Monday, July 6, 2015

Aliens Live in Large Cities

No, we don’t know if there are any aliens anywhere in the galaxy. No, we don’t know if there are any that travel from star to star, and just haven’t gotten to us yet. No, we haven’t gotten any message from them wishing us a happy solstice or containing plans for starships. Yes, we can figure something out about them from what we know about science, space and technology.

One thing we know about aliens is that they are made out of atoms. Energy doesn’t confine itself without atoms, and information has to be stored and processed using atoms. So, even in the exotic scenario of mostly-energy or mostly-information creatures, they use atoms. Atoms have the bad habit of diffusing and dispersing. And this is big trouble for an alien civilization that has been around for a long, long time.

Suppose the aliens live only on one home planet. If there are only a few of them, they can live in the ecology there, limited to photon energy from their star, and letting the various processes of nature renew the planet land surface, water volumes or whatever they have. But once there are a lot of aliens, nature doesn’t work fast enough, and they have to get what they need for everything, housing or other shelter, energy systems, or health from mines or other crustal sources. That works great for a while, but these resources get depleted, and one by one, they get scarce. The geological renewal times are much longer than the civilization’s usage rate. So what do they do? They are planning on maintaining their civilization for more millennia, and don’t want to cut their population down to the small level that can live on the ecology. They have to recycle.

An alien civilization that recycles 99% of the materials it uses has extended the lifetime of the resources on the planet by a factor of 100. If they had a millennium of resources that they could reasonably get from the crust, now they have 100 thousand years. If they recycle 99.9%, they have a million years. And so on, 99.99% , ten million years. So one of the strongest drives in the alien civilization must be to recycle everything and waste nothing. Everything in the society must be directed around this one goal. Housing must be recyclable. Food and drinks must be recycled. Equipment must be recycled. Vehicles must be recycled. You get the idea. 99.99% is pretty close to 1, so frankly, nothing can be forgotten about in an alien civilization with a very long history.

Recycling would be one of the components of the alien civilization’s memes. A previous post discussed alien memes, but it was mostly about the meme for interstellar travel. This recycling meme would be even stronger than interstellar travel in their civilization, as their existence as a prosperous civilization depends on it. The recycling component would be a strongly emphasized one. In other words, young aliens would learn from early age about the importance of recycling, how to do it, how to interact with others on it, how rare and significant any exceptions to it must be – like a starship, and how it is intertwined with every aspect of life.

Of course, the aliens have a choice between a very small population living on the natural ecology, and a large population depending on recycling. This blog has not yet discussed how aliens might make this choice, but under the assumption that they want to do star-traveling, or simply maintain a culture that needs a lot of members, they need recycling.

Recycling puts two constraints on the civilization. One is that materials do not get dispersed if it can be avoided. There have to be mechanisms in place for transporting all materials back to the area or areas where recycling processing is performed. If the civilization is doing 99.99+% recycling, even dust gets recycled. This can only be done inside a hermetic environment, or very close to one. In other words, the alien civilization lives in one or more closed environments, perhaps not totally closed but nearly perfectly, in which materials can be collected, transported, recycled, transformed into useful products, and returned to the members of the civilization. In other words, they live in cities. Of a very special kind.

Suppose the aliens do not just live on one planet, but are fortunate to live in a solar system where there are multiple planets, moons, or asteroids, which they can colonize once they have learned enough technology to travel easily between these bodies. Now they have more sources of resources, and if the economics are reasonable, they can supplement the resources of the home world with certain specialties of the other solar system bodies. This might reduce the percentage of recycling they need to do, or allow a population to exist on these bodies which copies the same recycling discipline of the home world and lives on the local resources. Either way, recycling is still a credo of their meme, and they still live in an environment where it can be facilitated. To be exact, large cities.

The other reason for large cities depends on the nature of recycling. An alien civilization that concentrated on recycling would have thought through how to minimize the energy requirements for recycling, as well as cutting losses. What doesn’t have to be subjected to atom-level processing, isn’t. Equipment is designed to be disassembled, and the parts can be recycled with less processing than would be done if they were all thrown into a high-temperature vat and melted down. What separation can be maintained, will be. But nevertheless, there is a significant volume of recycling facilities that has to be built and maintained, and a small city would have a small one. Small means inefficient. If we assume the alien civilization is not profligate in their use of energy, the cities would have to be large enough so that the minimum size of recycling facilities matches the city size. There may be other reasons for a larger city, but this provides a floor value for the size of the city. Thus, aliens, except those on planets who abandon the concept of star-traveling and much, much else, and live in nature, live in large cities of a special design.

Star-traveling does not rescue them from recycling. The economics of mass transport of materials between different solar systems does not have to be worked out in detail to know that it is not feasible. Distances are long, required speeds are fast, communications are very slow, energy requirements are high, and likely many other reasons interfere with any alien civilization mining a different solar system’s resources for home use.

On the other hand, an alien civilization that learns recycling to, say, the 99.99% level has a ready-made solution for minimizing required payload mass for any large-scale interstellar vessel transporting passengers, at least some of whom are awake during the flight. Asymptotic technology in the recycling area could be transplanted readily into the starship design. Energy minimization would keep the power requirements of the ship down. Materials transport would be understood. Atmospheric filtration, if needed, would be known to the last detail.

Thus there are two overriding philosophies of design for alien starships. One is that the starship is disposable, meaning non-recyclable, and that means they would be built to a minimum size needed to perform their function, whether that be initial probe or later explorer. Every aspect of Asymptotic Technology could be used to shrink the design. Alternatively, it would be a traveling city, with all the features of an alien city, provided that the aliens spend part of the voyage awake and using the supplies of the ship.

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