition of the crust, volcanic heating, and asteroidal bombardment.

To be generous, life originated three or four billion years ago, and we do not know the conditions of the Earth's surface, so we are limited in imagining how life could originate. The delay in life origination work might be caused by the delay in planet origination work. Neither is in a good state. There is no reason to think that current conditions on the Earth could lead to an origination of life, assuming all consequences of life were removed. One of the conditions discussed in this blog is the existence of organic oceans on the surface, able to nurture membrane formation as well as complex protein formation. Where might they come from? The mild collision hypothesis is a possibility for this.

Chromosome Genetics

noreply@blogger.com (Stan Erickson) — Mon, 27 Jan 2020 21:23:00 +0000

Knowledge abounds here on Earth about the number of chromosomes humans have and how gender is determined by whether a fertilized egg cell has an XY or XX chromosome pair. It's less well known that cell division includes the opening up of all nuclear DNA pairs and the splitting of them into two batches before replication. Even less well known is how hard it is, given today's technology, to separate chromosomes so they can be accessed individually.

It is not exactly clear if there is any other way of harnessing the protein synthesis control capabilities of DNA so that alien cells might have a different way of doing it. Nor even is it known if there are alternatives to DNA to carry genetic information. Genetics in this area is like exo-planetary studies before any exo-planets were discovered. Everything is speculation.

These two questions are somewhat independent. If an alien planet had non-DNA genomes, that still does not mean that they would not have all the genetic information divided up into chromosomes. The alternatives are to have more than one nucleus in the cell, with perhaps one chromosome in each, or to have one nucleus with only one chromosome pair having all the DNA or its equivalent. Why did Earth evolve multiple chromosomes, or rather, why don't all species have just one large circular chromosome as do many single-celled organisms? What is the evolutionary advantage and would it be universal, meaning on other planets as well?

Among contemporary bacteria, there are some with one, two or more circular chromosomes, some with linear chromosomes, and some with a combination. After billions of years of evolution, the competition for a chromosomal shape has not been won by any arrangement, so for bacteria and other prokaryotes at least, there must be little evolutionary advantage between them. This is not true for eukaryotes, multi-cellular organisms, which all seem to have linear chromosomes. Most eukaryotes also have some legacy circular chromosome material, located in the mitochondria or elsewhere, which reproduce independently of the nuclear DNA during cell division.

One advantage is obvious. To have genetic information for many different types of cells, as well as the signaling information for organizing them, there must be much more information, and a circular chromosome or a single linear chromosome with all this information would simply be too large to fit into the nucleus, or for the meiotic proteins to handle. Having everything in large numbers of diverse mitochondria also seems evolutionarily difficult, for the organization of cell replication. So, using DNA or anything else, it appears likely that alien species will have multiple linear chromosomes.

Alien geneticists may run into the same problem that Earth geneticists have: separating chromosomes is difficult. The processes within the cell are quite complex, and there is not enough information on them to allow them to be replicated or imitated in a genetics lab. Neither have there been any simple mechanical solutions to separating chromosomes. Perhaps we are missing the right discovery. By the time asymptotic technology arrives in the genetics area, however, this problem will have been solved.

It's not clear that the ordering of advances and inventions in the genetics grand transformation will make much difference in how an alien civilization will develop. The end result would be the same. But chromosome separation would allow some cost-savings in making genetic changes to organisms, or to the creation of synthetic organisms. If this cost-savings is large, it would emphasize the possibility of having genetically modified or created organisms throughout the civilization.

All we can do now is map the genome of humans and other organisms, and use that information for diagnoses, or in plant and animal breeding. There is some work being done on inserting novel genes into existing plant and animal genomes, but it is very slow. If it were possible to isolate chromosomes rapidly and inexpensively, this would speed up the process. It would also make the process of genetic modification more certain, as a laboratory could simply work with one chromosome and modify it, without having to worry if the modification methodology would accidentally make a modification in another chromosome, with a similar stretch of DNA.

One interesting question to ask is how would an advanced alien society prepare the genetics of their successive generations of their population. Suppose there is an inexpensive way to separate chromosomes. Then, the alien society could simply decide to choose the best set of chromosomes from the copies available. If there is some optimal set, then all the aliens in later generations would be like clones. Alternatively, if the selection was out of the set of a pair of parents (assuming two genders), a wide variety of individuals would remain, but there would be a trend toward more healthy individuals with better capabilities.

Similarly, if there were pairs of parents with some genetic deficiency in one chromosome, specifically in one of the parents, then that chromosome could be eliminated in the resulting next-generation individual. This would result in the gradual elimination of genetic diseases and other problems, although errors in replication remain possible and there would always be a risk of some new mutation arising.

There are many syndromes which arise because of the improper copying of whole chromosomes, meaning extra copies, and with chromosome separation technology, these would be reduced or eliminated as well. Broken chromosomes could be sorted out as well, and mutations arising from copying errors would be detectable and removable. Reading the genome would be less computationally intensive and less prone to mistakes, if each chromosome was read individually. The current Earth method of batching all the chromosomes together and then sorting them out after all the fragments have been read is clearly something that can be improved on.

The technology to separate chromosomes does not seem to be on the horizon, meaning the old methods would be used here for a decade or so. Microbiological investigation into how to make a cell nucleus separate and then how to create microtubules to reach into the mixture and connect to individual chromosomes needs to be done. Once it is well understood how nature accomplishes this task, it would be more reasonable to expect that genetics laboratories can come up with some combination of biological and physical equipment to accomplish chromosome separation. After this, we might see genetics jump forward very fast in potential applications, and this will give us a much clearer idea of what an advanced alien society might be doing with their own technology in this area.

Mineral Planets

noreply@blogger.com (Stan Erickson) — Fri, 17 Jan 2020 19:07:00 +0000

Let's use the term mineral planet for planets that an alien species could turn into a sustainable habitat. These are a far cry from an origin planet, which is one which could give birth to life by evolving its own first cells. It is a far cry from a seedable planet, which is one which could not evolve its own starting cells, but which could take a seed of some sort of cells and have them multiply and eventually evolve into something interesting, like an alien civilization. Instead, a mineral planet is one where an advanced civilization could establish mines and habitats, on the surface or below it, and thereby produce enough resources, energy and minerals, to sustain an alien colony without any continuing support from the home planet. It has to persist for a long period.

There may be very few origin planets in the galaxy, and somewhat more seedable planets, and maybe a huge number of mineral planets. One implication of such a lopsided ratio would be that mineral planets can be stepping stones for an alien civilization to cross the galaxy. Note that some or all alien civilizations may adopt the goal of seeding as many seedable planets as they can, following a philosophy that life is its own goal, and that just like planet-bound species try to disperse as much as they can, alien civilizations try to spread life as much as they can. Traveling 300 light years from a civilization's origin planet to the nearest seedable planet might be simply too much to do, and so finding a network of mineral planets in the general direction of that seedable planet would allow them to gradually work their way over to it, and when close enough, to accomplish the seeding effort with more payload and duration in orbit that they could have if they had to travel 300 light years.

Reliability might play a role here. If a speed of 1% of the speed of light is used as a guess of the maximum speed the civilization might attain with its colony ships, this means 1000 years of reliability is necessary to go to the nearest mineral planet, but 30000 years would be necessary for the closest seedable planet. If the probability of enough equipment lasting 1000 years can get raised to 98%, a risk the civilization might be willing to take, the same equipment has a probability of the same quorum still working after 30000 years of travel of only 55%.

Monitoring a seedable planet is also easier from 10 light years away than 300. It might be that seeding a planet is necessarily a very chancy situation, and multiple visits are the only way to accomplish it and verify that it has been accomplished in such a way that a billion years of evolution or two can follow without total extinction. Maybe seeding can only be handled by landing a small colony on the planet, and staying there for a long period. This could also be accommodated better from a nearby solar system than from a distant one.

Is there anything which can be credibly said about the prevalence of mineral planets? The formation of stars seems to leave a disk of matter revolving around it, which can turn into planets. This is a matter of the disposition of angular momentum, and how hard it is to collect it all in a central body. Everywhere we look we see planets, and our ability to find them is not so great right now, so there are probably many more per cubic light year than we have discovered in our locality. If there are several planets on the average per star, how likely is it that at least one of them is a mineral planet?

To be a mineral planet, the planet has to be mineable and habitable. Planets too close to the star are too hot on the surface to establish a colony, and the temperature below the surface would be higher than the average temperature at any latitude. The orientation of the planet would indicate the spread of temperatures over the planet, from pole to equator, and indicate if there was any latitude above which a colony ship could land and stay without thermal damage. Phase-locked planets provide a different criteria, but if the north pole of a non-rotating planet is designated as the closest-to-star point, then again, there may a latitude beyond which the ship could land.

Too much atmosphere would interfere with colonization, and planets might be excluded on this basis. Since smaller planets cannot long hold onto the atmospheres they have at formation, size is an indicator of this problem. The maximum size depends on the distance from the star, as it is easier to hold onto an atmosphere if the planet is far from the star and the atmosphere is very cold. Cold gases evaporate much more slowly.

Another question to be asked is the radiation level. If the star is a very active one, the colony ship would not even be able to come in close to it, unless some sort of shielding was build into the hull. Perhaps advanced engineering could figure out a way to get a mine dug, and alien colonists down into the mine without receiving too much radiation. Once under the surface, all the radiation is absorbed before reaching them. This is an interesting project to be considered.

With all these factors eliminating candidates, how much might be left? Our surveys of exo-planets are too limiting to calculate this number, but it might be that 90% are no good, meaning one in three stars, of middle class, has a candidate. There is more to being a mineral planet that simply being mineable with a surface not too lethal. There has to be the right mix of minerals.

An alien body has certain needs for elements, and alien technology has a different set of requirements for elements. Together they comprise the shopping list of elements, or rather minerals from which the needed minerals can be extracted. Some small molecules might also be extracted, principally water and carbon dioxide, maybe some others. The distribution of elements on a planet is a result of the original composition of the gas cloud, which comes from the effect of nearby supernovas in the cloud's history. Then there is the condensation question and the diffusion question, with minerals forming as elements and condensing into dust, and then being filtered by the solar wind and light output from the star over millions of years. After that, when the planet forms, geology plays a role in determining which minerals are at the surface.

The only planet we have any experience with is Earth, and it can provide us with a model problem. Suppose there was a planet in a state just like modern Earth but without any atmosphere, without any fossil fuels, no life, and of course no people, meaning no mining. Could an alien colony ship find the right minerals, in accessible form, so that it could produce a sustainable colony here? Perhaps U-235 is the key. We can mine uranium ore, refine it, enrich it, build a reactor, and extract more energy than was needed to construct the reactor and keep it fueled. Alien reactors should be even more efficient in the use of fissionable and fertile fuel than ours are, as we have had only a few decades of experience with fission power. Perhaps the guess of one solar system in three having a mineral planet is not too far from the truth.