Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization

First Edition

© 1975-1979, 2008 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization, First Edition, Xenology Research Institute, Sacramento, CA, 1979; http://www.xenology.info/Xeno.htm


15.3  Type III Civilizations:  Galactic Cultures

Extraterrestrial societies, frustrated by the Dyson limit, may push outward still further, spreading their influence from stellar system to stellar system across their galaxy. In time, such a culture -- comprised of many millions or even billions of Type II civilizations -- may come to dominate the entire galactic corpus. Such a "Type III civilization" could be capable of diverting the power of a hundred billion thermonuclear stellar furnaces to its own cooperative purposes.

The nature of galactic community is very much dependent upon the peculiar aspects of the physical environment. Interstellar distances are vastly greater than interplanetary ones. While a Type II culture might evolve along the lines suggested above (filling transsolar space with the artifacts of industrialization and commercial development), the endless empty regions between stars are unlikely ever to be similarly occupied. Rather, the typical Type III civilization most likely will consist of a collection of Type II civilizations. A synergistic interaction will take place giving rise to a hybrid galactic culture, a melting pot of countless millions of worlds.

A galactic community may resemble a mammoth archipelago of solar system societies, a multitude of civilized islands separated by the vastness of the oceans of space. Despite this wide dispersion, a Type III culture at its peak would command the power of a hundred billion suns -- upwards of 1037 watts. Longevity could be measured in hundreds of eons.

The time required for galactic civilization to expand to its full potential depends on the assumptions we make. Xenologists hesitate to use a simple exponential extrapolation of the 3% growth rate, because the spatial scale of interstellar expansion is qualitatively different from planetary and inter planetary scales.

If we assume, for example, that the galaxy is teeming with sentient life forms, and that none have advanced beyond the Type II stage of development, then direct interstellar colonization by any one race requires war and imperialism and so is probably not a viable ethical alternative. In this case, cultural unification will be accomplished by an exchange of valuable information and ideas using radio waves or laser beacons whose messages travel at the speed of light. This is within the limits even of a lowly Type I society such as our own. The 300-meter dish at Arecibo, Puerto Rico, could communicate with its twin located almost anywhere in the Milky Way. Clearly, Type II cultures will have the energy to transmit vast quantities of data to their interstellar neighbors.

The typical spiral galaxy spans perhaps 100,000 light-years, so the fastest news can travel from one end to the other is about 100,000 years. If we allow for search and acquisition (first you have to find your neighbors), and for the probability that at least ten exchanges would likely be necessary for cultural integration and homogenization,15 then we find that a unified polyspecies galactic civilization might conceivably begin to take form after only about a million years.*

On the other hand, what if we assume that the galaxy in question is not teeming with life? Perhaps it consists of a few scattered Type I societies, an occasional and very rare emergent Type II culture, with the great bulk of all galactic real estate consisting primarily of undeveloped planetary systems. In this case, preemptive colonization efforts by one of the Type II societies might be appropriate. This ultimately will lead to a "united" galactic culture under the leadership of a single sentient race.

How long might this take? We might imagine that a highly industrialized stellar culture could launch a large interstellar fleet of colony starships to nearby suns. They'd take along the basic implements which would enable them to set up a thriving planetary civilization. it may require 103-104 years to tame and populate the new solar system, and to build another budding Type II community around the new star. Only after the position of the original colony was secure could the pioneers seriously consider the possibility of dispatching a colonization armada of their own.

The subjugation of the galaxy would thus proceed in a series of waves, pulsing at thousand-year intervals. The alien race could sail the sea of stars at an average rate of perhaps 0.001 light-years of penetration per year. A single aggressive species could dominate an entire galaxy in less than ten million years.

While this period seems fantastically long by human standards, we must remember that the potential lifespan of a galactic civilization should run into the hundreds of billions of years. The initial colonization period represents less than 0.01% of the total lifetime of the Type III monospecies culture in question.


* While it's true that the use of tachyon communications might greatly reduce this "cultural incubation" time, it is also true that the faster a tachyon beam travels, the lower is its maximum theoretical bit rate.3119 The advantages of speed thus may be outweighed by the disadvantage of lower information transferral.


Last updated on 6 December 2008