Mankind Rescues the Earth!

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.

Geological Separation on Exo-Planets

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

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

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

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

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

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

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

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

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

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

Disease and Contagion in Alien Civilizations

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

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

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

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

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

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

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

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

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

Can Epidemics End an Alien Civilization?

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

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

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

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

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

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

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

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