Monday, November 30, 2015

Interstellar Nomads – Part 7 – Perils

Let me spoil this post by saying that it looks like a huge ship of interstellar nomads could handle all the perils the galaxy is going to throw at them. Sorry. Keep reading if you want to know the details.

Several posts in this blog attended to the perils that an alien civilization would face. These were not the social perils like revolution and war; these catastrophes were treated separately from the natural disasters that the alien civilization might encounter, or in some cases, would certainly encounter. This post just talks about the equivalent set of natural disasters that nomads about a permanent spaceship might have to deal with.

There really is only one. Something hits the ship. Something big. Just like asteroids can come in and level a portion of the surface of a planet, and send shock waves through the atmosphere of the rest of it, extinguishing many species, a big enough rock or iceball that a ship runs into would wreck it. It isn’t so much the size of the rock that makes a difference, it is the differential speed. The ship, if it is in the phase of traveling between solar systems, is moving at a fraction of light speed, perhaps 0.1% or even 1%. This means that anything impacting it has a lot of kinetic energy, seen in the rest frame of the ship.

The question is, why would they steer their ship into such a rock? Obvious answer: they didn’t see it in time to maneuver the ship to a non-collision trajectory. Why wouldn’t they see it? There are two explanations: one that they weren’t looking because of equipment failures and the other is that their equipment couldn’t see far enough out to find the rock.

No matter what they do, there will be times when they are flying blind. If they have five equivalent forward-looking sensors, and each one is down 0.1% of the time due to unforeseen and unplanned outages, all five will be down 10 to the minus fifteen of the total time. If they travel for a hundred million years, this is about thirty seconds. Thirty seconds is probably a tiny fraction of the response time they allow themselves to take care of maneuvering. In short, they are flying blind so little it doesn’t matter a whit.

What about not being able to see far enough? In other words, here are a group of genius engineers who build a ship to go so fast their best sensor cannot see obstacles in front of it. Well, slow it down.

There is another aspect to this, and that is that detection and tracking ranges for active sensors depend on the reflectivity of the object being detected and tracked. This means a small black (in all used wavelengths) object lying dead ahead would not be seen very far out. If the ship is large, the time for it to change course and miss something in front of it is also large. It is a question of the size of the maneuvering propulsors that are used to change direction. If there aren’t any, and the direction of the ship is changed by manipulating the direction of the discharged propulsive material from the main propulsor pushing the ship forward, the ability of the ship to maneuver fast is limited. Having side-facing propulsors of sufficient size is what is needed. They need to be located so they can provide some sideways thrust to the center of mass of the ship rather than being located at one end, where they would simply change the direction of the ship, leaving the main propulsor to then get the ship off the previous course onto a new safe one.

This is a question of ship design. There is a maximum size of space rock they can allow to hit the ship without major damage which would endanger its ability to reach the next stopping point, a solar system where repairs can be made. This maximum is controlled by the hull thickness, which adds to the weight of the ship and therefore to the needed size of propulsors, both main and side. On the other side of this tradeoff is the size and power of the forward-looking sensors, which essentially serve the purpose of providing maneuver time. The required maneuver time is controlled by the ratio between the equivalent side thrust, no matter how provided and the mass of the ship. Unfortunately, this tradeoff is a difficult one, as maneuver time is inversely proportional to speed of the ship and only proportional to the fourth root of the sensor power. Hard to push something much higher when you are fighting a fourth power relationship.

This means passive defenses against impact, such as a sacrificial layer on the front of the ship, and active defenses, meaning something like a laser cannon, are likely to be key players in the design of the ship. One concept is the combination of a laser scanning device with a destructive mode of operating. The cannon would scan for objects, using full power to maximize detection distance, and then operate as a deflector or disruptor in close. A very high power device would be needed for this. It would be interesting to see if the power needs of the ship aren’t really hotel and thrust components, as is almost always the initial guess, but actually sensor and disruptor power.

Another design factor is the location of critical components as far away from likely impact areas, principally the nose, as possible. If hotel functions were destroyed, the ship would be a goner. If main propulsion was all destroyed, the ship could not decelerate at the next destination solar system, and so eventually it would also perish.

The design considerations here are generic to starship design, not solely for a nomad cruise ship. The only principal difference is that the cruise ship is no burdened with the large baggage load of vehicles to descend to the surface of a planet. There do not seem to be any additional perils that would face a nomad ship when it was engaged in parking in some asteroid belt of a destination solar system, extracting resources and accumulating energy. There are design dangers, but natural dangers, no. Asteroid impact might be considered one, if the belt was dense, but if a space rock could be detected and dealt with while traveling at fractional light speed, an asteroid heading for a collision with the ship could easily be handled.

At this point in Earth’s progress toward astronomical knowledge, we don’t have much of an idea of how many rocks might be residing in interstellar space. Up to recently, we didn’t know there were rogue planets, which may have been because we didn’t know if there were planets at all around most solar systems. That uncertainty has disappeared, but all the rest remain. This information would be most interesting for contemplating a nomad ship design.

Sunday, November 29, 2015

Interstellar Nomads – Part 6 – The Seeding Mission

Sometimes ideas just call out to be combined. In a series of recent posts, the concept of interstellar nomads, a species that chooses to live in space, was elaborated. Some options of how they might do this, and what signatures they might give off for us to observe were tentatively discussed. A separate collection of posts talked about the only role for star travel was colonization, but that could take place in several ways. Depending on the memes for star travel that the alien civilization chose, they could be trying to plant the flag on exo-planets so they could have clone worlds, or something quite on the other end of the spectrum. They could be quite content with just spreading the seeds of life hither and yon around the galaxy.

The latter mission, finding planets which have not originated life, but have the capability of nurturing some sort of life if it was planted there, or finding planets that just got stuck on some plateau in early evolution, and then doing something to make life blossom there, is ideally suited for these itinerant travelers around the galaxy. The other one is not.

In the series on interstellar baggage, a jocular misnomer of course, the preparations and ship design for a plant the flag ship was described. If an alien civilization has its mind set on reproducing its own civilization on another planet, they have a lot to carry with them and a lot of work to do. Knowing all of science certainly helps, and being geniuses at everything including engineering helps a lot too, but they still need to move a good mass of stuff to the new destination.

That’s not true if you don’t mind waiting for millennia or hundreds of them to have your results, and all you care about is gardening and animal husbandry. Interstellar nomads have already figured out that, for them, life in space is ideal, and they wouldn’t want a colony planet. They don’t even want a home planet. They don’t want to go to all the trouble of setting up a planet to live on because they don’t believe in living on planets. This bored them. They live in space.

Maybe as eons pass, they clone their ship once or twice or a hundred times, so now there are many more alien civilizations living the life of the perpetual traveler in the galaxy. Since they likely visit some solar systems where there are lots of resources, as well as some where there are few, they can take advantage of the bountiful ones to copy their ship. If it is biological, this means throwing a few seeds in a vat to start. If it is mostly mechanical, they need to run their smelters and what-not for much longer than usual, while they build another ship.

This is the extent of the cloning that interstellar nomads would do. But, if they were of category A2 aliens, referring to their memes for star travel, in addition to loving the life on their cruise liner, they would want to seed whatever planets they could in the solar systems they visited. Seeding planets is somewhat decoupled in the meme they accepted as the primary goal for space travel. This collection of memes was put together with the idea in mind of aliens living on a planet and debating among themselves the prospect of going into space. This conversation, occurring around the time of the genetic grand transformation, leads to the establishment of the goals of their civilization, in the long-term, and the memes they teach their younger generation are the means by which the goals are implemented. The idea that an entire civilization can have uniform goals may seem a bit strange, given how Earth is fractionated in many, many ways, but the unification of any alien civilization reaching asymptotic technology is likely, as discussed already elsewhere.

So they have a second meme related to the details of star travel, or specifically what to do while star traveling. The original category has star travel being invented and pursued for the primary mission of fulfilling their memes for it, but with an alien nomad civilization, star travel is a goal in and of itself, and it needs no memes to drive a civilization to do it. They did it, they loved it, and they keep doing it. But the old meme they had, of the A2 variety, is still there in some of them, perhaps, and they do it while cruising the galaxy.

The costs of seeding the galaxy in this way are almost negligible. A traditional A2 alien civilization has to design a star ship, probably a series of them starting with one or more probes, send them out and wait for the communication back telling them more details about some exo-planet hundreds of light years out. Then they have to design the seeding ship, which likely is on a one-way voyage and has only robots and expendable biologicals aboard, build it and test it, and finally send it out. This could take a significant amount of their solar system resources if they lived in a less favorable one. A lot of work is involved, and a tremendous commitment on the part of the whole civilization.

On the other hand, the alien nomad ship is already there in the solar system, and if it happens to have some opportunities where a planet or a satellite could have life, they send a little probe over to drop in the right seeds. They are sitting right near the planet or satellite, so they don’t need to build any specialized hardware for observing it. The sensors already on their ship are designed to pick out promising solar systems hundreds of light years away, unless they are using the cheap traveler’s means of touring the galaxy, and something this powerful would show great details of the potential life-bearing planet or satellite without them having to leave the asteroid they are parked at. Changing the focus of a huge dish from 200 light years to 20 AU is no big deal.

It’s not really necessary to have the A2 meme be a lower priority. The two concepts, seeding planets and satellites and touring the galaxy non-stop are not incompatible. The cruise ship that the nomads use could have been originally designed as the best way to fulfill the A2 meme. It could be they didn’t really get fed up with planetary living, but that those on the planet wanted to seed the galaxy, and they figured and figured, and realized the lowest cost, highest efficiency way to do it was to create nomad ships, along with a nomad species to inhabit them. The genetic revolution would certainly allow this. Once the species for interstellar life was created, members of it would love it. It would be their home. This is how associative neural minds work. Familiarity is the basis for appreciation.

Once the A2 category home world had send out some nomad ships, their mission to fulfill their meme was done. The ships could clone themselves, so more wouldn’t be necessary and anyway, all the local good planets for seeding would have been done. The nomads would be able to extend their reach much farther, across the galaxy, and if conditions were right, even to another one. There could be no more successful fulfillment of the obligation that the earlier generations imposed on the A2 civilization than by setting up and launching a small fleet of nomad seeders.

Saturday, November 28, 2015

Robotic Fitness

Fitness has one meaning in the context of evolution, specifically, those qualities that assist an organism in replicating itself. For a bacteria, they include the ability to find food, perhaps moving to locations where it is, the ability to utilize something as food, either many things for an omnivore or unique things no other type of creature wants for a stenovore. Apologies but there is no word for the opposite of omnivore with the meaning I needed, so I made one up from an appropriate prefix and the same suffix.

A bacteria also has to be able to fend off predators or evade them or at least hide from them, or perhaps just reproduce so much that losses can be tolerated. It has to be able to survive infection, or take some actions to reduce losses from it. It has to be able to bud and form a twin. All but the last of these relate to the survival of the bacteria and the last is simply restating replication.

Similar fitness attributes, some almost identical, can be applied to every organism. These are the attributes that allow some species or subspecies to exist for a long period of time. They are the attributes favored by evolution, and also play a role in the competition between mutations to see which one will exist for the next long period of time.

There are two ways in which these can be emphasized. One is for situations where it is hard to survive, and then the survival skills are the ones selected by evolution. The other is for situations where it is easy to survive, and then the reproductive skills are the ones selected by evolution. These two classes of situations will lead to a selection, via evolution, of different and possibly contrasting choices for attributes. Survivability and fertility don’t select the same attributes, and organisms in these two different classes of situations will evolve differently.

Now let’s jump to a different environment, one in which an alien civilization has invented robots. The robots have a high degree of robotic intelligence owing to the aliens’ success in electronics, optical computing, algorithms, and other things they use to make robot brains. You could say that successive generations of robots are evolving, and there is a robotic fitness test that is making the selection of modifications. Mutations do not come from oxidation reactions in cellular milieu, nor from cosmic rays tampering with DNA, but from alien engineers tinkering with their products. Neither is the fitness test one of survival in the wild, nor of the ability to build another robot identical with the first one. It is a fitness test that measures how well the robot serves the purposes for which it is being used. Does it do the job it was created for, and what are the discrepancies, the costs, and the side effects?

If it is a single purpose robot, the metrics for measuring performance are fairly straightforward, but if it is a multi-purpose robot, some averaging over potential uses needs to be done. It takes some time to measure these things, but then the next generation of robots can be designed. The metrics certainly have an impact, but so also do coincident improvements in components that can be used to construct the robot. Software improvements go on at the same time. If algorithms are insufficient to make the robot mutations more successful, some machine learning can be employed. These involve the adjustment of parameters used in networks that make choices, or in networks that control motion, or other networks. The parameters influence how the smallest tasks are accomplished, for example grasping, and then layers are built up to coordinate small tasks into larger ones. The metric can appear at any of these levels, just as evolution would make selection based on both the accomplishment of timy tasks, like grasping, and also larger ones, such as releasing the grasp in a spear throw.

Machine learning is done against some metric. For an evolving creature, it is either survival or reproduction. For a robot, fitness means how well it accomplishes the tasks for which it was designed according to some set of metrics that the designers create. Conceivably, design could be automated and done by a robotic factory component, which would be informed of the tasks and the metrics. Perhaps it could obtain sub-metrics by observing successive generations of robots performing tasks, and using some reasoning to pick sub-metrics which contribute to the overall metric for this class of robot.

In this context, how does a robotic overlord arise who takes over the alien planet and subjugates its creators? This is a theme which appears in science fiction, and elsewhere. Does it happen by accident, where the alien engineers design the robot to do one thing, like wash dishes, and instead it does something else, like learn kung fu with which it kills its designers? Does somebody in the production process make a mistake, like putting a minus where a plus is supposed to be, and a robotic car takes off to hit as many people as it can instead of missing them all by a safe distance? Sign errors happen, of course, but so does testing, verification and validation, and checking. Does the error occur at a high level, say in the master controller of the water supply, and instead of flowing the right amount of water out of the reservoirs into the dwellings of the aliens, it puts poison into it, which it just happens to have handy because it also runs the factory making poison?

Perhaps it happens because something out of the ordinary happens, like a hurricane, which somehow taxes the robotic controller of the water supply so much that it starts drying up the city and then refuses to allow water to flow to the aliens, leaving them all to die of thirst. Or it might be more subtle, like a traffic controller that causes train crashes, killing all key programmers who understand the traffic controller system well enough to stop it.

There is no end to the scenarios that can be thought up wherein a robot of some ilk goes haywire and causes damage or death. Given an alien world where they are prevalent, that might happen. But the response to such an incident is to change the software that allowed it to happen. Imagining it to be self-generated, where the robot replaces the corrected software with the original faulty software is also possible, but all this seems so outlandish and unlikely, that it might be relegated to fantasy.

Robotic fitness is not a fantasy idea, it is the basis upon which robotics would be designed. Such a standard would not admit of any homicidal tendencies, nor any accidental problems for more than a single or a few instances, long enough to find the problem and repair it. Thus the concept of a world of mechanical beings can be understood, but only as a voluntary choice by an alien population. And then the question is why. It remains unanswered.

Friday, November 27, 2015

Common Misconceptions About Aliens

Most information mentioning aliens comes from science fiction. There are books, short stories, films, and other media. The purpose of a writer of one of these science fiction items is not to investigate what aliens might be or have to be, but to provide entertainment for his audience. Entertainment needs a plot, it needs characters, and a setting. The author may stress one of the three more than another, but they all are essential.
The characters have to be understandable. The audience identifies with them, or demonifies them. The author is trying to obtain an emotional reaction from his audience, so they will form a positive opinion of his work. This means they have to largely behave in ways which are comprehensible. Further, comprehensible means the characters must behave like humans do. Perhaps they are a bit more extreme, but the audience has to be able to recognize the humanness of their decisions, feelings, and actions. Thus the good guys and the bad guys, with some exceptions, have to have human brains even though they may have alien bodies. Perhaps part of the excitement of the book is the gradual revealing of this humanness, and the final recognition of familiarity brings a feeling of completeness and comprehension to the readers. This is a part of a success in science fiction writing.
The plot has to be interesting. The characters have to face some challenges, and strive to overcome them. Often there is a happy ending, when the favorite character succeeds in accomplishing his goal, despite the obstacles that others or nature has set. The plot has to have surprises, as if the audience can predict the entire thing from just reading the first chapter or watching the first few minutes, the item is a failure. Audiences expect surprises. A surprise is something unexpected happening, which implies that the audience is set up to expect something, and something different is portrayed. The audience isn’t going to be able to form expectations if the plot isn’t human in some way. Humans live lives here on Earth, and this forms the context in which they will form their expectations. The author has to make the connections needed so that these expectations can be found.
Science fiction is about the setting. Some technological gizmo or gizmos have to be part of the setting. If the gizmo is a magic wand, then the item is not science fiction but fantasy. If the gizmo is introduced with a few details, like scientific-sounding words or a scientific-sounding background, the magic is concealed and then the item is science fiction. In reality, much of the science is simply fiction, and the science fiction item is simply fantasy with some science words peppered here and there, often in the initial parts when the setting is being presented. It would be possible to try and keep the science fiction setting as much in accordance with what we already know about science, but that might be too constraining for the characters and the plot to fit into.

Most of the population on this planet are not scientists, have no deep understanding of science, and have not spent much time digging into it. They are not quantitative, and science is. This means that the large majority of people hearing science fiction tales cannot sort out the magic from the science, and are buried in ideas about aliens that are not as well based as they could be. Science fiction, if done well, is memorable, probably for most people more memorable than science papers.

Science writing is the other source of information for most people. This is done, often by non-scientists but often by scientists, who provide synopses of new discoveries or new inventions. Many in the audience do not have the background to make such synopses themselves from the scientific papers that cover them, nor to serve as a reviewer of the quality of the data and extractions from it, nor to know about the possible contradictions with other scientific work. It is, for much of the audience, a story, and the goals of the story-telling is not to provide all the limitations and caveats that go along with real science, but to be interesting, memorable, and pleasing to read. Furthermore, science writing is usually about discoveries rather than deductions. No aliens have been discovered. Little science writing of the usual variety can cover them. It is possible to speculate, but speculation should have rules and principles, and almost none of it does. It is based on feelings rather than on deductions. The feelings about aliens by authoritative figures can be very interesting, but not definitive.

Thus we live in a cloud of thoughts about aliens, much of which is done by authors seeking to make their science fiction works popular, which means recognizable by humans, and science writers seeking the same thing, popularity, which comes from novelty. This means it is likely that much of the cloud of ideas about aliens are simply equivalent to fantasy. They are misconceptions.

Here are four of the common misconceptions about aliens.

One is they are just like humans, with the same ambitions and goals, and the same shortsightedness. This ignores the most likely conclusion is that they have had enough time to improve their intelligence and education, so they have well thought out goals, and know how to plan and execute plans. Humans want to conquer other nations for emotional reasons. Aliens will have developed enough understanding of emotions that they will not be controlled by them. Having a spaceship full of alien troops, robotic or not, is just not in the cards. Having a mentor flying around the galaxy looking for savages to bestow technology on is not, either.

Another is that their equipment is magical. They are not constrained by kinematics, or energy, or anything. This might be based on the idea that science goes on forever and more and more barriers are overcome, including the most famous one of the speed of light. Science is not forever, it is asymptotic, and reaches its limits fairly quickly, in a period of a millennium or so. After that, everything is known. Magic simply doesn’t happen if you wait long enough.

A third is that they haven’t figured out everything important. To give some examples, they will understand music and its appreciation in a scientific manner, knowing how neurology of hearing and sound perception, rhythm and melody perception, the combinatorics of notes and probably note-free music as well, how to generate sounds of any sort whatever, pleasing to their own ears, and more. This means they have absolutely zero interest in our music. The same goes for any art or writing. They understand sociology, and would have no interest in observing us. It may be hard to appreciate, but there is nothing they could learn here, and they have much better ways to amuse and entertain themselves than watching us. And on and on, resulting in the inescapable conclusion that we are as uninteresting to them as anything else could be.

The last of the four is that they are technologically different. Technology is the same no matter who discovers it or where it is discovered or when it is discovered. It converges on one set of knowledge, and for those planets with intelligent life that pursues technology, they will all find the same things. They will all find the same energy sources, the same motive systems, the same communication systems, the same ways to recycle, the same ways to extend life, the same ways to launch spaceships, the same everything. Technology is a function of the laws of the universe, not of the locale where they are revealed. This means that if there is a reason one goes extinct, they all will. If there are reasons why they do not travel between stars, they will all find them. This means that probabilistic arguments about aliens based on the postulation that there are many worlds full of them, saying there is likely to be at least a few who want to visit us, are not valid. If one sees no reason for coming here, they all do.

It is probably much harder to write science fiction that is based on realistic expectations about alien civilizations than to write fantasy cloaked as science fiction. So, the current state of affairs, with popular misconceptions, is likely to continue for a while.

Wednesday, November 25, 2015

How Would Aliens Die?

A lot of hand-waving goes on in this blog about how asymptotic technology will reach its limit, across the board in all areas of science and engineering, most of which we either don’t consider science or haven’t invented yet, and problems that we face will dissipate. Technology will solve everything.

Obviously, there will be limits to what technology can do. The correct statement about asymptotic technology is that technology will be able to cure all curable problems leaving the incurable ones. It is not clear to us now where the boundary will lie. We understand there will be boundaries, and we can try to guess or deduce where they will be. But there is no magic, and limits will exist.

Consider longevity. Nowadays extension of life is being done by curing the various means by which death takes us. In an alien civilization, this will have gone on until all the cures have been found. People will either live forever, or they will voluntarily die, or they will involuntarily die. Those are the options.

To live forever means that two problems have been solved by the alien medical experts. One is that of wear and tear. This occurs down at the cellular level, where protein synthesis from the DNA core gradually gets more error-prone, owing to copying error and internal damage to the protein synthesis machinery. The DNA itself in any individual cell gets corrupted, gene by gene, and the errors start interfering with the cell’s viability. If the genetic engineers have left apoptosis in the cell, after some time the cell dies before it becomes dangerous, and in an immortal alien, would be replaced. But this is a reliability problem. Yes there are many cells, but they all accumulate errors, and when it comes time to replace a cell which died either from apoptosis or from the accumulation of viability problems, the cell to be copied has errors in it. So the new cell starts off with more errors than the previous generation had. It is clear where this ends. The entire cellular mass of the alien citizen gradually gets more and more full of errors on the cellular level. How would they cure this to achieve immortality? Probably by introducing new cells, stem cells perhaps, which could right the coding errors. The new introduced cells could be checked for errors before being implanted. So, there is at least a concept about how cellular coding errors and protein defects might be contained.

Wear and tear also occurs in structures at larger than cellular levels. Anything wears out. In a complex biological organism, there are methods for repairing the wear, organic methods built into the cellular coding, which rebuild organs and other structures. These would be improved, but there are limits from reliability, just as with cellular machinery. Some sort of medical intervention would be periodically required. But there doesn’t seem to be any wear problems that cannot be cured.

The second problem with immortality is finiteness. A brain, or whatever is used for the computational part of an alien’s body, can only hold so much information. Then something has to be lost if something else is added in. Perhaps alien heads, or whatever part of their body holds their brains or whatevers, could be made larger. This doesn’t solve the problem, it only postpones it. So, if genetic engineering is used to recycle brain cells, aliens would have to get used to forgetting things, and having to relearn whatever it was they knew. Over centuries, this might not be such an onerous task.

Thus, with extensive cellular therapy, some surgical intervention, some re-education and probably a few things not yet considered, aliens would not die from longevity problems unless that was the design of the society. Before getting into this topic, one thing has to be dismissed. Accidental death. Assume the alien civilization monitors accidents, and as they happen, they take steps to reduce their incidence rate, just as we do. So by the type asymptotic technology is behind them by a few centuries, their accidental death rate should be very low, owing both to the reduction of opportunities for accidents and the ability of the society to respond to one and preserve the victim’s life and bring them back to full health and capability. The same for infections.

These interventions might be expensive, in whatever currency the alien civilization used, and possibly would chew up too large a fraction of the living standards of the society. This might be looked at as a variety of scarcity of the second kind, as discussed elsewhere in this blog. There are limits as to the annual expenses of the civilization, and perhaps these medical costs would exceed it. This is not at all clear, but it is certainly an issue that might interfere with immortality, and simply reduce it to longevity. If it did interfere, then when some level of repair was needed, it wouldn’t be provided. Adios, citizen.

This leaves the other options. Would the society choose to have their citizens live forever or for a very long time, expensively, or would their memes be constructed so that they went voluntarily off to die in some calm way at some time that was most appropriate? This relates to how the alien civilization has set its goals. They could have a goal of maximizing the healthy lifespan of all citizens, but they could also have adopted one that clashed with this goal and put limits on it. If they wanted to use their resources for other things, such as interstellar colonization, they might have to cut back on medical expenses. This, of course, is not the only way an alien civilization could expend resources. They could have decided to make their home planet resources last as long as possible, meaning low population, but also lower living standards including medical remediation of wear and tear. They could have decided to have their living standards be higher for the new generations of citizens, rather than have a lop-sided level of expense, with the older citizens consuming the majority of the expenses of the civilization, mostly on medical interventions. They could have projects of their own, which we have not considered for ourselves, such as building some giant monuments meant to last for a million years on their planet, as a memorial to themselves. It may sound foolish, but there are examples we can think of here on Earth.

So to conclude, aliens would die, if they do die, of the cutoff of medical intervention or in a meme-controlled termination of life process. These last two options are not exactly exclusive of one another. The meme for voluntarily abandoning the will to live might be triggered by some wear and tear problems arising. Either way, death is more controlled and individual and society dictated than anything we have ever planned for ourselves.

Tuesday, November 24, 2015

Small Catastrophes and Minefields

Minefield is a term using in this blog with a specific meaning. It is an event or incident or side effect, or multiple repetitions of the same type of thing, which causes the alien civilization experiencing them to stop their march toward asymptotic technology. It derails progress through a specific mechanism. It might be common among alien civilizations and be the reason we do not have alien commerce dropping in here to set up their chains of warehouse stores.

The mechanism is that something happens and injures the civilization, for example by causing significant damage or death, and creates an antipathy toward more science. Science and technology must bear the blame for a catastrophe in order for it to qualify as a minefield. Other types of catastrophes, which are typically larger in scale, such as a large asteroid hitting the planet and obliterating part of it, are referred to as perils. These perils have nothing to do with technology, and can be said to be natural events. Perhaps technology is a savior for perils, in that it predicts them and allows the civilization to take measures to ameliorate the damage. The asteroid peril might be met by deflecting or destroying the asteroid, shielding some of the population, or evacuating a quorum of them to another planet in the solar system to avoid extinction. Technology is the hero here.

In a minefield, technology is the villain. In the previous post on minefields, weapons of mass destruction which are able to be obtained or even created by individuals or small groups, composed of errant, psychopathic individual, serve as a minefield. These weapons were the result of technology, and when they are stolen and used, the civilization’s reaction can be to stop the development of technology in some areas, or even across the board. If this is extensive enough and lasts long enough, the momentum of technology can be lost, knowledge can be forgotten or rejected, and the civilization descends into a more primitive, meaning less technological, state. The term plateau planet is used for a planet which starts out on the trajectory to asymptotic technology and stops somewhere, anywhere from chemotrophs to cyclotron-building, for some reason. One reason is a minefield.

The examples used in that earlier post were the result of deliberate actions on the part of individuals. Since asymptotic technology is not achieved in all fields at once, but rather there is a very different rate for different fields of science and technology, something like the neurology needed to detect early pathologies in individuals and prevent them from growing worse, there might be a development of weapons of mass destruction before the alien society becomes more calm and the citizens become more reasonable and free from psychotic tendencies. This pattern of development is inverse to what an intelligent individual might plan on, but the development of technology is not done according to an intelligent plan, but according to the individual goals of groups and factions on the planet. As noted in a different post, factionalism can result in many ways of slowing or stopping technology development, and this is one of them.

A minefield does not have to be the result of deliberate actions on the part of psychopathic individuals or warring factions. It does have to involve the actions of some aliens in the civilization, as these citizens are the ones who develop and deploy technology and a minefield has to involve technology. It can be the result of error, oversight, carelessness, calculational mistakes, laziness, inappropriate assumptions, failure to consider some aspects or threats or combinations of events or anything else, lack of attention arising from too few citizens involved or not enough funding or too short deadlines, or any of a whole host of ways that alien technologies might screw up something.

Typically, this type of technology-generated catastrophe would occur in novel areas of technology, before years, decades or centuries of experience had led to a total understanding of all pitfalls and ways to avoid them. There are certainly possibilities for a catastrophe to occur after there has been a long period of time to gain experience, and they involve not using it, via the same failure mechanisms of too short deadlines, cost cutting and so on.

When something sudden and threatening happens, the responses are often spoken of as being ‘fight or flight’. This phrase arose is the discussion of how early humans might respond to the appearance of a predator. An instantaneous choice had to be made, based on an assessment of the best chance for survival. For a technology catastrophe, the alien civilization has the same choice to make. It can ‘fight’ or work to eliminate the root cause of the catastrophe from any future use of that technololgy, so that the particular event will not recur. Alternately, it can choose ‘flight’. It can abandon the technology, and revert to something earlier. In the worst of all situations, it can choose ‘flight’ not from a specific technology, but from technology in general, or from technology of more varieties than just those which were responsible for the catastrophe.

If that technology is a key one for the advance of technology in general, perhaps being required for some reason for the improvement of living standards of the civilization, or enabling some resource to be produced or transported, or somehow else creating a large loss for the civilization, the flight from the single technology could be disruptive enough that the civilization falls into one or more traps. Scarcity is one trap that will block technology development, and the loss of a productive technology owing to the flight response might lead to scarcity. When scarcity hits an alien civilization, their response might be to contract non-sustenance activities, which includes those activities which promote the advance of technology.

Here on Earth we have not experienced the catastrophes of the first sort, where psychopathic individuals gain the ability to inflict damage on the society using some easily identifiable technology, but we have experienced some small catastrophes of the second sort. The nuclear accident at Fukushima has caused some repercussions on the development of technology. There has been the very sane and sensible response of examining existing and future designs and safety measures to ensure it does not happen again, but there has also been a ‘flight’ response to a degree, where the technology is abandoned by some factions here. It remains to be seen if this will be a debilitating phenomenon for us, but either way, it provides an example to help us understand what might happen in alien civilizations. A sufficiently debilitating response to a technical accident, perhaps worse than ones we have seen, might completely take an alien civilization out of the running in the race to the stars.

Monday, November 23, 2015

Intelligence and Sexual Selection

In a previous post, the traditional or usual explanation of the rise of intelligence in evolution was questioned. That usual explanation is that the grasping hand came first, then tool use, then intelligence in general. Maybe it was a little of one, a little of another, then a little of the third and round and round until there was some sort of stopping place for all three together, which was humans, either like us or one of our predecessors. This is all very convenient for ease in understanding, and buttresses any thoughts we might have about the dominant position of tool use, which is simply the very first step in technology, in determining society. Technological determinism is the name given to the idea that technology determines culture, but this goes further. It says technology determines evolution, at least during this phase of the rise to intelligence.

Paleontologists have discovered various fossilized skeletons which show the correlation between brain size, which somehow is related to intelligence, and other skeletal parts such as the hand, upright posture, jaw shape, and some other things. But we all know that correlation is not causality. If we are looking for a determinant of whether exo-planets that originate life will also originate intelligence, we need causality. So the initial concept of hand to tools to thought is used to denote that causality, but there is no way to prove or disprove it.

One means of proof is to show that there are no other alternatives, the proof by elimination method. But, since alternatives simply consist of other pathways being thought of and discussed, it is easy to come up with them. The previous post mentioned talked about how altruism, group living, individual recognition, observation of medicinal effects, and observation of discrepancies in behavior and other attributes, together with brain asymmetry in use but symmetry in development, when all added up together form another discussable pathway. Each of these is a short evolutionary step and all are reasonable changes, motivated by things other than the development of intelligence in general.

In this explanation, tool use did not happen and then cause intelligence, either in one step or in a gradual feedback loop. Instead, something else caused intelligence, and then tool use arose from it. It postulates a one way street from intelligence happening, as determined by brain size, neural density, convolutions of the brain, and all the other physiological correlates of intelligence, and then tool use flowing from the available computational power of the improved brain.

What else other than tool use or nutritional and medicinal use could possibly cause the brain in a species to improve in its ability to compute and figure out things? It might be nice to generate a list of all the things that a primate or alien equivalent might do that would be benefited by having a better brain. Two already listed are altruism within a small group of genetically similar animals and ability to discriminate between foodstuffs for nutritional and medicinal contributions. Another one which was downplayed was communication ability. This certainly is concentrated on one side of the brain, so it invokes the brain asymmetry/symmetry argument. It was downplayed in other posts in favor of tool use, but perhaps it is time to rethink that argument.

Besides staying alive, and perhaps more important that staying alive for a long time, is the ability to procreate. The quantitative benefit of some genetic advantage arising from a mutation is the average number of gene copies that arise from the advantage, as compared to the pre-mutation number. Does communication play a role in procreation?

In tribal units such as polygynous gorillas, where there is a dominant male, it might not. There, as in many other animals, strength and ability to combat plays the biggest role. In monogamous species, it might play some role, in that if sexual selection was based on communication ability to a degree, it would be favored. In promiscuous species, it might play an even larger role. Here, communication should be thought of as not just vocal communication, but also posturing, gesturing, posing, grimacing and anything else that involved sensory exchanges between a male and a female of the species.

Courtship displays are common in species here on Earth. They occur in species of many phyla and include both behavior and physical attributes in the lower species. If communication through the many means possible was one of the observables used in the choice of a male by a female, then communication would be a trait that was also selected by evolution. The brain of males in that species would grow to enable the communication skills that were needed to ensure mating occurred and procreation was successful. If these communication skills involved voice communication, speaking or singing, that would be enhanced; if they involved gesturing or touching or posing, those parts of the brain connected with dexterous motor skills would be enhanced; if they involved facial expressions, that part, and so on.

Some of these skills, particularly those involved with motion, or even eye-hand coordination, or tactile feedback, or other associated skills, would also play a role in facilitating tool use. Once they had been improved to some degree, they would be available for application to finding or using existing physical objects for tools, and then to modifying what was found. The other side of this coin is that, in addition to genetic changes, being involved in a courtship display might lead to some learning at a deep level, on how to use the hand to perform some particular motions, and that learning might be translatable to similar motions needed to fashion a tool or to use it for some purpose. The learning and the genetic changes might be symbiotic as well, as a gene which enables a primate or alien equivalent to learn how to manipulate objects in different ways, via analogous use in courtship displays, would be positively reinforced. The learning might be wholly done in successive attempts at courtship displays, but still be useful for tool making and use.

In short, there is a third pathway to the development of intelligence in certain types of animals that can be considered, which would not violate any paleontological insights. This pathway has a very different causality chain than either the first, tool use directly, or the second, nutritional and medicinal use, and it might have different conditions or requirements. One check to keep in mind when contemplating alternative pathways is that on Earth, no other species developed the kind of tool-using intelligence that one species of primates did. If other species have the same type of activities in conjunction with these pathways but did not develop tool use, then a reason for this would have to be developed.

Sunday, November 22, 2015

Which was First: Intelligence or Technology

The usual parade of development of intelligence in the human species has things happening thusly: first primates develop hands, meaning grasping claws, soft, with opposable thumbs for some non-intellectual reason such as they were better at climbing in forests; then the hands allow some early tool use most likely wood and then stone; then the brain develops to make more use of the tools. After this short sequence of evolutionary intelligence, the brain has gotten to the point where there is positive feedback from having it grow larger, and it does, and we as a species arrive on the planet.

This sounds like a reasonable guess, but if we really want to know if intelligence is going to evolve on different planets, which is an obvious necessary precursor to flying starshps, did it really go that way? Are there any other less obvious pathways which might be right and which might harbor completely different Great Filters, including the one that has stopped all planets but ours from even thinking about star travel?

It is not the development of large brains. Elephants, dolphins and whales all have larger brains than humans do, and while they exhibit signs of having brain power, they certainly aren’t intelligent in the same way that humans are. Some better communication skills exist, maybe great memory, but we must vote no on intelligence. There might be an argument made about the ratio of brain weight to body weight, and here man is exceeded by even some insects, birds and rodents. So a more complicated formula with brain mass and body mass might be found, but perhaps this making this quantitative misses the point.

Evolution happens in a particular direction because there is an advantage provided in reproductive ratio. If some gene change results in more copies made in the next generation, on the average, that gene change increases its share in the gene pool in a gradual way, eventually displacing competitors. Speciation happens in a gradual way, as a single animal in a species with bisexual reproduction would not be able to reproduce.

The usual argument is that each of the steps in the pathway mentioned above, hands, tool use, brain, provides some survival advantage. They interact, and there would be multiple gene changes that together provide an overall increase in reproduction ratio. This particular pathway is especially appealing to those of us who are involved with technology. Technology at the very earliest stages, involving the use of some found material or easily produced item, made from wood perhaps, plays a large role in developing intelligence, and since technologists are often proud of themselves for their technological skills, it is pleasing to think that technological skills created the creatures that are our ancestors.

What other skills or attributes could a larger brain play a role in that might also provide a relative advantage? Sensor specialization is likely not the answer. Other creatures have better sight, hearing, smell and taste, and likely proprioceptive sensing as well. Other creatures have other senses we do not have, such as the ability to navigate using either polarization or the Earth’s magnetic field, infrared vision, and likely others. Having a bigger brain volume devoted to processing these sensor inputs is not likely the driver for intelligence, or those creatures with better or more diverse senses would be the intelligent ones.

Combinations of sensors, such as the collection that involves the selection of food and makes an animal more of an omnivore, is also not likely to be the key. There are insects and animals which are more omnivorous than humans. Perhaps disease avoidance or curing is. Survival is not just a matter of finding food and avoiding large predators, but also in surviving any infections or other diseases which strike. If the brain evolved the ability to recognize sickness in a fellow creature, and then provide some particular nutrients which would ameliorate it, and help the sick creature to recover, then if there was gene similarity between the donor and the acceptor of the nutrients, and trust between them so that the sick one accepted them, some small benefit to reproductive rate for genes they shared might arise. The idea that some early primate developed something like folk medicine has not achieved currency, but food selection was certainly something that the early primate brain was good at, and if they lived in groups, recognizing other group members was as well. Recognizing changes in the appearance or the behavior or some other aspect of another member, which was an indicator of sickness, is not a large leap from the group recognition ability.

It is possible to recognize other humans based on many attributes, face being the most common perhaps, but voice, gait, gestures, and many other aspects can also be used. For example, gait can be used at distances where faces cannot be seen well. If these aspects are all integrated together in the brain as a complex able to recognize other group members in many situations, then being able to notice discrepancies that appear over short times should also be noticeable. Aging changes these aspects as well, but the changes from aging occur over longer time periods and also are similar among various members of the group. Aging changes might be easily distinguished from the rapid changes in voice or gait or speed or other aspects which denote some infection or disease is present in the observed creature.

Over long periods of time, the group might learn what herbs or other medicinal might affect the progress of the infection or disease, and if it was large enough, to pass down this information. There is some indication that certain animals understand that if they feel a certain way, they should eat some particular nutrient. Maybe that is how the early stages of such an evolutionary advantage got started.

Brain size would be pushed to understand larger numbers of medicinal and more diverse symptoms, and as it grew, other capabilities would be easier to be added. When the symmetry of the brain broke, and brains began to develop particular capabilities on one size only, this might happen more easily. Brains develop symmetrically in size, but if only a lobe on one size were involved in, say, recognizing unique herbs or being able to find them, the corresponding lobe on the other side might be available for something else, like tool use.

This would mean that tool use gets started, not because of some evolutionary feedback loop that says tool use increases survival so the gene for it is increased in frequency, but that tool use gets started by accident, in that there was some extra available computing power in the brain occasioned by something else, like medicinal use, and human ancestors just fell into using it. This more complex pathway reducing the importance of technology, but it might be right. Alternatively, there might be other pathways where brain size and complexity is forced by some other activity or attribute, and again, tool use just happens to use up some spare computational power on the opposite side of the brain.

If there is a different path to intelligence, all the previous thinking about what conditions there would have to be on an alien planet for intelligence to happen need to be reexamined.

Saturday, November 21, 2015

Transmutation As an Energy Source

Perhaps we on Earth are not as close to asymptotic technology as we think. Transmutation of elements, otherwise referred to as alchemy in ages past, might be part of asymptotic physics but we are unaware of simple means of doing it. Current methods of transmutation involve either reactors or particle accelerators. In the first, a flux of neutrons from the fission of uranium is funneled into a target, where the neutrons are absorbed and the atomic weight of the target material increased. Decay processes of the resultant nucleus lead to a nearby element, the result of the transmutation. In the second, charged particles are emitted and either directly impacted on a target medium, or used as the energy source in a neutron generator, where neutrons are freed from a nucleus like deuterium and then proceed to do the same thing a reactor-generated neutrons.

Neither of these methods is suitable for making industrial quantities of desirable elements, and they have the side effects of producing undesired radioactive elements which have to be dealt with. The cost of the equipment is also large, especially in comparison with the tiny amount of material that can be produced. The methods are used for some specialist purposes, such as the production of certain radioactive isotopes which are used in medical treatments and measurement devices used, for example, for finding flaws in cast metals. Any object other than cast metals can also be scanned, and devices like x-ray scanners can be produced based on the radioactive output of these materials. Radioactive isotopes can also be produced for power sources for interplanetary probes or remote locations on Earth. Amounts of materials produced, however, are small in comparison with industrial uses, and cleanup methods for removing co-produced radioactive isotopes must be employed before these isotopes are ready for use.

An alien civilization which used certain non-radioactive elements or specific isotopes industrially might be able to produce them in a more efficient way. At this point there is no confirmed method on Earth of doing it, but nuclear physics is not a field that has explored all the corners of science where such a method might be lurking. The theory which is used to predict nuclei properties is not solvable in most situations, and the data used in it is not all collected. Progress continues and will continue for some time.

The most elementary view of nuclear physics comes from the curve of binding energy, which is the amount of energy released upon the formation of some nucleus divided by the number of nucleons, protons and neutrons, in it. The curve is like a bathtub, with iron at the bottom, and hydrogen at one end and the transuranics on the other. Fusion produces energy by nuclei at the lower end moving toward the center, and fission does by nuclei at the upper end moving toward the center. Both of these are energy sources, the first happening in the sun and providing us with photons, and the second being used for nuclear power plants, based on the amounts of uranium we dig out of the Earth’s crust.

The curve of binding energy is better seen as a pond, with the two variables describing it being the number of neutrons and the number of protons in the nucleus. The bottom of the pond is very bumpy, not smooth, as there is a great deal of structure in a nucleus. There are no known sources of energy that arise from moving from one bump to another except for the use of radioactive elements in radioisotope power generators. The problem in using the transmutation of non-radioactive isotopes for power sources is the non-radioactivity, which is another word for stability. Nothing happens unless a means for affecting the nucleus is done, such as by hitting it with a particle.

There is a current buzz in our media about doing this, under the name of Low Energy Nuclear Reactions, and the claim is that there are pathways to releasing the energy between these binding energy bumps that do not require much input energy. No substantiated claims or confirmed theories exist, nor do any replicatable experimental setups, but a small hubbub exists concerning yet unsubstantiated claims and unconfirmed theories. These claims and theories do not have the same level of quality as nuclear physics in major institutions would require, and likely have little substance. However, that does not mean that an alien civilization, which has a complete understanding of both nuclear physics related to nuclei, and methods of concentrating energy on some particles and delivering it to a stable nucleon, could not have discovered a method or methods of exploiting the bumps in the two-dimensional surface of binding energy
The fact that we have not discovered such a phenomena is not any indication of its non-existence. A look at the extensive investigation that was required to locate higher-temperature superconductors indicates how elusive such a goal might be. Other examples for the chemical industry exist and likely elsewhere.

If the alien civilization did that, and it only worked with a few elements or isotopes, or even one only, it might serve as a power source that could replace radioisotopic power generators, or even become more widely used. If the method extended to multiple elements or isotopes, transmutation could be used to develop more substantial sources of certain isotopes, perhaps even some materials that they might use in small quantities in certain applications, such as dopants for semiconductors.

What effect might this have on our projections of star travel? Little. This source of power does not have the energy concentration of antimatter, far, far from it. It likely would not have the same power density as a well-designed reactor for an interstellar probe. But exactly how much it could provide is even more a mystery that its existence. Nothing to do but wait and see.

Friday, November 20, 2015

Interstellar Nomads – Part 5 – Sensors

Interstellar nomads comprise an alien civilization or several who have mastered long-duration interstellar flight and have simply decided not to get off the ships, but just keep traveling. This makes sense in a way, as they have done everything possible to make the starships reliable, problem-free, and durable, but also to provide the passengers a comfortable habitation. They may have done extensive speciation to adapt their life-forms to interstellar travel. If they arrived at some planet that we call habitable, they might call it un-inhabitable as it has unpleasant aspects such as gravity and an atmosphere, which they do not need or want in their current incarnation. Such a planet would just be dirt for their use, or more likely, since they do not favor mining in a deep gravity well, just something littering up the solar system. It would have been better for them if the planet had never consolidated out of asteroids.

How long an alien nomad ship would remain in a solar system depends on the resources that the solar system offers them. They could leave immediately after stocking up with enough resource, including energy, to get them to the next promising solar system, but why would they? The essence of their existence is that they are enjoying life aboard what might be a palatial space cruiser, and whether that cruiser is traveling at some fraction of lightspeed to another destination star, or it is simply orbiting one star for an extended period, makes little difference in their happiness and enjoyment of their life aboard the cruiser.

It will be generations between stars, so these nomads are not tourists, going from star to star to gawk at the planets it has, and see if they have bigger canyons or deeper oceans or funnier creatures or whatever the last one had. They see the ship as planet-bound aliens see their planet. A planet for its inhabitants is a place to live, and in fortunate places, to enjoy life. For nomads, the cruiser is the same thing. That is the center of their attention, not the refueling depots, called asteroids, that they visit out of necessity. So, orbiting around some star which has plentiful asteroids, they might just stay there until the resources get short.

There is an altenative situation, in which there are inhabitants on one of the planets who also do some traveling in space, perhaps only interplanetary, and they have some desire to interact with the nomad ship. Perhaps they regard it has hostile or simply insist on it not taking all their resources, and raise objections to its presence. Then it would be time to leave as soon as refueling was done. But since the universe is so old, and stars live so long, and evolution takes such a lengthy period, the likelihood of a coincidence of visiting a star and having an alien civilization on one of the planets just into interplanetary exploration is vanishingly small.
If the reasons for being nomads were universal, all civilizations will abandon their home planets and cruise the stars. This means there is a short window of time between asymptotic technology being achieved and the transformation of the species into a nomadic one.

When it is time to leave, the nomadic ship has to make a determination of where to go next. They need sensors to find another suitable solar system within their travel radius. This means, most likely, some large aperture devices capable of determining many details of the other solar system. It could be deployed soon after the ship arrived at a destination solar system, so that they could leave as soon as they wanted to, knowing just where to go next.

The sensors would be measuring aspects of nearby stars and their accompanying solar systems for the presence of available resources, which likely means low gravity places to get minerals. Any star high up enough in the stellar sequence produces photons, if they consume them. Otherwise, if they want to find a source of deuterium, for example, the sensor would have to be able to see if it could be found there based on direct signatures, in other words, seeing some absorption lines of it in an atmosphere of one of the planets, or on indirect signatures: where there is one thing they don’t use, there is always one they do use accompanying it.

If they use scooping ships to gather gas from the outer atmosphere of a certain type of planet, for the purpose of extracting some element or isotope they need, their knowledge of how atmospheres form and are retained would give them the knowledge to connect what they can see with what they need to know. An atmosphere with hydrogen lines would have deuterium, especially if the sun exhibits the usual ratio of emissions from these two isotopes.
Thus, a sensor with a large aperture, perhaps ways to block the sun’s output when they are looking at planets, with spectroscopic capability, in other words, just what we have today scaled up to a larger size, would probably be sufficient for them.

One implication of the requirement for these sort-of-ordinary sensors is that they would likely not be made biologically. Biology is not so precise as to be able to grow such sensors. Neither would a biological network be suitable for processing the data from it, so this facility of the ship, as probably many others, requires some mechanical/electronic components. This adds to the list of things they need to find on their asteroid depots, and to the things they need to be able to extract, purify, and adapt to the uses for both sensors and computation.

So, sensor design for a nomad ship for solar system scanning is probably not difficult, but it does impose a new list of resource demands, as well as manufacturing demands, assembly demands, maintenance demands, and computation demands. So far, no obvious barriers pop out.

The ship would also need navigation sensors, to ensure it could make the trip to a destination solar system, and to ensure that it could avoid any obstacles along the way. The existence of rocks in space of varying sizes is not clear, but hitting any large one might be more damaging that they wanted to tolerate. This means some sort of avoidance sensor is needed. This is likely a much more demanding requirement than the star-tracker needed for navigation. Rocks in interstellar space are cold and therefore not good infrared sources. Finding enough power for an active sensor may be a serious problem, as the sensor would need to be able to detect small objects at large distances and then track them to determine their potential for collision. The earlier the object is found and tracked, the less fuel is needed to adjust the trajectory. The degree of adjustment needed is related to how accurately the position and course of the rock is, as it would be necessary to evade the whole zone of uncertainty surrounding the presumed location of the rock at the time of closest approach.

Thus, scanning sensors and navigation sensors are likely not worth exploring deeper, but if there really are rocks in interstellar space, avoidance sensors might present an interesting problem for the nomad ship. A second implication of the sensor discussion is that the most observable feature of a nomad ship in one’s own solar system might be the scanning sensor. It might have a large size and a large albedo, and perhaps some curious aspects, such as glinting. More things to look into.

Thursday, November 19, 2015

Antimatter Batteries

One constant of traveling at fractional lightspeeds is that you have to have the energy to do it. And you have to carry the energy around with you. On a one-way trip with no reserves, you need the energy to accelerate and the energy to decelerate. There is so little matter in space that drag won’t do it for you. So you use forward-facing thrust, which takes energy.

Lots of energy is required, and is it a show-stopper to have to carry so much energy around? Looking at a lower bound might be useful to clarify this question. Consider solely the source of energy for speed changes. A ship needs energy for much more than simply speed, but let’s simply look at this to get an idea of whether it makes everything impossible immediately.

The highest known concentration of energy as matter is an equal masss of antimatter and matter. This will serve as a generator for the lower bound on the mass needed for a power source. Suppose a ship has two tanks, one for hydrogen and another, a very special tank, for antihydrogen. Using anti-hydrogen rather than anti-protons means that those pesky problems of electrostatics don’t have to be dealt with. How good is the efficiency for tankage? Some very clever way of storing antihydrogen on a ship made of matter has to be used, and we don’t yet have much of an idea about how to do it. Maybe in a century or two we will be able to make a better estimate, but let’s use the lower bound for the tankage mass. Zero. You can’t get lower than that.

So we need to look at the mass of hydrogen and anti-hydrogen, which, if annihilated, will propel the ship to a fractional lightspeed. Suppose the ratio of the burned mass to the propelled mass is b, and then the fractional lightspeed achieved by turning the mass of the anti-hydrogen and hydrogen into kinetic energy is simply √(1-1/(b+1)2). This formula looks like this:

Interesting speeds range from 0.01 to 0.1 c, which means that the fraction of ship mass which is this hydrogen and antihydrogen that gets burned ranges from about 0.0005 to 0.05, which does seem overwhelming. This is a lower bound, where lower is almost to the point of absurdity, so a factor of 2 to 10 should be multiplied in to keep things reasonable.

At the lower end of the velocity range, 1% c, the mass of burned fuel is not really important in figuring out the total mass of the vessel. And if we double the burned fuel mass so there is enough for both acceleration and deceleration, it still is not that much. But because kinetic energy, at least in the Newtonian range, goes like v squared, increasing the ship’s speed by a factor of ten, the burnable mass that has to be collected goes up by a hundred. So the upper bound of speed makes the ship look like a giant battery, with living space a small fraction of the total. And propulsion fuel has not yet been taken into account.

This means the tradeoff between speed and travel time will be very, very important in figuring out the total energy required and the total mass of the ship. Energy costs for things like the hotel load, meaning everything for the sustenance of life and maintenance of operations, goes inversely proportional to speed, while fuel goes like the square. These calculations can be made and will likely show that the lower end of the speed range is where the ship would have to operate.

There is also a difference between an autonomous ship and one traveling between spaceports on inhabited planets. The autonomous ship has a tremendous amount of baggage to be carried concerned with its operations at the uninhabited destination planet, or asteroid, or satellite. If the ship is going to be parked in orbit and abandoned, there are some costs which can be eliminated, but if it is going to make a second run, somehow the antimatter battery has to be refueled. While the mass of the battery is not so much, making it takes a great amount of energy.

There is no antimatter lurking around in the galaxy that we know about, so no one can expect to harvest it and stick it into the battery. It has to be manufactured, and we don’t know any easy ways to do that yet. We simply know how much energy is the upper bound of what mass of antimatter is stored.

As a matter of fact, there isn’t much energy lurking around at all. There is gravity, and perhaps someday someone will come up with a scheme to extract gravitational energy in a solar system, and maybe aliens all learn this as part of their asymptotic technology, but if there is no such source, it is pretty much fusion. There is fusion you get for free, from star photons, and fusion you have to pay for, in your own fusion machine.

There has been some speculation that it is possible to do fusion in solid media, the so-called ‘cold fusion’ where deuterium fuses at room temperatures. However, the amount of energy required by a starship is so large, that sources with low production rates would simply be too inefficient to use. Large amounts of fusion power are needed to fill the batteries in any reasonable time. So hot fusion, in a star or in a power station, is needed.

Grabbing solar power for a starship is a bit different that getting it on a planet. A habitable planet has to be at a nice comfortable temperature, meaning that the solar photon flux cannot be too high. This translates into very large areas for collecting the photons. But a starship that can tolerate higher fluxes, perhaps by being extremely reflective, or which can send in a shuttle to an area of high flux, near the star, might be the better way to go.

We do not have much of an idea about how to do the other method of fusion. Some experience indicates the facility might have to be very large, but that is based, not on any successful power-producing experiments, but on designs. Whether something more reasonably sized, and capable of high power production, can be built is not known by us. If aliens with asymptotic technology can do it, then they would likely prefer it as it can be done anywhere the resources, both for the power plant and for the input fuel, exist. It may be that only deuterium can be used, and then an autonomous starship would forever be on the hunt for deuterium sources.

Wednesday, November 18, 2015

Interstellar Nomads – Part 4 – Biological Ships

It was previously noted in the blog that the genetic grand transition is likely to be a bigger revolution in an alien civilization than any other grand transition. We don’t see it coming here on Earth, because it is in some sense far away from us in some abstract distance. We are so used to thinking about mechanical devices because the industrial revolution happened long enough in the past that the implications of it have become gigantic and projections of further changes are somewhat easy to come by. Robotics is really an extension of the mechanical devices of the past, plus computing technology. Computing technology is more of a close relative of mechanical devices than of biological organisms. But once the changes start happening in the genetic arena, the relative scale of biology as compared to mechanics will become clear.

There was a post in this blog about biological factories, which are factories for making something, maybe a plastic for covering food in the refrigerator, that have no mechanical parts to it. One immediate response is to think of exceptions. What about the structure? Maybe the biological stuff would be inside in vats, and cement would be used to keep the weather off the vats.

Did you ever hear about trees? They provide structure, they grow in predefined patterns, they work well exposed to weather, and they don’t require much maintenance. Could the genetic engineers in an alien society, well past the genetic grand transition, come up with some seed that would grow into a building? It would have entrances, it would have bark on the outside or something similar, maybe scales, it would have a roof over the top perhaps made of photosynthetic sheets, that look like giant leaves. So why use cement when you can plant a seed?

Possibly some alien would have to carry another seed inside to be a parasite on the treebuilding, which absorbed carbon dioxide, water, and some sap from the treebuilding and produced plastic goo, which flowed down a surface to make the wrap. Of course, there might be no use whatsoever in the alien civilization for plastic wrap to cover food in the refrigerator, because there aren’t any refrigerators as food comes in pipes to residence, and leftovers go out through pipes to be recycled. The pipes might use peristalsis instead of a pressure head to move things, or maybe some other more interesting mode of propelling material on the insides in one way only. They would repair themselves, feed themselves through smaller pipes down to capillaries, and in addition there would be small creatures that move through the pipes to check on their health and perform whatever medical treatment was necessary. Veterinary science, if you can call repairing biological buildings, factories, piping, recycling facilities, and lots more veterinary work, would be the biggest employer, possibly. But it would be largely automated as well, if you can call having interestingly designed organisms doing veterinary medicine automation. We are a little short of words in Earth languages to describe what might be entirely commonplace in an alien civilization; this reflects the fact that we are a little short of imagination on what might be there.

If the aliens have discovered that biological things are better in many ways than mechanical things, and they responded by designing everything to be biological with some few exceptions, they would be accustomed to doing all their design work in the framework of biology. How to you want an organism to look and work to perform some certain task? And then how to arrange for the ontogeny, is a seed enough, or is there something more advanced, like a multi-genetic combination – several different but compatible cells that together grow to produce what is wanted?

This means they would design the ship to be the same as their cities’ infrastructure, biological. When we think of a spaceship hull, we think of some steel structure, and have to worry about embrittlement from the particles that the ship rams into going at a fractional light speed. If the hull was just bark or something like it, and it was renewed automatically periodically, there would be less worry about it fracturing and shattering into pieces, endangering the innards of the ship. Maybe there would be multiple layers there, with a growing layer and a static layer. Perhaps there would be organisms that swept over it, consuming the outermost layer and bringing it back into the ship for recycling.

A nomadic ship is like a city, just with no gravity but propulsion engines instead. To keep the crew alive and happy, the same functions need to be performed. If the aliens can engineer a city which is 50% biological, or 90%, or even more, they could do something similar for a starship. No one would think of propulsors capable of accelerating a starship to some fraction of light speed as biological, at least no one on Earth. No one would think of a power plant, either fission or fusion, as biological. These parts of the ship would have to be mechanical, and undergo the types of maintenance and repairs that are most familiar to us. Conceivably there could be organisms that do the repairs, perhaps some beings that are largely immune to radiation and could survive it for long enough to do whatever was necessary. Alternatively, there could be multiples of each of these, multiple propulsors and multiple power plants, and there would be reliability in the numbers, and no repairs done in interstellar space, but only when orbiting some asteroid in some solar system where there are material sources for things that have to be replaced.

A nomadic ship doesn’t just have to survive the voyage though space, it has to carry with it the capability of gobbling up whatever resources, including energy sources, that it needs when it parks somewhere in a solar system. This may mean small shuttle vessels able to go down to an asteroid with 0.01 g maximum, and dig out something from the rock there. These small vessels might be designed and grown in the same way the mother ship was, largely biological, with some power and propulsor pieces somehow bonded to the rest of the ship.

Just how visible would a nomadic ship in our own solar system be, for example if it was parked, consuming an asteroid? If it was biological, the albedo of the bark-like outer surface might be low. It might have a thermal signature showing about the same temperature as nearby asteroids. There might be insufficient separation between the asteroid and the ship to show up on most observations, or alternatively, the ship could simply dock down on the asteroid, with no use of shuttles. This would be invisible to us at this time, unless we were lucky enough to have one of our space probes going by the asteroid and noticing this funny thing protruding on one side of it. We do take pictures of many larger asteroids using high power telescopes, but so far, no one has noticed anything looking anything like an alien ship. Perhaps next year?

Monday, November 16, 2015

Interstellar Nomads – Part 3 – Speciation

Deliberate speciation is the creation of a new species, for any reason at all. It has been used in this blog in connection with an alien civilization reaching the limits of the chromosomal arrangement that evolution provided them, and proceeding to change it, so as to achieve some advantages in any of a number of attributes. They could have recognized that their immune systems could be so much better without the baggage of the old chromosomes. They could have made the discovery that they could re-introduce regeneration into their species if they just changed the chromosomes. They could have wanted to have better DNA repair capabilities but the old chromosome design was holding them back. And so on. This decision has profound implications for the alien civilization, although at first sight it seems like a simple, logical decision to make.

There is a separate and completely distinct reason for an alien species to do deliberate speciation. If it manages to colonize other planets or satellites in its own solar system, it could become clear that a new species would be better suited to live there. The obvious parameter is gravity. If their solar system has an inhabitable world, but one which has 1.4 times the gravity of their own, this may be too many negative effects on their own species. Early heart attacks and other medical problems might be the first to be noticed. Breathing the different atmosphere that a higher gravity planet holds onto might be the second one. But if they modified their species to cope with that gravity, or better, to be ideally designed to live in that gravity, including the atmosphere change and anything else needed, then their colonization attempts would be much more successful. This also has profound implications. On the high gravity planet, there is a new species there which may have less connection with the home world. The new species of citizens might have a hard time visiting the home world. This alien civilization has divided itself in two, inside its own solar system.

The same thing could happen if there are lower gravity planets orbiting their sun. Light, spindly creatures that need much less to breathe might be the best design for a creature to live on this planet. The same would happen for a satellite they considered marginally habitable. There could even be a solar system with three habitable places, and the originating alien civilization that arose on one of them could split itself into three distinct varieties. They could communicate easily, as they would keep the same language. They could ship things from one planet to another, perhaps with the transport ship just going into orbit and ferrying down materials or whatever on a shuttle. But the three species do not visit with each other.

In a previous post, it was considered that some alien civilization might make a decision we consider bizarre. They would choose to live their lives out on a starship. Of course, the idea of having intergenerational starships is not so outlandish. What is different is that they have no inclination to get off that starship and move the civilization back onto a planet. If you stop to think about it, if a starship is designed for multiple generations to live on, and they are living happy, content lives there, as would be the goal of the design, why stop? What is the big deal about having a planet?

Now consider the alien civilization that is making the decision to become star-traveling nomads. They are designing ships, planning to build them, figuring out how to navigate, determining how to actually make it possible to maintain the ships for humongous periods of time, figuring out if there are any areas of the galaxy they certainly wanted to avoid, and thinking, thinking, thinking about how to pull this off, with no details forgotten that might cause them a catastrophe or even end their civilization.

They would most likely get around to thinking about speciation. If there are any organisms besides the aliens themselves on that nomad ship, they might just redesign them using their genetic knowledge. They are long past asymptotic genetics, meaning they know how to do anything that is possible to do, whether it would be achievable by evolution or not. And likely, there are many more things that evolution would never create that they could create, perhaps hundreds or thousands of times as many possible organisms, only a few of which might somewhere, on some planet, evolve into existence. So they might stock the ship with organisms they designed themselves.
Then they might also ask, what about us? Should we redesign our own species to make it more suited for traveling for eons between the stars? This interacts with the design of the ship itself. If they live on a planet with a certain gravity, their bodies were essentially designed to deal with the stresses of such a level of gravity, and to operate in it, and not in any other. This means, put gravity on the ship, maybe by rotating it, or change their own species to be designed for zero gravity.

Just what a species would look like if it was designed for zero gravity requires a wide imagination. Does it make sense to have weight-bearing limbs, or maybe no legs at all. Four arms, perhaps? On Earth, heads are usually the highest point of the body of many creatures. In zero gravity, there is no highest point, so where should the head go? Digestion might be assisted by gravity, so peristalsis might have to be modified. Friction on any surface would be important for moving about, but does this mean four hands or four feet? How many eyes? What wavelengths should they be sensitive to, is red enough so lighting is easier? What type of communication should there be between citizens on the nomad ship?

And then there is atmosphere? Is one needed? Here on Earth it is a given that animals use oxygen, because we have it and it is free and useful to the animal. On a nomad ship, is a different way of providing oxidizer for the fuel used for nutrition better? Then leave the ship a vacuum? Or fill it with some gas, but make that gas optional for the new nomadic alien species?

It should be obvious that any alien civilization which has made a decision to become nomads in space has a huge number of options available to them, and they might spend quite a long time preparing for this, just as they would in designing the ship.

One implication of such speciation is that they would not visit Earth, because they couldn’t survive here. If the consideration that, once the aliens have designed an intergenerational ship, they will never get off it, is valid, no aliens would ever want to visit Earth. We would be seen as a primitive bunch of creatures that might someday join the crowd in the galaxy, kind of a stepping stone to real civilization, which floats between stars, traveling forever.

Sunday, November 15, 2015

Interstellar Nomads – Part 2 – SETI Implications

The previous post started a discussion of how an alien civilization might voluntarily choose to abandon its home planet, not to seek a new one, but to live in space only, upon some starships. Just for a moment, consider that this was a logical and reasonable decision, and that all alien civilizations that get past asymptotic technology think about it and eventually decide to do it. It makes the hunt for aliens a lot different than if they were all like us, living on their home worlds and simply exploring and colonizing nearby exo-planets.

There are two currents in our society concerned with alien life. One is concerned with the origination of life on other planets, although the same considerations apply to seeded life. This current involves astronomers trying to figure out, with the help of other specialists, how to detect signs of life itself on other planets. This is the concept of biosignatures. The simple one is the chlorophyll signature, oxygen in the atmosphere. This blog has discussed the division of planets which harbor life into those which are solely full of chemotrophs and those where some surrogate of chlorophyll has taken advantage of the energy source provided by the solar photons that stream down on any orbiting planet. Chlorophyll produces oxygen, and some similar compounds may as well, and some more primitive photon-absorbers do not. We don’t seem to have the chemical knowledge yet to predict all of them and compute the relative advantages, but synthetic organic chemistry will one day get to this stage, and then we can more clearly define what the utility is of relying on oxygen in the atmosphere as a signature of photosynthetic life. For now, we look for oxygen, and it could be said the first current of alien life investigation is trying to find evidence of chlorophyll. These are the exo-plant hunters, who look at exo-planets in the habitable zone for indications of oxygen.

The other current isn’t hunting the other kingdoms, like fungi or animals. There doesn’t seem to be any biosignature arising from them that can be developed with current or near-term observational equipment. So the plant kingdom gets special attention. The other current is looking for intelli-signatures, to coin a word to mean something that can only arise from intelligent organisms. The hoary one is listening for some electromagnetic signal that sufficiently departs from natural sources that it can be seized upon as evidence of intelligent life. Another one is looking for evidence of very large structures, or in general, any gigantic engineering projects. Being so far from capable of doing such things, we don’t have much of a list to go on, and not much details for those things which are candidates for being on the list. Perhaps someday in the not too distant future we would be able to look for terra-forming, i.e., a planet which looks habitable from a temperature point of view, but shouldn’t for some reason. Or we might look for planets with climate control, which would require even finer observational equipment.

All this is rendered somewhat OBE, overcome by events, if the hypothetical assumption made at the outset of this post is true. A civilization will stay on a planet only for a few millennia, during which time it develops asymptotic technology and makes the decision to bid the planet goodbye, and become interstellar nomads. Ten millennia is such a short time to inhabit a planet, and an even shorter part of that time is when the planet might be emanating some electromagnetic radiation that could be detected. Once star travel is possible, the planet shuts down and turns the lights, and radios, off.

Our search for electromagnetics can only be successful with a nearby solar system having a transmitter, as the r-squared losses mount up and make any emanation from a distant planet too deep in the generic noise of the galaxy to be detected. Say over the lifetime of the galaxy there is a uniform probability of life originating on a habitable planet, and for the sake of the argument, assume it is high. Using ten billion years as the age of the galaxy, an intelligent alien civilization might emanate some EM transmission for a thousand, which is one ten-millionth of the total age. After that they are cruising the stars. So we would have a ten-millionth chance of listening when they are on, and maybe we could double that if we listen for a whole millennia ourselves. If there are a thousand habitable stars within the detection range of our best possible listening apparatus, whatever that might be, we would be up to two ten-thousands chance of hearing something.

So the concept of interstellar nomads, if it proves to have any merit, would essentially doom such an attempt at intelli-signature detection, at least of the type initially thought of. As for finding planetary changes, such as climate modification or terra-forming, well, they just aren’t doing that. They could care less what happens to planets, except insofar as they would be good for mining or energy sources. Building some large structure near a star? Also not interesting.

So it is worthwhile trying to determine if there could be any motivation that we have not yet appreciated for becoming interstellar nomads, as it conditions how we search for intelligent life. We would want to know if it is reasonable, and then what signatures, if any, there might be from a starship either making its way between stars, or hanging around some solar system, refueling and replenishing stocks of materials lost in the recycling process.

We don’t understand quite yet how useful it would be to mine asteroids. For an interstellar nomad ship, dropping down into the gravity well might be the last thing they would want to do, and so they would be most interested in those solar systems which have lots of the type of asteroids with things they have the largest losses of. Cleaned up solar systems might not be worth visiting, as the task of going from one to another demands a lot of resources as well as energy. One question, then, would be in what type of solar system would we be likely to find such a ship? At least then we would know where to look, provided we could develop the technology to find such systems. Right now, we can find larger planets and large dust disks. Finding small asteroids might be well beyond our capability now and in the near future. What to do?