alien civilizations and energy -- 7/3/19
Today's selection -- from Disturbing the Universe by Freeman Dyson. Some of us think days or weeks into the future. Some of the most thoughtful among us reflect on what might happen years into the future. The Soviet astrophysicist Nikolai Kardashev (b. 1932) thinks thousands of years into the future. He has developed a theory of measuring a civilization's technological progress -- the Kardashev scale -- by measuring the amount of energy that civilization is able to harness. This theory has three distinct types:
"The Russian astronomer Kardashev has suggested that civilizations in the universe should fall into three distinct types. A type 1 civilization controls the resources of a planet. A type 2 civilization controls the resources of a star. A type 3 civilization controls the resources of a galaxy. We have not yet achieved type 1 status, but we shall probably do so within a few hundred years. The difference in size and power between types 1 and 2, or between types 2 and 3, is a factor of the order of ten billion, unimaginably large by human standards. But the process of exponential economic growth allows this immense gulf to be bridged remarkably rapidly. To grow by a factor of ten billion takes thirty-three doubling times. A society growing at the modest rate of one percent per year will make the transition from type 1 to type 2 in less than 2500 years. The transition from type 2 to type 3 will take longer than this, since it requires interstellar voyages. But the periods of transition are likely to be comparatively brief episodes in the history of any long-lived society. Hence Kardashev concludes that if we ever discover an extraterrestrial civilization, it will probably belong clearly to type 1, 2 or 3 rather than to one of the brief transitional phases.
|Type 2 by Equiliari|
"In the long run, the only limits to the technological growth of a society are internal. A society has always the option of limiting its growth, either by conscious decision or by stagnation or by disinterest. A society in which these internal limits are absent may continue its growth forever. A society which happens to possess a strong expansionist drive will expand its habitat from a single planet (type 1) to a biosphere exploiting an entire star (type 2) within a few thousand years, and from a single star to an entire galaxy (type 3) within a few million years. A species which has once passed beyond type 2 status is invulnerable to extinction by even the worst imaginable natural or artificial catastrophe. When we observe the universe, we have a better chance of discovering a society that has expanded into type 2 or type 3 than one which has limited itself to type 1, even if the expansionist societies are as rare as one in a million."