Monday, August 31, 2015

Another View of Habitability

Astronomers use, or perhaps misuse, the term habitable to refer to a planet which in a near circular orbit inside the zone where water could exist as a liquid. There are many variations and perhaps each astronomer has his own preferred definition. The popular press takes these ideas and talks about new homes for mankind. Perhaps we should change the definition as well as the word.

Let’s generalize to cater to this blog’s penchant for talking about alien civilizations. Here is the proposal. Suppose you are in an alien civilization on some home planet. Your fellow citizens have never developed any colonies on other planets, but you are debating, or rather, thinking through just what you would all like to do. Your science is very far advanced, and you are aware that the planet, the solar system, and the galaxy all have some perils which might impact your home planet and put an end to your happy life there, perhaps even causing extinction of your species.

Let’s assume you don’t like that prospect. According to our classification of the memes which drive civilization, this means you are in category 0, 1a, 1b, or 2. So, which exo-planet gets the honor of being the first clone world. You want to clone your home world so that your species doesn’t go extinct.

It may be that you have already rendered your original species extinct, as you have used genetic engineering to make a better species. That’s the one you don’t want to go extinct. You don’t want to have it reduced to a primitive living level either. You want to maintain your standards of living for whichever of your citizens are alive at any time in the future. You live comfortably, and future generations should also.

Recall some details about your life. Because of the need to conserve materials and resources, you do a very high level of recycling, and that means that almost all of you live in almost closed, almost hermetic cities. You are living on fusion power, from a power station that is possibly located distantly from your city. You have robots and intellos all over your city, and have no problems with disruption from citizens or from the environment.

The debate rages on, and some citizen asks: “Do we need a habitable surface?” This question completely changes the debate. Would it be a big loss to live wholly underground? Having a surface is nice, but it is not necessary in the same degree as all of the infrastructure you have, the knowledge bank, the central control network, the sustenance activities, and so on. This opens up a large variety of possibilities that might have been ignored.

For planet-specific perils, such as basalt floods or strikes by unstoppable asteroids, living on another planet in the solar system provides the backup to ensure your civilization continues. There are solar system perils, such as rogue planets, stellar encounters, solar activity, solar flux changes, and probably more. These latter are not mitigated by having a local planet backup colony. However, compared to starting up an exoplanet colony, having a backup colony inside your own solar system is quick and cheap. It’s not very likely that two planets will occupy the habitable zone in your solar system, so you might have to make compromises. Going outward, towards cooler temperatures, allows you to use your own heat for your colony. If you are underground on some cooler planet, there would be insulation provided by the rock itself. For this type of local colony, requirements are far different. You would need to have the necessary resources on the planet to be able to sustain your civilization. This means, probably, nuclear fuel of the fusion variety, mineral resources of a wide variety accessible from one location, and not much else.

The key threat to your civilization’s deciding to go outward in their solar system is sustainability. The surface of your home world was great to evolve on, and fine to continue to occupy. Without the surface being habitable, in an origination of life sense, your civilization would never have gotten started. But you have already evolved to the peak you want to achieve, and any further changes in your own genetic structure will not be done by further evolution, but by using your knowledge of genetic engineering.

Surfaces were nice back in the primitive days when you had to get food there. But with genetic technology, food can be produced industrially, and after some centuries of doing that, you wouldn’t want to have to go back to the limitations and obstacles that grown food had. Food is superb, and available in as many varieties as several millennia of expert chefs can concoct. There is no demand for a surface that arises from the need to feed the population.

You are already recycling the air in your city. The city’s systems remove everything except the basic constituents and send the rest into the generic recycling bin. After a few millennia of dealing with leak problems, you don’t have any more of them. You have learned, over and over, what it takes to maintain a closed loop system. If you didn’t learn it at home, you learned it by building crewed planetary vessels.

The debate would conclude by deciding to have a backup colony on a local planet, provided that there was a suitable one. There are unremovable restrictions, such as gravity, but not many. Perhaps a large satellite would work as well as a planet. This decision has implications beyond the solar system you live in. Your choice for an exo-planet backup colony, or even a large population world, is not a world with a nice surface such as your home world, but one where there were resources. It may well be that energy resources are the critical deciding factor. If deuterium is your fuel, does the planet have it in a way that is accessible at a reasonable energy cost? If the atmosphere is methane instead of carbon dioxide, nitrogen or oxygen, can you accept it, and get your deuterium from the methane? An atmosphere full of it sounds like a sufficient quantity.

If we are looking around the galaxy for habitable worlds, we will have to remember that habitable in the sense of liquid water does not mean inhabited. There could well be large populations of aliens, established in a prosperous civilization, living under the surface of a world we do not classify as habitable. What it does have is deuterium, and that is the aliens’ definition of habitable.

Sunday, August 30, 2015

Starship Detection – Exhaust Recombination Lines

It would be nice to find a way to detect alien starships as they crossed the sky traveling from one solar system to another. If the galaxy is populated with alien civilizations, who travel between stars for one reason or another, we could prove their existence not only from them coming here to visit us or by intercepting a message from them, but by seeing them flying around the galaxy. We would not only prove their existence, but we would also prove that no insurmountable Great Filters prevent a determined civilization from traveling through the galaxy. As far as we know now, it might be possible and it might not. No data, no conclusion.

One idea was to see the results of nosecone heating from a fast ship, meaning a fraction of light speed, intercepting interstellar gas. Unfortunately, the only time this would be visible is if the ship was ramming through a Bok globule, where gas densities were much higher than the typical interstellar gas density. And they would likely avoid these globules, which don’t occupy a very large fraction of the occupied volume of the Milky Way.

Another idea is discussed here. If they used the most efficient type of propulsion, particle beams shot out at near light speed, they might have an effect. First of all, in designing a starship, you want to minimize fuel. To do that, you want to have exhaust velocity as high as possible, and that leads to near light speeds. The only way to get matter up to those speeds is to use something like an accelerator, and for them to work, you need charged particles. For this post, we won’t discuss the choice of heavy ions as particles, but just assume protons are used.

There’s a little problem if you just shoot protons out the back end of your starship. You develop a static charge which defeats the purpose of your propulsor. So you need two accelerators, one for protons and one for electrons. You shoot out equal numbers and stay electrically neutral. Protons love electrons, and will recombine with them along the beam path behind your ship. When that happens, hydrogen recombination lines are given off. These range from the ultraviolet down to the infrared. For the purpose of discussions, let’s assume they are all at the upper end of the spectrum.

What we want to do is to assume some large IR/optical/UV dish somewhere out in space, devoted to starship detection. In order to estimate its performance, you have to assume some things about the starship, namely, how big it is and how fast it is accelerating. The larger the ship, the larger the amount of photons is, proportionally. The faster the target speed, the larger the amount of photons, proportionally. The shorter the time to get from dead stop to target speed, the larger the number of photons, inverse proportionally.

What about the dish we just built? The larger the area, the more photons can be captured, proportionally. The longer the collection time, the more photons can be captured, proportionally. A simple calculation, assuming we were staring at the back end of the ship and getting a great view of the exhaust, is that probes, of perhaps 10 metric ton weight, accelerating to 0.01 c over the course of a year, would just be detectable at less than 0.01 light years, with a 100 square meter dish and an hour of detection time. A monster emigration ship, weighing in at 100,000 metric tons, which is a bit heavier than a large aircraft carrier, would be detectable out at nearly a light year. These are not large distances, compared to the size of the galaxy, perhaps a hundred thousand light years across. But they are something to start with. Suppose we ran the detection time up to 100 hours, assuming we solved the problem of the disk not being stable enough to hold its pointing direction. Now the monster ship is detectable at something less than 10 light years.

This is the best we might do with this equipment. It assumes favorable collection of the whole spectrum and more importantly, that the ship is pointed exactly away from the collection dish. If it is not going that direction, we have the problem of proper motion. All the photons don’t go into the same pixel. In order to accumulate say, 100 photons, which we assumed was a minimum for detection against a dark galactic background, there would have to be a mountainous amount of processing to pick all possible tracks and add up photons along it. With that, the proper motion problem might be solved if we had sufficient field of view. Something moving at up to 0.01 c out at a light year cuts across many resolution cells in an hour and proportionally more in 100 hours. Detecting something moving across the field is much more difficult, but perhaps not impossible with oodles of computing power.

Where the problem comes is, where do we point the dish? If we don’t have any information on when the ship left, where its origin and destination are, we are reduced to scanning the whole sky, which, with a dish this large, would take absolutely forever. Even if we were so smart that we could detect habitable planets near ourselves, we would still have the problem of knowing where on the line between them a ship might be. This reduces the amount of scanning tremendously if there are only two candidates nearby, but still it is a major problem.

What would be a great gift is if earth was near the line between two habitable planets. Then we would be likely to see a ship from the exhaust direction, and our chance of detecting it would be much simpler. Seeing it from the nose direction would be good too, unless we were really close to the line and the ship itself obscures the exhaust. Not too likely. This is the same consideration for tapping any interstellar X-band or other communication channel between a home planet and its colony. We need to be on the beamline. If we are really, really lucky, we are, but given the density of habitable planets, this is probably not going to be a lottery winner for Earth.

Saturday, August 29, 2015

Emigration Ships for Category Two Aliens

Category two aliens are those who do not like star travel, maybe it makes them seasick, and they refuse to do any until they absolutely have to, like when their planet is about to be destroyed or some such fate. They emigrate to some other really nice planet, where they set down roots and enjoy their pleasant lives, at least until that planet has a big problem.

There are two ways to do this emigration. One is to send some alien citizens there to get things going, and then reinforce them as much as necessary, by sending other starships after the first. This is what we called emigrant trains in a previous blog, where the possibility of detecting them was first raised. Nosecone heating doesn’t work, except if they fly through a Bok globule, which they shouldn’t.

Not all the aliens would emigrate, as the stellar problem or the planetary problem or the supernova problem or whatever it was that was going to ruin their planet for living there would all be predictable. They would have a neat way to emigrate, because they would have, as part of their development of asymptotic technology, developed long ago, have figured out how to do gestation of young aliens mechanically, rather than biologically. Actually, they could have developed good techniques for external gestation involving a combination of biological and physical tools. The point is that gestation of young aliens is decoupled from the presence of other aliens. They grow the next generation industrially, so to speak, rather than having whatever gender of aliens (if there was more than one, they might be hermaphrodites) used to give birth, lay eggs, bud, or whatever they used to do.

This decoupling means they just have to get the gestation machines over to the new colony, and turn them on. Of course, building the first city would be necessary, as well as exterminating the native flora and fauna if they didn’t want to adopt them. Starting a power plant and some mines to replace recycling losses would also be necessary, as well as developing a source of fuel for the power plant. Getting a spaceport set up is also clearly in the cards for them, unless they all plan to parachute down. In short, there is a lot to do there, but only a small fraction of the population needs to go. Obviously, they would have to develop a gigantic engineering plan, figuring out what to do first to minimize the amount of shipping from the old world they would need. But the main point is, that new aliens are all gestated on the new world, and the population gets gradually built up there. Back on the old planet, citizens live out the natural course of their lives, fifty years, a hundred years, five hundred years, or whatever. Emigration of the civilization is done without emigration of the population.

The second alternative is to do everything robotically, and only send a ship with some really spectacular artificial intelligence that could handle everything necessary to replicate the alien civilization on the new planet. The same idea of emigration of the civilization being unconnected with the emigration of the population holds.

How would the aliens decide between alternative one and alternative two? Flipping a coin is probably not the way super intelligent aliens, with master computing capability available at their fingertips, would do it. Likely they would do a cost-benefit analysis for emigration, which would be very different from a cost-benefit analysis for colonization. Category zero aliens are doing the latter, and category two’s are doing the former.

The cost benefit analysis would take into account the costs of the starships needed in the two alternatives, the time needed as compared to how much time they have before the basalt flood pops to the surface or whatever else what going to ruin the planet, how much of the home world resources would be required, and certainly other factors. Reliabiity would not be a factor, as they would build in backups, just as we do, so that reliability was high, and met whatever level of risk they were willing to take. It might just be that reliability, in the guise of taking care of unplanned events, is much higher with a ship with citizens on board, or it might be the other way around.

Suppose they chose alternative one, the emigration ship choice. What would an emigration ship look like? Here on Earth we have speculated a great deal about this, and there are interesting ideas in the areas of propulsion, power sources, artificial gravity, navigation, recycling, hotel requirements, hibernation if desired, shell hardness, and all the other things somebody building a starship would want to know about. There are even conferences on the subject.

Are any of these areas show-stoppers? In other words, is it impossible to design some component of the ship so that the requirements of carrying a crew over many light years can be met? One interesting area is artificial gravity. There have been some negative consequences found for humans living in zero gravity situations, and who knows, maybe aliens would also suffer from some. Or possibly, octopus people would not care one way or another. A civilization which lived underwater, if such things are possible, would just have to worry about not having any leaks. Mass requirements would be greatly different. Buoyancy reduces the effect of gravity and acceleration so much these octopus guys would hardly notice the launch. They would be looking for different worlds than land animal civilizations would, anyway.

For artificial gravity, a revolving wheel is the usual recommendation. Perhaps long-term revolving is bad for anything with a strong sense of gravitational direction, and then the question arises of how much awake time would be necessary if hibernation gets figured out for them. Since they are omniscient in the proper way, they would know if their species could handle living in a freezer for years. The other alternative is to keep propulsion going for a long part of the voyage, which provides some amount of gravity during both acceleration and deceleration. Using propulsion at a low level for the long term means that the average speed might be lower and the duration longer. Power requirements would be different as well.

It would be a foolish choice, and even we know this, to build the ship on their home planet. Building it as far out of the gravity well of the planet and its star saves on everything. The logistics of getting the components and supplies out to the distant construction orbit would have to be balanced against the difference in the costs of building the ship. The cost-benefit analysis of course includes all construction costs.

The first ship to arrive at the destination planet has to arrange the logistics of getting all necessary supplies and crew or passengers down to the surface of the planet. Perhaps the first ship would go into a planetary orbit around the star, and detach some smaller vessel to drop into planetary orbit, which would in turn have something smaller to land on the surface safely and securely. How large a load would have to be delivered?

The aliens’ cost benefit analysis cannot be done until they have determined what mass they need to put onto the new planet on their first trip there. This mass is determined by exactly how they plan to proceed. Materials which are not delivered must be mined on the planet. They can’t figure this out until they have determined the ease of access to minerals of various kinds.

Some alternatives are now apparent. Do they want to make a huge ship, capable of long endurance in orbit, with multiple third stage vessels going down to the surface with robotic mineral exploration probes, later to be followed by vessels with citizens? Or do they want to have the first ship just do exploration tasks, and drop citizens down from the second or later ships in the emigration train? It will be interesting to discuss some of these details later. If we can get an idea of which is better, lots of smaller ships or a few huge monster ships, it will make the job of detecting them easier. As noted in another blog, if the galaxy has as many populated planets as some calculations indicate, there will be emigration trains running in the galaxy much of the time, provided there are destination planets available.

Friday, August 28, 2015

A Toast to Fossil Fuel Companies


Text of Speech by Governor Xplank Flzit, Mat. 32, 21309

First I would like to thank the Board of Controllers and their President, Zpluuu Brgrt, for inviting me to this excellent dinner. The President and I go back a long way, three or four hundred years, and I have always appreciated his advice and wisdom, as well as his excellent choices for menus. (Pause for applause)

Zpluuu asked me to comment on a subject of current interest to the Board and their guests today, but I decided to go in another direction. Instead, I am going to recall ancient history and see if we can learn from our ancestors. You all know that we are living in a time of plenty, that our needs are more than satisfied and our wants are more than cared for. (Pause and gesture toward President Brgrt)

It was not always that way. Many millennia ago, we lived in a time where there was scarcity and hunger and citizens lived on the edge of survival. Food was not plentiful, the non-urban areas on our planet were not all natural parks, individuals struggled with the allocation of what goods there were, with many running short of such basics as clean water and clear atmosphere. We emerged from that deplorable situation because of some actions taken by a few individuals that are almost forgotten now. Yet those actions can serve as inspiration for us nowadays. We do not face the tremendous threats that the early citizens did, but each of us has decisions to make in our lives, and remembering how these individuals showed tremendous insight to find the right decisions and courage to make them can give us the pluck to take the right actions.

You may be asking, how can making the right decision take courage at all. Just do it. Well, back then it was not clear to the masses of citizens that these decisions were the right ones, and these exemplary individuals had to forego popular acclaim and acceptance and plunge ahead with what they saw as the right course. As we all know, the decisions made in the past led to our current joyful world, but the point I am making is that it was very far from clear that these decisions were the right one. Yet they were made – this is the courage that I referred to.

I can just walk over to the energy tap on the wall there (point at tap) and withdraw as much energy as I want. No one has to think about energy except for a few of us. Deuterium is extracted from the sea, sent to the power stations, where it is converted to almost unlimited energy. That energy makes our life of plentitude possible. But in the era I am referring to, there was no fusion. Someone had to provide the energy for life then and for the long period of research and development needed to establish fusion. The individuals I am commemorating are the ones who provided the energy bridge that solved this problem. They did not make one decision to provide it, but instead made daily decisions on how to extract combustibles from the crust and transform them into usable energy sources. They would spend their entire lives doing this. Can you imagine a life where citizens actually had to work every day? This was their life and they did it with flair, solving problem after problem in the early energy areas. We live in the world they made possible, and I want everyone in the room to toast them. (Wave hand downward) But not yet. There is something else they did that is equally worthy.

When you go outside now, you expect to have a beautiful day, and precipitation in the night. Gentle breezes are usually blowing, adding to our enjoyment. But in the era I was talking about, this was not the case. Instead, the atmosphere was totally uncontrolled, and it not only ruined excursions, it did damage to things and even occasionally killed citizens. Hard to imagine? Yes, but I am telling you what really existed. Not only was the atmosphere uncontrolled, it was unpredictable. Citizens did not know what was going to happen, and even did not know when dangers would arise. It sounds like the government was a total failure in this regard, doesn’t it. (Look around room)

But the government couldn’t do anything about it. Citizens at that time did not even dream that things could be any different. They were born in these conditions, and lived their short lives with them. But the same people who built the energy bridge did the first experiment that changed our perspective on the atmosphere. They changed the temperature of the planet by adding gases to the atmosphere. It took a little while for this to be appreciated, but gradually the citizens understood that the atmosphere was theirs to adjust and to modify. That was the beginning of the end to scarcity. It took bold actions, even unpopular actions, but these individuals summoned up their courage, and did them.

You may not have ever heard of the words, “Ice Age”, unless you have studied paleontology. Any paleontologists here? (Look for hands raised) That was a time when there were glaciers, huge mountains of ice, on our planet. The same people who solved the energy bridge problem managed to eliminate them, which was the next step in bringing the atmosphere under control. I see some faces here indicating disbelief. If you want something to disbelieve, think about this. At one time, the entire planet was covered with ice. There is no chance of that ever happening again, and for this benefit and all the others, unlimited power, beautiful days always, calm breezes and so on, let’s now raise our glasses and toast the ancestors who made this all possible. Cheers! (Move raised glass from one side to other, then sip during applause)

Thursday, August 27, 2015

Never Trust a Historian to Predict the Future

George Santayana, the Spanish-born and American-educated naturalist philosopher, had a aphorism that has been quoted to death: “Those who do not remember the past are condemned to repeat it.” This quote is a criticism of people who fail to use history to understand the present and unavoidably fall into the same pitfalls as others have before them. It is based on the observation that people have not changed over the last few centuries, as regards their veracity, ambition, greed, and tactics, so not learning about the history of recent events sets up someone to be victimized as others were. P.T. Barnum had a saying with a similar core: “There’s a sucker born every minute.” Santayana was alluding to political leaders and other important social figures, while Barnum was talking about ordinary people. However, the point is the same. Gullible people abound at all levels.

Santayana was quite right in that ignoring history can, in some instances, lead to a pitfall. But the quote is overused and overemphasized. Emphasizing historical knowledge as a way to predict the future is not a good idea. The future is not the past.

Historians, or pseudo-historians, rather anyone who studies history, reads books about history, writes about history, thinks about history, and dreams about history is going to predict the future using what they know and love: history. Ask a historian what will happen in the future and the only option they have is to cleverly think through the past, the part they know, and find analogies and pick the closest one. More clever ones may combine two or more. Historians are endemically incapable of predicting novelty or something which has not happened before. They have learned how to understand the past, and they are bound to use that understanding to analyze the present and figure out which past event is going to recur, albeit with different faces, different times, different locales, and so on, but basically the same framework and sequence of events.

Many historians are quite eloquent and are able to express themselves very competently and are able to make arguments as to why their particular historical analogy is appropriate to the present and how the future will therefore unfold. Historians are no different than anyone else predicting the future in that they lace their commentary with caveats, and give themselves slack especially in questions of timing and duration, but they suffer from a much greater and deeper failing. History is their only card.

If something has features in it which make it different from anything in the past, then historians have the option of belittling it, downplaying it, ignoring it, or pretending that this novelty is just like a past novelty so the history of how the former novelty played out should be used to predict how the new novelty will unfold. They cannot see something completely new, or with completely new aspects. They look one way, backwards, and while their guessing may be right on in some instances, novelty is their kryptonite. They melt.

There is another type of historians who are not often so eloquent, but more numerate. These are the trend followers. Their idea is that whatever happens in the future is a project of what is going on now. They don’t use so much of the past as a historian, but they use a slice of the past to compute or otherwise deduce what trends are going on, and then project them. In numerate situations, straight-line projections are often used. Noise in the data is filtered out. This type of prediction is very useful if nothing is happening that would change a trend, but unfortunately it almost always is. We live in a changing world, and one that is tightly interwoven, so one thing changing makes another thing change. This is especially true in situations where people are making decisions, as a decision can be made in a split second, and then the trend line snaps.

Often, trend predictors are mathematically sophisticated, so they invent a model which captures how they believe a number of variables are interacting, and take some data to get correlations or other relationships between them. Sometimes the model is emphasized and sometimes the data. Always the number of features incorporated is limited, and often the data is not robust enough to establish the details of the relationships between variables, so it is hypothesized, and the hypothetical nature sometimes is underemphasized. The flaws in such an approach in a situation where external, unincorporated variables are undergoing significant change should be obvious. Modeling is a tool for exploring consequences, not a predictive method.

So, if the past cannot be used to predict the future when things are new, and the present cannot be used to predict the future when change is occurring, what is left? In our area of interest, alien civilizations, trying to find some past Earth situation to analogize is prima facie inappropriate. Projecting our rate of changes is going to fall far short. Nothing is left to predict what alien civilization will look like and what activities they might take, except three things.

One is normative thinking. This is looking at a situation and asking what physical, chemical, mathematical and other laws must govern it, and then what implications there are from these conditions and limitations. When talking about aliens, sometimes someone will say that, for example, the laws of physics will be overturned by alien scientists and so they will be able to do anything. The history of physics doesn’t indicate this, but we can simply go forward with the assumption that magical events, ones which do not follow the science we know, are not going to be considered.

The second one is to find uncoupling by time and length scales. Things which happen in seconds don’t interact well with things that happen in years. Averaging happens in the quick to long direction, and constancy happens in the long to quick direction. There are a number of time scales and length scales which are important to thinking about star travel and evolution and other key phenomena, and if uncoupling dominates some relationship, they can be thought of independently.

The third thing is parameterization. If we can’t figure out some variable, we can break up the range of possibilities into a few classes and look at each one independently. Usually results are not sensitive to the exact value of a variable, so a few classes are enough to generate insights about the situation where the parameter plays a role. Obviously this cannot be done with many variables simultaneously, so the insights discovered by exploring one parameter have to be used to decide on a most likely value. Then this tentative case can be explored more deeply.

I don’t want to imply that history is not a fascinating subject, it is. I don’t want to imply that modeling is not a challenging and important skill, it is. I do want to imply that these tools may not be very useful in understanding the answer to the blog’s original question: “Where are all the aliens?”

Wednesday, August 26, 2015

What is Expected of a Colony Planet?

There are two reasons for probing the question in the title. One is that some of the categories of alien civilization, zero, the ones, and two, will create colonies on other habitable planets, and they do this with some intention in mind. This creates some expectations for the colony planet, and establishes something like a relationship between the two. Understanding this may help us understand alien thinking, and perhaps the foundational question of this blog: Where are all those aliens?

The second reason is that, just maybe, we are a colony of another planet. Instead of congratulating ourselves over and over about rising up from primordial slime and shooting for the stars, maybe it is the case that we didn’t really do that. Somebody came by and gave us a jump-start to get over a Great Filter, which had stopped us cold. If that is the case, perhaps we owe something to the founders. Perhaps we owe them nothing. Perhaps they don’t even exist anymore, making gratitude rather moot.

Recall with a sweet spot planet, the time for colonization to be wrapped up is simply the travel time between the origin star and the destination star, plus a millennium or a few millennia for some modifications of the planet, plus some time to establish the colony, which might be a millennia to have the first small city done. The colonists certainly have good records of what was done by the origin planet citizens in order to make over their planet and start it off in the direction of becoming a full-fledged inhabited colony world. They obtained their knowledge, their supplies, and their seeds from the origin planet. Their memes are derived from the origin planet. If distances were not too far, there could even be slow communication between the origin planet and the destination planet. They set out with the same goals as the origin planet had for sending them out. They were to clone the home world. This is the goal that alien civilizations of category 0 and 1a would have, as a result of the memes which are the foundation elements of their policies.

Planets in the penumbra, those which are not sweet spot worlds, but which can be modified to become one, given a more substantial amount of geo-engineering, would fall under the same expectations. Times for colonization would be considerably longer, but once done, there would be no reason to modify the design for the civilization that will reside on it. Home world is the paradigm, to the extent possible. It is not to be copied, city for city, but the basic principles that governed the design of cities, other infrastructure, exterior areas, and the biome would be the same.

Alien civilizations of category 0 and 1a differ in the desire of the population, as expressed in the memes, to maintain the same genetic plan on the colony as on the home planet. Category 1a is willing to accept habitation on planets further out in the penumbra than category 0, as they make modifications genetically to inhabit the new planet.

The originating planet would expect the colony to copy the home world, and not to fall victim to any peril that might affect a colony. Undoubtedly there are some perils that are germane especially to colonies, and these are worth exploring in this blog. But the expectations of the home world for these categories is to copy and clone the home world; the colonists would expect to do the same.

The story is completely different with category 1b. The meme, or guiding rules, of the alien civilization sound almost minor, but the elaboration of it toward a grand strategy for colonization leads to a complete difference. Category 1b believes that life is a treasure, and they want to spread it to other planets, for various reasons, such as to preserve life. The former two categories believe more in intelligent life, and for category 0, their own genetic form of intelligent life. In other words, category 1b draws the circle of what is valued around much more than 1a or 0. The aliens of category 1b fully understand that only a star traveling civilization can spread life, and understand that in order to perform their self-chosen mission, they may have to have clone worlds which will have the same mission. Thus, they would have a dual mission, on sweet spot worlds, and maybe for a distance into the penumbra worlds, set up colony worlds which would partner with them in preserving life in the galaxy and even in the universe.

Aside from creating partner worlds, for the purpose of preserving life, Category 1b seeks to seed planets that do not have life, and to bypass Great Filters for planets which do have some limited life. Their persepective is of the time scale of the galaxy. Seeding a planet accomplishes nothing in a short scale, and perhaps little over a million years. Over a hundred million years, the planet may develop the beginnings of life. The alien civilization of category 1b may understand that their civilization may not last long enough to see the next stage of their seeding trials, but using the knowledge they have of the relevant areas of science, they can predict the probability of success, and also determine how best to perform the seeding.

Category 1b does not restrict itself to the penumbra worlds, but would choose to seed life wherever it can grow and prosper. The observational results of having a galaxy with category 1b civilizations would be quite different than one with the other categories. Worlds where there should be no life may have it. Biosignatures on planets which would not by themselves originate life would have it as a result of seeding by a category 1b. In this blog, we refer to worlds which can originate life as solo worlds. To the extent that we can determine which worlds are solo worlds, as opposed to which worlds have life on them, we can surmise if there are or were an alien civilization of category 1b taking deliberate actions to spread life.

Category 1b home world clones would have the same expectations laid on them as the former two categories, namely, get your world developed ASAP. But category 1b has a further requirement: start helping us with the Grand Life Propagation Project. For seeded worlds, there is little expectation that anything would happen fast enough for there to be any relevant expectations. The home world would expect to see success of their seeding program, but only via their own observations would they know this. They might hope and expect that seeded worlds will develop the same meme as themselves, as they would know their own pathway to the meme.

Incidentally, category 1b civilizations would have a consequence of their chosen star travel meme and that would be to continue their civilization for as long as possible, but long meaning long in galaxy time, not planetary time. Whether that is possible or not remains to be explored.

Alien civilizations of category 2 are similar in actions to those of category 0, and differ only in quantity of colonies. Category 2 wants to continue having a home world, and when theirs is threatened by some peril, they need to emigrate, gradually, to a sweet spot planet with close to the attributes of their own. Then they stop traveling though interstellar space.

What we don’t have a handle on is the likelihood of the different categories emerging in the earliest days of the Milky Way galaxy. Nor do we understand yet if Great Filters will operate, and to what extent. In more detail, there will be solo worlds elsewhere in the Milky Way, unless some Great Filter has eliminated all of them except us. These solo worlds can move through the evolutionary sequence, and perhaps become plateau planets of some level. Those which pass through all the hurdles to become star-travel-capable will have made some choices as to what they will do relative to the exo-planets both near and far, and this choice is referred to in this blog as their meme component relative to space travel. If the first civilization to emerge from the evolutionary and developmental sequence of stages is a civilization of category 1b, they will start seeding the planets and even satellites as much as they can afford to do. If it is of category 0 or 1a, they will start populating planets with intelligent life. Category 2 just moves their home around.

It should be clear to all readers that we are not a colony of a category 0, 1a, or 2 alien civilization. It should also be clear that we may be a colony of an alien civilization of category 1b. It is therefore incumbent on us to try and figure out if there would be any, by exploring more details of how alien civilizations would develop their memes on the way to asymptotic technology and star travel. We could be on a solo planet, but if we are a category 1b colony, or rather a seeding experiment, this would imply two things. One is that category 1b has memes that made sense to a civilization far more advanced and thoughtful than we are, and perhaps we should think about adopting them. The second is that we have a mission.

Tuesday, August 25, 2015

Could Aliens Still Be Like Earthlings?

Many, many science fiction writers like to portray aliens as being like Earthlings, but with more technology. To be specific, they think about military technology, or starship technology, not any of the other many types of technology. Then the inevitable conflict between them and us can be portrayed. This is a common way to write dramatically, but does not make much sense.

Technology does not go forward in one direction only. We do not grow smarter only in how to build weapons. It can certainly be that we have found the technology to build weapons easier than the technology to develop political systems that satisfy everyone, or the technology to educate people in the many ways they need to eliminate personal and social problems, or the technology to cure genetic problems, or the technology to provide ‘power to cheap to meter’. We have not found the neurological technology to cure individual pathologies that cause social disruption. And so on.

This does not mean that we will not solve them, nor does it mean that any alien civilization which continues to advance in technology will not find them. Technology is like streams of water flowing down a glass window. As the rain continues, one stream may flow faster than another, but the other will flow also. There is no bar toward figuring out economics, but it might be harder than figuring out high-power lasers because of the difficulty of clearly defining the terms and deducing relationships. Hard does not mean impossible, it just means later. It also depends on the funding. Huge amounts of funds spent on weaponry have produced some impressive capabilities in weaponry. Less amounts of funds spent on neurology have produced less impressive capabilities on curing individual ills. But science is cumulative. When something gets discovered or invented, it stays discovered or invented. When an observation is made, the results are typically preserved if it provides useful insights, and often observations are repeated, in a different or improved way, and the results are verified or adapted to the new observations. Science just keeps building, and not only in the hard sciences, but also in those sciences that are really hard, in the sense of being harder to do.

We are looking to understand alien civilizations that have gotten to star travel, not sending one probe out on a one-way mission with almost no communication capability and a speed that is nowhere near a good fraction of light speed, like 10%. Going from where we are now, barely capable of sending probes to other planets, to sending starships out to another star system, will take us or an alien civilization time. I use millennia as a guide. Maybe one millennia of science is all it takes to get to asymptotic technology. But just think of a thousand years of doing science, not only in weapons and planetary probes, but in all the other areas, like political science, education, neurology, genetics, economics, governance, robotics, and fifty others. Suppose another thousand years of learning how to educate people, how to solve any personal disorders, how to remove genetic dispositions to self-harm or social disruption, how to increase everyone’s intelligence, and others branches of learning all happened and what would we have?

After all this learning and adaptation of learning, would we expect to see aliens blowing each other up, squabbling about allocations of resources, mis-communicating intentions, governing with tyranny, or doing any of the other things which lead to various unpleasantnesses today? It is almost unimaginable that progress in these areas would not result in problems like this being solved. And thus, when we think about aliens who have mastered that millennium of technology, and then for good measure, spent another few millennia tweaking it or completing the little details of it, they have left the problems we see today so far behind them that they may not even remember well what they were like.

This is after a few millennia. The age of the universe is measured in billions of years. Let’s think about a compromise, an alien civilization which is fairly new, only having existed for a few million years. That is a brief blip in the age of the universe. Yet they have there a thousand times more experience in solving problems and dealing with everything under the sun. If we expect, judging from the rate at which we are advancing technology, that everything will be completed in a thousand years at most, what possibly could remain undone after some millions? Is it anything like reasonable or even conceivable that an alien civilization would not work out all problems in that length of time? No. So when science fiction authors write about aliens as if they were humans in crab bodies or whatever amuses them, they are ignoring the fundamental time scales of the universe as compared to social development and technology advancement.

It is certainly possible to dispute that an alien civilization could last a million years, and it is one point of discussion in this blog as to why they might not be able to. There are many aspects to this amount of endurance, and perhaps they can all be discussed one by one. But if it is indeed possible, how could they not have developed solutions to every social ill that could ever occur?

Some far-fetched concepts are possible. Maybe the very successful aliens live a million years and establish an outpost on some planet, and then they all die out. Why? No reason, they just do. They leave behind all the manuals to their weaponry technology in easy to translate form, and some very new civilization happens upon it before they have solved their social problems. The new guys are still battling one another, and the group that gets the technology uses it, becomes the dominant power among their factions, and then decides to take over the galaxy. Then they come to invade Earth.

It is not impossible to concoct very improbable scenarios, probably with many loose ends that unravel upon examination, for some of the alien visions that science fiction has dreamed up. If the whole point is to create some dramatic situation, then so be it. If the point is to use science fiction to assist us in conceptualizing what an alien encounter might be like, then this is not the path to take. The path to take is to understand the flow of technology, meaning both science and engineering, and the timescales involved, and use that to create a scenario which can then be explored in detail. It is a question of entertainment versus a more visionary task.

One aspect of technology development is, as noted, it occurs in different rates in different areas. A possibility is that a new alien civilization develops in some technology areas, but for some reason, the other areas go very slowly. Then they might have some basic star travel before they learn how to calm their society, educate their citizens, and do the other tasks that will come. So, for a short period of time, we might have gunslinger aliens. The probability of encountering them for the few millennia it takes other areas of technology to catch up, instead of for the million years after it does, is very small. Perhaps scenarios in which these delays are exacerbated should be explored. A catalog of the ways in which an alien civilization could wind up exploring its local neighborhood of stars while still not completely at asymptotic technology might be an interesting exercise. So far, it seems the probability of these is very small.

Monday, August 24, 2015

Recycling in Alien Civilizations

No alien civilization can endure for millennia or especially a million years without extremely effective recycling. In the early days of a civilization, when it is in the process of developing technology, resources may be abundant, and there does not have to be even a thought of recycling, It starts to become a mandatory choice when the costs of finding new sources of materials exceeds the costs of recycling. This would happen at different times for different materials.

One part of recycling that develops in primitive cultures involves the food chain. The basics of food chain recycling are the same as with any other materials. Energy comes in and transforms non-useful materials into useful ones, composed of the elements or molecules involved with nutrition for the type of alien that comprises the civilization. The primitive culture can learn to recycle wastes from photosynthetic organisms and consumers of them into materials for the photosynthetic organisms to grow with. On Earth, that was mulch and manure being used as fertilizer.

Another part of recycling also develops in primitive cultures. A tool which has a broken part is disassembled and rebuild with a new piece replacing the broken part. Energy is used to rebuilt the tool. On Earth, an example might be a stone age culture with axes. An ax handle breaks and is replaced.

A third part of recycling arises in slightly more advanced cultures. A metal-using culture would learn to refashion metals of certain kinds. On Earth, perhaps the first was gold. A piece of gold jewelry that was unwanted could be melted down to make some new piece.

The fourth part of recycling comes at a bit more advanced point. Biological parts are replaced, and an early example is the grafting of trees, where a rootstock is used from a hardy survivor variety and is coupled with a branch of a more prolific or more useful variety.

Thinking through these aspects of recycling on a society-wide basis shows that recycling becomes more and more prevalent as the society progresses, both from the ability to recycle which is generated by the advance of technology and also from the need to recycle, which comes from the scarcity of some resources. The same divisions hold as society advances. There are two arenas, the biological and the mechanical, and two methods, parts replacement and materials reuse. These four divisions become somewhat entwined, but serve as a clear set of definitions nonetheless.

One could even say that recycling began with chemotrophs, with chemoheterotrophs recycling chemoautotrophs by eating them. The organic materials that were part of the organisms that directly fed on the chemical energy present in the environment were recycled into other organisms that were incapable of absorbing the chemical energy themselves, but could digest in some way the organic structure of those that could. So recycling can be said to have predated civilization by a billion years or two.

The ability of an alien civilization to survive on a single planet is governed by its ability to maintain a resource flow that sustains it. For all the basic materials that are being recycled in an alien city, there is a nominal loss rate. Some energy expense is needed to replenish these losses. This is independent of the energy flows within the city. This exterior energy flow is needed to locate the resources, to mine them or otherwise extract them, and to process them to the point of purity where they can be introduced into the city to replace the losses there. The energy needs to be obtained, ultimately, from the basis energy source of the alien civilization, which is likely to be fusion.

An important question for understanding the long-term survival of an alien civilization is what is the energy consumption for resource introduction, as compared to that for the sustenance of the city. In other words, if you looked at the energy being used in the alien civilization, what fraction is being used to obtain materials to replace losses, and what is used for the city and other miscellaneous uses in the city, such as transportation between cities? When the resource introduction fraction of energy use becomes large compared to the rest, which is used to maintain the living standards of the population, the civilization is approaching scarcity.

This approach to understanding the possible longevity of an alien civilization is done material by material. One could ask how much energy, as far as it can be divided, is needed for each material. Sometimes, several materials are obtained conjointly, so the calculations may be a bit messy. Even so, the basic idea of looking at individual materials in recycling and replacement shows something new. As the society ages, the differential costs of different materials changes, and so, instead of the city being essentially unchanged over the course of millennia, economics would indicate that some substitution of materials would be necessary. Which materials depends on two factors: the irremovable losses of individual materials and the energy cost of replacing them.

Besides uncovering this source of gradual change within alien cities, another becomes apparent. As some materials become relatively more scarce and more expensive, measured in energy required to replace them, the details of recycling might change. This would be a subtle change for citizens, and possibly a very slow one, but it would be a change. So, in order to endure for many millennia, recycling patterns and usage patterns would shift to maintain the most economic usage.

With the knowledge of how much resources existed on their planet, these changes could be anticipated, and long before there was any exorbitant increase in energy costs to replace some material, it could be substituted out for a more common one. If ocean extraction is used for some materials, land mining could be replaced with ocean extraction as the costs became favorable for this.

If the alien civilization lives in a solar system where there are resource supplies on other planets, the civilization could arrange for certain supplies to be retrieved from other planets, provided the costs were reasonable. Thus, the changes in the alien society forced by resource limitations might also lead it to become more interplanetary in its activities. Again, this would be a slow change, but it is a more profound change that simply switching from mining to ocean extraction.

It was not entirely correct to say that alien civilizations could last for many millennia or millions of yeas without changes. If economics, actually energy consumption, is used to determine social behavior and the arrangements in the city, there would be some changes resulting form material losses. These changes do not seem to be substantial enough to cause major social change, but it will be worth exploring in the future.

Sunday, August 23, 2015

Survival Memes in Alien Civilizations

Several posts have talked about the memes than an alien civilization might have regarding star travel [here, here, here, here, here]. These star travel memes are only one component of the whole complex of memes that the civilization must have to define how individuals behave and how the society as a whole makes decisions. Another meme closely related to the star travel meme is the survival meme, and in fact, they overlap.

Category 0 alien civilizations are characterized by a desire to colonize other planets by planting colonists from their planet on them, and establishing a clone of their home world there. There is no doubt that these civilizations highly respect their own civilization and their own citizens, and regard them so highly they want to produce more of them. Their survival meme is as strong as it can be. They might be called the predators of the galaxy, but they do not seek to eliminate other civilizations as a goal. Instead, other civilizations are simply impediments to their propagation of themselves, like a lack of resources or an unpleasant climate on a planet.

The survival meme also impacts other decisions beyond that of colonization and star travel. On their home planet, and on each successful colony world, they would have to decide how to preserve themselves for the long term. They would be the most aggressive in taming climate change, for example, seeking to control the climate of the world and preventing such things as ice ages by tampering with the atmosphere. When a problem occurs on their home world or on one of its clones, they do not have the option of emigrating to another planet. They are already doing that, but not for emigration, for colonization. This means that they would seek to survive on their planets for the longest possible duration, or on other planets in their solar system.

Some of the implications of that decision should be discussed, and will be. One relates to population size, and the tradeoff between resource consumption, minimized as much as possible by extensive recycling, and the total number of citizens. This tradeoff is actually tripartite, as it also relates to the living standards the civilization chooses for itself. Of course they would be optimized, so that a given choice of living standards would be done with the minimal use of energy and resources, but once that optimization is done, the stark realities of the tradeoff between population, resource consumption and energy consumption, and living standards stand totally exposed.

Category 1a civilizations seek to clone their culture, independently of their physical form, onto other planets. The difference between a category 1a colonized world and a category 0 colonized world is not in technology, it would be the same, but in the form of the population. Category 1a would be happy to modify their own form to adapt to a different planet or to genetically create something that was optimal to another world. This means they are somewhat more open to a choice of planets for colonies. Whether that implies they might leave a planet with a wholly robotic civilization needs to be discussed further.

The survival meme for an alien civilization of category 1a is not as strong as for category 0. They do not necessarily seek to maintain their existence on their origin world, as long as their advanced culture has already been spread to other planets. They have not the slightest interest in voluntarily casting themselves into extinction, but may not make any extreme sacrifices to carry on surviving on the home world. Their view is of the whole galaxy, and if one planet becomes uninhabitable, even their own, that is sad but the galaxy wide civilization is not greatly affected, any more than losing one city on a world with a great many would be.

Category 1b civilizations are not so in love with their own civilization, but with the existence of biological life. Their colonies are plateau planets which have failed to develop, and which they can make some changes to so that life will continue to prosper. They are diametrically opposed to colonization of the type that category 0 proposes, in regard to worlds where life has gotten started, or could have gotten started. Their perspective is extremely long, as evolution on a planet occurs over billions of years, unless accelerated by seeding. Their attitude toward survival is not as tightly connected to their star travel meme as categories 0 and 1a. They could have the very strongest meme for survival, and if their home world went into jeopardy, they would face a conflict between their desire to allow life to flower by itself, perhaps with some assistance, and the need to take over a whole planet to replace their home planet. How that conflict works out is not dictated by the details of their choice of category 1b for star travel.

If the first civilization in some neighborhood of the galaxy developed a category 1b civilization, how would it react to the emergence of a category 0 on some planet near them? Would they regard it as a form of life and do nothing while it colonized worlds, perhaps some that the category 1b civilization had seeded long before? Would they seek to intervene with it before it did any colonization, and how would the intervention go? Would it be solely restricted to trying to change the star travel meme of the category 0 civilization or would stronger measures be employed?

A category 2 civilization is simply concerned with having a home planet. They do not want to colonize the galaxy, but simply to have somewhere to move if their planet is threatened, as all planets are, sooner or later. Do they survey the surroundings and attempt to do something to plan for this event, and somehow stake a claim to their backup planet or planets? They have a strong survival instinct, and would likely take whatever actions are needed to ensure that they have somewhere to go. Just how an alien civilization would prepare for a migration at some distant time in the future is an interesting question, as is what lengths they might go to so that the planet they regard as their lifeline does not develop in a way that would interfere with their plans.

A category 3 civilization does not travel the stars, because of a voluntary decision. They can have less of a strong instinct for survival as a category 2 and may make plans for their own demise, as a civilization, in a comfortable way. Any alien civilization past asymptotic technology is in control of its own population count, as gestation is something under technological control. Extinction merely means turning off the gestation machines. And category 4 is not really a star-traveling civilization, nor even one which has any instinct for survival, at least long term. The idea of having a colony planet around a different star would seem weird to them, as they have no meme for doing such things, nor do they place much value on technology or on life itself. How can a civilization develop such a meme? The answer is not that they develop such a meme, but that they lose the memes they might have had before. Category 4 is the end result of a civilization which, for some reason, has a societal failure of some kind, and loses the meme it once had, perhaps gradually allowing it to be forgotten. Any other category of alien civilization can suffer meme decay, and wind up as a category 4. How this might happen deserves to be discussed separately.

The mix of beliefs that an advanced alien civilization has, in regard to star travel, is closely intertwined with what they wind up valuing about themselves. Understanding how they get to that point is a subject that determines what we might find in the galaxy, should we ever gain the capability of detecting the signatures of other civilizations.

Saturday, August 22, 2015

Would Aliens Engineer Whole Planets?

Let’s talk about the time scales of colonization. If the aliens who are looking around for a planet to start a clone of their own world, like category zero and category 1a do, with some important differences, they are seeking an almost habitable planet, a sweet spot planet in this blog’s parlance. It is like an empty house in good condition. You just move in. There is some difficulty about there being air to breathe, and we assume that aliens who move to the stellar traveler level breathe oxygen. Alternatives to that assumption will be discussed separately. Everybody knows that Earth wasn’t born with an oxygen atmosphere, the chemotrophs evolved a version of chlorophyll that produced it, and then it took about a hundred million years to change the atmosphere.

That’s too long to wait. One solution for the aliens is to look for a planet which has made the chlorophyll oxygen transition, and take it over, provided other conditions are right. Category zero sees this as a gift to them, and they proceed immediately. Category 1a sees it as a gift only if no intelligent life form is already there, and they proceed immediately on those which have none. Category zero would like gravity to be close to that of the home world, but category 1a would not mind modifying their stockiness to cope with a somewhat wider range.

The other solution is to add oxygen. Obviously this is not something that can be brought along in the hold of the starship, but it is an interesting question as to how fast an advanced alien civilization could transform a no-oxygen world to an oxygen world. Suppose they seeded the oceans with a life-form designed for fast growth and to be as efficient at producing oxygen as possible, given that this planet would have no ozone layer protecting the near surface waters from harsh UV, if the sun made a lot of it. Assume the atmosphere has abundant nitrogen, as early Earth had, and the rocks have enough available minerals to support a fast growth.

The atmosphere has about 4 * 10^9 million tons of oxygen. The mass of life on earth is roughly 4 * 10^6 million tons. If each organism produced its own weight of oxygen in a year, this divides out to a thousand years, give or take an order of magnitude. If these numbers relate to early Earth, the obvious question is why did it take so long on Earth to change the atmosphere? Was there a shortage of magnesium in the oceans, limiting the number of molecules of chlorophyll that could form?

If the target world was short of dissolved magnesium could the aliens find enough and increase it sufficiently to meet their thousand year target? There may be a different explanation, as magnesium is a very common element, and is the third most common element in our ocean water. Perhaps that is the result of all the sea life that used it?

The aliens might set a target as 100 thousand million metric tons of biomass, and if chlorophyll molecules occupy 1% of the total, one thousand million tons of just that molecule is needed. The molecular weight of magnesium is about 24 and chlorophyll about 930, so we have about 25 million tons of magnesium. About a million tons of magnesium is mined each year by us on Earth, where we don’t use much of it, so 25 times that is not a big deal. Thus, aliens could probably, over a thousand years, dump enough magnesium into the ocean to replace a shortage.

The conclusion from this hodge-podge of numbers is that aliens transforming a planet’s atmosphere appears feasible, given a millennium time scale. If they had been a civilization for many millennia, or even for millions of years, this is a reasonable project.

Gravity is obviously not something that can be engineered, but what about climate? Average temperature is controlled by the orbital radius of the planet and the output of the star, but it is also affected, mostly in the upwards direction, by greenhouse gases. If the original world was too cold, could the aliens add enough of a greenhouse gas to raise the temperature to something more to their liking? As discussed earlier, the answer is yes, they could banish an ice age. This is in accord with their ability to change the oxygen content of the atmosphere itself. The amount of greenhouse gas needed for a significant shift of temperature is not likely to be as large as the oxygen content, so if there exist biological methods of producing the greenhouse gas, it is likely that the engineering of the temperature could also be done.

What about wind speed? If there are prevailing high winds on the planet, would there be any way in which these could be reduced to a level commensurate with living there? Winds are generated and controlled by the differences in heating of the atmosphere that goes on in different parts of the planet. The differences in heating come from axial tilt, which is not something that might be affected, like gravity is not. However, if the difference in heating came from the difference in albedo, with the polar region being covered with snow and ice, making a climate change with greenhouse gas might mitigate the winds. Melting the ice might also allow large oceans, if they existed on the planet, to begin to flow warm tropical water into the polar regions, again reducing the heating difference. So, winds might be incidentally reduced.

Another aspect of a planet’s favorability is the length of day. Aliens would probably like a day around as long as their own was, but changing the spin rate of a planet is difficult to conceive of. The spin rate of Earth has been changed significantly by its interaction with the moon, but this option again seems beyond the pale for alien engineering.

So, the sweet spot world search includes gravity within a range, temperature tolerable or on the cold side for heating work, wind speed low or likely to be affected by ending an ice age, and day length within a range. Other conditions might exist, and should be thought through.

Does this mean that once we can observe some details of exo-planets, that the handiwork of an alien civilization would be visible? If we see an oxygen atmosphere, there would appear to be no way to tell if it was made by native or seeded organisms. However, if the greenhouse gases were detectable, and they are not of a kind that would occur naturally, with some genetic engineering triumphs, then we might be able to pick out a planet where aliens had colonized it. This may be the only detectable signature of planetary engineering available to us.

Friday, August 21, 2015

Starship Design – Embrittlement

Flying through interstellar space at a fraction of the speed of light is like sitting still, with hydrogen atoms flying at your front end with high energy. There are a few things that happen to the shell you built the ship out of.

Hydrogen and metals do not get along too well together. As your speed increases, interstellar gas, mostly hydrogen, will cease just being butted aside like a bow shock, but will start entering the shell material. It will work a bit like ion implantation, when an ion gun shoots positively charged ions into a target.

At a ship velocity of 0.01 c, the equivalent beam of protons is coming at about 40 kev, at 0.1 c, at nearly 5 Mev, and at 0.25 c, over 30 Mev. The latter is enough to produce nuclear transmutation. All three will produce damage to the metal or ceramic of the shell structure, by dislodging atoms from their existing structure, making vacancies and interstitials, which are extra atoms in the material structure. These two changes are called point defects, and they can move and collect to create structural weakness and damage. The shell will likely be very cold as well, which may complicate the process.

Some of the protons will only lodge themselves in the shell material, not making any changes to the existing atomic arrangements. This happens at the lower energies, and at the Mev energies of higher speeds, not so much. The protons will lodge in the shell, but only after doing some ricocheting off the other atoms, moving them to new and likely less useful locations. If the shell was surface treated, the protons could also undermine the surface treatment by moving the added atoms. This happens in the outer micrometer of material.

Protons, once embedded in the shell material, can often move around, and sometimes collect in a location to magnify the effect of their being there. A location with multiple protons becomes a site where the strength of the material is significantly weakened, as the protons affect the bonding of the original shell material. This is called hydrogen embrittlement. It does not occur in all metals, and the effects on unique shell materials would have to be determined.

The implantation of hydrogen in some other potential shell materials might lead to different problems. In steels with carbon content, hydrogen tends to combine with the carbon, making methane, which dissociates from the shell material and migrates to form tiny bubbles, undermining the strength of the material. If some sort of resin was used in the shell, it might suffer the same problem, only worse. Ceramics without any carbon would be free of this problem, but might suffer from others. Hydrogen bombardment of ceramics is not a typical experiment, so information on the effects are scarce.

At a speed of 0.01 c, running through the normal interstellar gas density of 0.3 atoms/cc, there will be a deposition of about 3 10^16 atoms/cm2. For a speed of 0.1 c, 3 10^17, and for 0.25 c, 7 10^17. These are enough to cause structural defects to multiply, and possibly long before the end of the first year, the outer layer of the shell will start to fail and probably flake off. At lower speeds, perhaps a micrometer a year would be lost, and at higher speeds, some tens of micrometers. This is nothing to worry about for a trip of 100 years, amounting to a loss of a millimeter at the worst.

As noted in the post on nosecone heating, there are large gas clouds in the galaxy, Bok globules, with a hydrogen density thousands of times more than the average interstellar gas. These range in size from about a half light year to thirty light years, and are gravitationally bound blobs of gas, that may sometime form one or more stars, or may have already formed some. Running through these clouds would make the problems of embrittlement and ion damage much more severe and likely intolerable.

A Bok gobule of five light years in diameter would take five hundred years to cross at 0.01 c, but only 25 years at 0.25 c. However, either of these situations would result in a material loss from the outer surface of the shell of a millimeter or perhaps several. Weakening the outer surface of a material that is only a few millimeters thick might result in failure of the material, but something ten or more millimeters should be able to withstand a single crossing of such a Bok cloud. This adds mass to the shell however. If the vessel in question is only a small probe, a few meters in diameter, the additional weight and mass, plus the resulting propellant mass, is not great, but for a colony ship, it is a lot. A much better solution is simply to never plan a course which penetrates a Bok globule.

Stars are believed to form in Bok globules, and they do not migrate out of them immediately. Hot stars blow them away, but lower temperature stars would still be embedded in one for a period after they begin burning. What matters is the differential speed of the star as compared to the Bok globule. When formed, this speed is likely to be zero. The differential speed would change due to the effect of nearby stars and clouds, and unless the center of mass of the Bok cloud was exactly where the star was, they would begin to pull apart. This process might be of the order of a million years. That means that long before the rubble orbiting the star had time to coalesce into planets, the star would be out of a Bok cloud.

This coalescence time is of the order of ten to a hundred million years, so very likely the globule and the new solar system would be in quite different places. There doesn’t seem to be any reason why an existing alien civilization would want to visit a solar system which was in the process of forming planets. The question is somewhat intriguing however. Would it be possible for the civilization to nudge some early asteroid in the new solar system so it was ejected from the solar system in the direction of their origin solar system? The ejection speed would likely be so slow that a hundred thousand year delivery time might result. It would be a very fanciful scenario to imagine an alien civilization obtaining resources by propelling asteroids from other solar systems toward their own, and then capturing them there.

Thursday, August 20, 2015

Chemotrophs and Energy

In a previous post, it was discussed how a simple path for life might be comprised of an initial self-replicating molecule, leading through piecewise steps to the first pre-Archaea cell. Energy was not discussed. It was assumed instead that there would be free energy available in the initial duplication of the initial self-replicating molecule. However, going much beyond that might require than an energy source be tapped.

The only energy source available at such an early stage of life is chemical energy. Thus the initial self-replicating molecules, either before or after a film membrane was evolved, would need to become chemotrophs. There have been a few unconfirmed reports of radiotrophs, which gain energy from nuclear radiation, but they need to live at a nuclear reactor site.

On Earth, chemotrophs have been found which extract energy from hydrogen sulfide, elemental sulfur, ammonia, hydrogen, ferrous iron, and lower valence state manganese. Others consume methane. Most of the known chemotrophs use oxidative reactions, in other words, they are aerobic, even in the deep ocean. Since free oxygen was not present in the early atmosphere on Earth, and probably would not initially be on alien ‘habitable’ planets, life must have initially evolved with anaerobic chemotrophs. Some use H2 instead of O2. The two types known include those which consume sulfate and those which consume carbon dioxide. The sulfate-using Proteobacteria are found underground in sulfate rock formations, and the carbon dioxide ones, Methanopyrus, is found by undersea vents. These may be the two places where life using chemical power could originate. There are currently four other known anaerobic chemical pathways used by organisms to gain energy for life, inhabiting these and similar environments. These may be the first types of higher-energy cellular organisms on our planet.

Once the use of a chemical power reaction occurs, a boost in survivability would occur, and also a huge increase in what is possible to evolve. Prior to the first use of chemical power from one of these sources, only reactions which have surplus energy could be evolved. But when these chemical power reactions become part of the cell’s armamentarium, the next step is energy storage, in a chemical such as ATP. And once such energy is available it can be transferred from whatever chemical receives it in the cell to specific reactions in the cell, meaning a wide variety of energy-requiring reactions can take place. In short, the evolutionary step to allow a chemical reaction producing energy into the cell and the next one to store it somehow open up a vista of possibilities for evolution.

So far, there have been no difficult transitions envisioned in our hypothetical pathway to advanced life. Three conditions have been noted. One is the amino acid soup, another is a substrate that a self-replicating molecule could adhere to, and the third is an energy source, either in the solution or the substrate. At this point in the pathway, a long time is needed for the primitive cells to mutate and evolve sufficiently to start to produce cells similar to ones we are now familiar with. The self-replicating molecule at the origin of this, which turned into something having one coding for a gene, not synthesized with any intermediary, that produced cell wall molecules, has to slowly evolve to be a solely coding mechanism. There has to be the evolution of countless proteins that do countless jobs inside the cell. It is possible to say that a fourth condition is the continuation of a favorable environment for evolution of single cells.

These four conditions do not appear to be very unique demands that would reduce the likelihood that planets in a habitable zone would develop single-celled life. Organic molecules, a rock surface, some chemical reaction to produce energy, and aeons of time are the four. Fossils on earth show signs of early cells about four and a half billion years ago, only a few hundred million years after the planet coalesced. Chemical energy is nice, but it is only available in restricted locations, whereas solar photons are available everywhere except the ocean deeps and the subsurface. Fossil evidence implies that a couple of hundred million years after cells formed, some sulfate-reducing bacteria supplemented their energy source with a early type of photosynthesis, IR-based, which assisted in the sulfate energy cycle. These might arise on planets around K type stars as well as G stars like the sun.

The journey to visible photosynthesis, involving the generation of oxygen, took a billion and a half more years to achieve. Chlorophyll is a difficult compound to evolve. Once cells became higher-powered, even more evolutionary options arose, and complex cells, possessing internal membranes, arose first. Then intercellular communication had to be evolved which allowed multicellular life to arise.

The next environmental requirement is a land surface. Between the development of primitive cells and the emergence onto land there are no new conditions, only time. Everything is produced from the two energy sources, chemical and photonic, plus the various molecules and elements found in the ocean and the seabed, including along the coastlines. The only Great Filter concept here is duration and stability. The oxygen which is needed for even higher powered reactions is produced by the descendants of the primitive cells.

There are different elements used in some of the evolutionarily more recent biomolecules, but they do not show the attributes of a Great Filter than would prohibit life from passing a certain stage of growth on alien planets. The distribution of elements is determined by two processes which should be the same in the various planets of the galaxy. One is the original synthesis inside stars and supernovas; this is not planet-dependent. The other is the formation of the crust of the planet, and this is governed by the constituents that congeal to form the planet. There does not seem to be much reason to think that there would initially be, in the protoplanetary disk encircling a new star, much differentiation of elements. The differentiation comes later when light and volatile elements cannot be retained by a planet because of the interaction of the mean temperature and the gravity of the planet. Thus, for example, if there is iron on a planet, there should be a sprinkling of magnesium and manganese and other elements which might be incorporated by cells. So the appearance of trace elements in cellular biochemicals would not be a Great Filter.

To summarize, once some elementary conditions are met for primitive cells to form, nothing new is needed until land organisms spring up. Everything in the oceans that more complex cells need should have been there when primitive cells arose. Energy sources are one of the elementary conditions, ranging from a variety of chemical energy sources up to the spectrum of solar photons. Only time is a Great Filter after this. How much time is determined by the global rate of mutational experiments.

As noted elsewhere, the time needed for an evolutionary step on Earth is only a clue as to what time would be needed on another planet, because the mutational experiment rate might be different. The rate is proportional to two things, the prevalence of subjects, for example, cyanobacteria, and the rate of mutation per cell. If the mutations are caused by internal conditions, such as fluctuations inside a cell when it is in the process of replicating, and occur at a fixed rate, the prevalence of subjects is the only factor. The rate of internally generated mutations might not be equal on different planets. For example, a planet with an ocean at 50 degrees C might have a significantly higher mutation rate than one with an ocean at 10 degrees C. On the other hand, if the star is a G5, with more UV photons, there might be a larger externally caused mutation rate than if the star were a K5. Thus, comments about hot stars not being able to produce life are true, but the threshold where the line is drawn might be higher because of the effect of induced mutations.

Just to complete this discussion, if the mutation rate, externally caused by UV photons, is too high, extinction will be the result instead of a more rapid evolution. Most mutations are fatal. The immediate result of this is that there is a distribution function of evolutionary rate from mutations induced by photons, depending on the star type, the distance to the planet, the type and thickness of the atmosphere and the mean depth of the organisms. It would be interesting to see if Earth is at the apex of this curve, in other words, if this planet had the fastest evolutionary trajectory in the galaxy.

Wednesday, August 19, 2015

The Shock of Intellos

Intellos is a name used in this blog to denote intelligent creatures designed and gestated by an alien civilization after it had mastered all of genetic engineering. The word is intended to mean more intelligent than the most intelligent non-human primates. Perhaps sea mammals are in some scale of intelligence, more intelligent than chimpanzees, and that is an interesting question that others may debate elsewhere. The use of the word here is to denote those creatures who have been designed to have the capability of speech, perhaps rudimentary, perhaps more.

Aliens are also assumed, in those civilizations which pass the roadblocks and minefields on the way to asymptotic technology, to have improved their own intelligence at least to the limits set down by naturally evolved genes, and at most to have invented new genes for more intelligence or even modified their own neurological structure for more intelligence, or even modified their own genetic structure, which involves speciation. So intellos are intellectually subordinate to any alien citizen existing at the time. Their interactions might be very intense, with intellos acting as personal servants, laborers, clerks, or any other roles that their civilization had. Intellos might have the ability to interact with the infrastructure of the city, providing it information and using it for information seeking, or on a more functional basis, such as repair or maintenance. Intellos could be everywhere, and might be used any place that robotics was more expensive or that the aliens preferred to have done by something organic.

There would be no reason to think than an alien civilization would restrict the introduction of intelligence only to organisms that looked like primates. They could have developed four-legged creatures, like a dog of today or a cat. They could be designed as ideal pets, if aliens had the inclination to have any.

The difficulty lies in identification and bonding, which is done on an individual basis. To have a servant or a pet for a long time can induce bonding, at least in the type of associative brains that we have. Sympathetic feeling for the servant or pet intello might lead to some strong desire to improve their station, extend their life and prevent demise, grant them benefits or even some rights. This is the shock of intellos. What kind of rules would an alien civilization set up to govern the treatment of intelligent creatures? Would it depend on their interaction with some individual aliens, so that the intellos who worked away from aliens would not have the same rules governing them as ones which interacted with one or more aliens on a daily basis?

The question of rules and regulations governing intellos would most likely be answered the way the alien civilization answers other questions, which is determining the consequences of the decision and the costs, and then returning to the question. Putting restrictions on the use of intellos, at least those which are not used in such a way as to induce a bonding relationship with an alien, would interfere with the benefit to be achieved and might raise the costs. Thus, rules and regulations, if done according to a cost-benefit approach, would seek to prevent damage and loss by the use of them, not to grant them privileges. For those involved in bonding, the decision might be left to the individual alien responsible for them.

That being said, it is an implication of that choice of regulations that intellos could be used for one-way space travel. One could be designed for that specific function, and possibly free from any travel restrictions that an alien might face. Thus, if aliens cannot survive hibernation for more than some period, maybe a month, designing an intello which could might be done. This means that any probe entering our solar system might have a creature in it which was not at all representative of the alien civilization which dispatched it. It might not have any will to live, but solely a will to accomplish the task that it was built for. It might be able to communicate with us, if that was the desire of the originating civilization, and if some unforeseen situation happened, and the probe fell into the custody of us or another planet’s citizens they chose to closely monitor, little of the civilization would be revealed. The probe could be self-destructed after any such communication, if that was the alien originators’ plan. If there was any reason to do so, the alien civilization could give a completely deceptive view of their nature to the destination planet’s citizens. These citizens might see something like an octopus, traveling inside liquid to abate radiation, vibration, g-loading and other star traveling nuisances, being in control of the probe, while aliens on the home planet looked completely differently and lived in an atmosphere, not an ocean.

Another implication of the existence of intellos might relate to the social infrastructure of the alien planet. It is already clear from other posts that an alien city could be very enjoyable, with a diverse and interesting life available to its citizens. Intellos could be one more means of making alien life enjoyable. They could be the means which pushes the Happy Life syndrome to one of its possible conclusions, that star travel is too bothersome, and the civilization becomes a category 3, meaning no star travel under any circumstances.

An extrapolation of that syndrome is when the civilization becomes category 4, and simply stops producing citizens. The planet might gradually be left in the hands of the intellos. Thus, the inevitable invention of intellos is a two-edged sword, and once again it becomes clear that social organization and the memes of the alien civilization become a fertile source of Great Filters. It is interesting, scientifically and observationally, to look for life on other planets, but if it proves to be true that all alien civilizations simply die out for one reason or another, leaving their planets with nothing but ruins and monuments, what benefit is that to us?

One way to cast this picture is to ask why so much expense is being spent on the hunt for other life-bearing planets or other colonizable planets compared to so little being spent on the other sciences, the ones which will help guide us through the next few centuries without butting our heads against the Great Filter which might have eliminated all the predecessor civilizations in the galaxy.

Tuesday, August 18, 2015

Is DNA the Earliest Foundation of Life?

It has been noted several times in this blog that the lack of understanding of the origin of life is a major impediment for deducing why no aliens are in evidence in our corner of the galaxy. There needs to be more work done on this, which is dependent on more funding. Let’s amuse ourselves by walking through the process.

One potential pathway for life might have been some self-replicating molecules, which then diversify and eventually become cells. All our cells are built by DNA, which controls the proteins manufactured by each cell. Proteins make up the structure of the cell.

How exactly did some self-replicating chemical become a coding for proteins, which are then used to make the whole cell? Perhaps it was the other way around, with DNA being formed first, and later it manufactured proteins, which eventually found their way to making cell walls and other components. Maybe even the cell wall was generated first, prior to DNA starting to manufacture proteins.

The basic idea for self-replicating molecules becoming something else comes from a very simple mathematical model. If you have a molecule, such as some form of DNA or something similar but simpler that can replicate itself, it will very soon become more prevalent than any molecule that simply catalyzes the production of a different molecule. One leads to exponential growth and the other, linear growth. Let’s assume there is some replication period, and at the beginning you have molecule A, which replicates, and molecule B, which produces molecule C. At the end of the replication period, you have two molecule A’s, and one molecule B and one molecule C. At the end of the second replication period, you have four molecule A’s, and one molecule B and two molecule C. Exponential growth! This is a nice precursor to evolution happening via competition for sustenance. The self-replicating molecules start with a large advantage.

Even if the replication time for molecule A is longer than the production time for molecule B, A will eventually win out. So, back before life began, the oceans were essentially on a hunt for the first self-replicating molecule. Once one was found, it took over from there. Any change to the molecule which preserved its ability to self-replicate, and shortened the time, given available materials, would have given it an advantage in numbers over the slower one. Thus, not only would the oceans hunt for self-replicating molecules, they would hunt for better and better ones by tweaking the original one.

Self-replication is a tricky business, and is not exactly like catalysis. Self-replication in a stew of precursor molecules means all of the components needed have to be gathered, and put into the right place. Catalysis is often thought of as a change in the form of a target molecule, or the addition of a component to the target molecule, or the merging of two target molecules. For self-replication to work, the precursor molecules have to be held in place while the other ones are being collected. Thus there must be a binding of each of the precursors to the original molecule. When there is a collection made, then the components must be joined, or that may have occurred earlier as each component falls into place. There is also a third step. The original molecule must let go of the newly formed copy of itself.

This evokes the idea of some cycling. It is hard to imagine some control mechanism completely within the original simple molecule which releases the copy. Thus, some external, environmental cycling would have to take place. When the cycle changed is not a concern, as any time after the new copy was completed, it would work. The cycling would determine the replication time, if the average time needed for collection was smaller than the cycling time. If the inverse held, the original molecule would release its components before a copy was made. If some joining had occurred, the released parts would be further along toward becoming a copy that they were before they were transiently collected by the original molecule.

Changes of temperature, pH, salinity, pressure or the presence of other molecules could create this cycling. There was certainly many examples of cycling on early Earth, from diurnal heating, tides, interaction of fresh water flows from rivers with sea water bodies, winds stirring up the upper layers, geostrophic flows, annual changes, and likely many others.

Could a molecule something like a very short strand of DNA have been the original self-replicating molecule? DNA is formed of a string of amino acids, and these molecules are believed to form in several environments, including in clouds in space. In cells, DNA does not self-replicate as there is a polymerase which performs that task. But perhaps a simplified DNA could self-replicate. If so, self-replication would be done and evolution is ready to take off, but what about DNA’s other tricks, such as producing proteins for things like cell walls. There is apparently a gaping chasm between self-replicating pseudo-DNA and the cell walls of Archea, the first known cellular organisms.

The chasm might be overcome by considering substrates. If one end of the self-replicating molecule developed a chemical method of binding to some surface, it might have a large evolutionary advantage. While free-floating, it is swept along with all the surroundings, and essential components for self-replication might be nearby, but never brought into contact. If the molecule was bound on one end to some surface, such as a grain of sand or a rock, the flow of the water past the binding point would sweep these components into the self-replicating molecule. Almost no living creatures in the ocean fails to take advantage of this process; even jellyfish move through the water or change the water inside themselves.

Once adherence was achieved, evolution would favor stronger adherence if the initial bonding to the surface was only transient. This would not have to be part of the self-replication process if a second process was evolved to deal with adherence, the catalysis or formation of some molecules useful for linking the molecule and the substrate. In other words, if one form of self-replicating molecule shed some other molecule, perhaps made as an incomplete copy of itself, which would serve to hold the molecule and the substrate together, then this one would have an immediate immense evolutionary advantage. If the production of the linking molecule could occur multiple times, and if each one of these linking molecules was tied to the other ones as well as to the substrate, a type of chemical pad would evolve. Then adherence would grow stronger, provided only that the linking molecule could attach to the substrate, to other copies of itself, and to the end of the self-replicating molecule. The generation of such as molecule by the incidental production of partial copies seems a simple evolutionary path to follow.

As the attachment pad was favored by evolution, it might grow. Since the molecule which formed it liked to adhere to itself, at least along the edges of the pad, sooner or later there might be enough to form a film partially detached from the substrate. This might serve to slow down water flow and allow more components for self-replication to occur. If evolution was clever enough to devise such a linking molecule that would form holes in the film, porous to the components needed by its self-replicating partner, the pad could continue to become a larger film, and voilá, a cell is formed when the pad closes on itself.

Properly permeable film formation and a self-replicating molecule which secondarily produces film molecules seems to be all that is needed for the most primitive form of cell. From here on in, the substrate can soon be dispensed with. Evolution has a new toy to play with, and here comes intelligent life. You might say that the self-replicating molecule has one gene, for a cell wall molecule. It is child’s play to imagine the cell wall becoming large enough to split into two with the self-replicating molecule doing its replication at the same time. Having multiple copies inside is probably an advantage, so the initial steps of cell duplication can be done with few modifications of the original concept.

If this hypothetical sequence of molecular changes is a good facsimile of the process that actually occurred, we can search through it for Great Filters. Clearly, cycling is necessary, so a planet which was phase-locked to its sun and had no satellite might not be a candidate for life. Perhaps a large satellite is necessary; the idea that the moon is necessary for life, or at least strongly facilitates its origination, is popular. Since our satellite is particularly large as a fraction of the planet’s mass, it might be rare in the galaxy. The current hypothesis for the origin of the moon is a collision between the proto-earth and another planet. Such collisions are probably quite rare, since the cross-section of the planet compared to the size of the empty space in the inner solar system is very small. The process of planetary collision has not yet been worked out in any detail. Perhaps most of them make such changes in planetary orbits that staying inside the habitable zone is rare following such a collision. This really has the markings of a Great Filter.

The other requirement is a soup of amino acids. Experiments have shown lightning can form them; it is thought that meteors and comets have some. Perhaps they are easily produced by a variety of mechanisms. The mechanisms by which they might form should be investigated more intensely, as they seem to be fundamental to the origin of life. Amino acid broth does not seem to warrant being a Great Filter, so the score is one for two.

If this hypothesis about the origination of life, that it goes backwards from what might initially be thought, it would be easy to prove that it existed. Just take some very simple DNA-like molecules, plunge them into a bath of amino acids, and fool around with the conditions, like temperature and salinity, to try and get the originator prototype to attach to a replica strand. Finding one might take several trials, but these are easy to do and cheap as well. Then dissociation experiments could begin. This is far simpler than looking around the planet for interesting life-origination sites.