[Color Layer]ノードを使うやり方もある。[Layers]＞[Color Layer]で出し、クリックして設定。[レイヤー種]を[グラディエント]にして、[ブレンドモード]は[アルファ]、[入力パラメータ]は[Distance to Camera(カメラからの距離)]に設定したら、キーを1つ作成し、グラディエントバーの上が黒、下が白となるようにする。消したい距離に合わせて下のキーの[パラメータ]値を入力する。それに合わせて[終了]欄の値も調整すると分かりやすい。
If extraterrestrial intelligent beings exist and have reached a high level of technical development, one by-product of their energy metabolism is likely to be the large-scale conversion of starlight into far-infrared radiation. It is proposed that a search for sources of infrared radiation should accompany the recently initiated search for interstellar radio communications.
At present the material resources being exploited by the human species are roughly limited to the biosphere of the earth, a mass of the order of 5 × 1019 grams. Our present energy supply may be generously estimated at 1020 ergs per second. The quantities of matter and energy which might conceivably become accessible to us within the solar system are 2 × 1030 grams (the mass of Jupiter) and 4 × 1033 ergs per second (the total energy output of the sun).
First of all, the time required for an expansion of population and industry by a factor of 1012 is quite short, say 3000 years if an average growth rate of 1 percent per year is maintained. Second, the energy required to disassemble and rearrange a planet the size of Jupiter is about 1044 ergs, equal to the energy radiated by the sun in 800 years. Third, the mass of Jupiter, if distributed in a spherical shell revolving around the sun at twice the Earth's distance from it, would have a thickness such that the mass is 200 grams per square centimeter of surface area (2 to 3 meters, depending on the density). A shell of this thickness could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside.
One should expect that, within a few thousand years of its entering the stage of industrial development, any intelligent species should be found occupying an artificial biosphere which completely surrounds its parent star.
さて、問題の形状についてだが、この中でダイソン自身は「an artificial biosphere which completely surrounds its parent star（その親星を完全に囲んだ人工生物圏）」と書いている。「biosphere（生物圏）」であって 「sphere（球）」ではない。全文を確認してみると、実はこの論文では構造物の形状や数については触れられておらず、「sphere」という単語も出てこない。唯一、「distributed in a spherical shell revolving around the sun（太陽の周りを回転する球殻状に配置）」の箇所で「spherical shell」と表現しているだけである。
1) A solid shell or ring surrounding a star is mechanically impossible. The form of “biosphere” which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star. The size and shape of the individual objects would be chosen to suit the convenience of the inhabitants. I did not indulge in speculations concerning the constructional details of the biosphere, since the expected emission of infrared radiation is independent of such details.
"A shell of this thickness", he wrote, "could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside". This remark gave to readers the misleading impression that the habitat of an aliencivilization would be a big round ball with a star at the center. Various science-fiction writers adopted this notion of a big round ball inhabited by aliens and gave it the name "DysonSphere". Dyson used the phrase "artificial biosphere" to describe the habitat of an aliencivilization. He was well aware that the artificial biosphere could not be a big round ball. A big round ball, whether rotating or not, would be mechanically too weak to support its own weight against the gravity of the star. He imagined the artificial biosphere to be a cloud of inhabited objects orbiting a star, surrounding the star densely enough to absorb all the starlight, but with the orbits carefully arranged so as to avoid collisions.
Well, it was really a joke which is completely misunderstood, but anyway what really happened was 40 years ago, I published a one-page note in the Journal of Science, which was called, “Search for Artificial Sources of Infrared Radiation”. The idea was that, you might have intelligent people in the sky or intelligent creatures who are actually pursuing a vigorous life but won’t interested in communicating. We had just a year before that, Frank Drake had started listening for radio signals from aliens and that was fine as long as the aliens were trying to communicate. But it occurred to me that you might want to detect aliens, even if they were not communicating and there was a way to do it and that would be to look for infrared radiation, which is essentially waste heat. So if there is a society who has suffered a population explosion and is growing very large or has just a very highly developed industry, it is compelled by the laws of thermodynamics to get rid of the waste heat. You can't exist without getting rid of waste heat and that has to be radiated into space. So you will see that heat radiation was infrared. So I suggested that people actually start looking in the sky with infrared telescopes as well as radio telescopes, so that was the proposal. But unfortunately, I added to the end of that the remark that, what we are looking for is an artificial biosphere, meaning by biosphere just a habitat that something that could be in orbit around the neighboring star where the aliens might be living. And so the word biosphere didn't imply any particular shape; however, the science fiction writers then got hold of this and imagined that biosphere means a “sphere”, it has to be some big round ball and so out of that, they came with these weird notions which ended up on Star Trek.
—Oh, yes, yes. In fact just based on secondary counts, I had imagined some giant sphere whose function was to capture all of the energy of the sun, so that none would go to waste, is that completely erroneous?
Well, except it shouldn't be a sphere of course, it should have been, but I imagined in fact a swarm of objects surrounding a star and that would be the way to use all the starlight and so it would look essentially from the outside rather like a dust cloud and actually this was invented not by me, but by Olaf Stapledon, the science fiction writer who wrote in the 1930s. So indeed if you really want to give a name to it, it should be the Stapledon Sphere rather the DysonSpheres.
One of my daughters sent me a tape of that program afterwards and so I watched it. Oh, yes, it is very clearly labelled and actually it was sort of fun to watch it, but it is all nonsense but it is quite a good piece of cinema.
To exploit these resources fully, a technological species must convert the available matter into biological living space and industrial machinery arranged in orbiting shells around the stars so as to utilize all the starlight. There is enough matter in a planet of the size and chemical composition of Jupiter to form an artificial biosphere exploiting fully the light from a star of the size of our sun. In the galaxy as a whole there may not be enough planets to make biospheres around all the stars, but there are other sources of accessible matter which are sufficient for this purpose. For example, the distended envelopes of red-giant stars are accessible to mining operations and provide matter in quantity far more abundant than that contained in planets. The question remains whether it is technically feasible to build the necessary machinery to create artificial biospheres. Given sufficient time, the job can be done. To convince myself that it is feasible, I have made some rough engineering designs of the machinery required to take apart a planet of the size of the earth and to reassemble it into a collection of habitable balloons orbiting around the sun.
邦訳書の訳文「恒星のまわりを回る球殻」は「orbiting shells around the stars」で、球という意味は入っていないはずの「shells」が「球殻」と訳されてしまっている。同じく「太陽のまわりを回る多数の居住可能な球殻」は「a collection of habitable balloons orbiting around the sun」なので、こちらでは「habitable balloons」が「球殻」に訳されている。そして案の定、「Jupiter（木星）」を間違えて「土星」と訳していた。
Not only was every solar system now surrounded by a gauze of light traps, which focused the escaping solar energy for intelligent use, so that the whole galaxy was dimmed, but many stars that were not suited to be suns were disintegrated, and rifled of their prodigious stores of sub-atomic energy.
今やすべての太陽系が、知的な利用のために、逃げていく太陽エネルギーを、銀河全体の光量が減退するくらい集中させる光捕獲用の網（ネット）に囲まれていたし、また太陽としては適さない多くの星は解体され、核エネルギーの驚嘆すべき蓄えを奪われたのだった オラフ・ステープルドン, 浜口稔 訳『スターメイカー』国書刊行会, p. 254, 2004.
“In the galaxy where the Wanderer grew in orbit, the planets are so thick around each sun they shroud its light and make a slum of space, a teeming city of a galaxy. It is the boast of our engineers, ‘Wherever a sunbeam escapes, we place a planet.’ Or they moor a field , to turn the sunlight back.
“Tens of thousands of planets around each sun, troubling each other with ten thousand tides, so that tidal harmonizing is half our civil engineering. Planets following each other so closely in the same orbit that they make elliptical necklaces, each pearl a world. You know those filigree nests of balls your Chinese carve of ivory, so that you peer and peer to find the center, and end with the feeling that there's a little of infinity locked in there? That's how solar systems look, most places.
“You haven't yet heard this news, simply because of the snaily slowness with which light travels. If you could wait a billion years, you'd see the galaxies grow dim, not by the death of stars, but by the masking and miserly hoarding of their light by the stars' owners.
“All but a tiny remainder of the star-shrouding planets are artificial. Billions of trillions of dead suns and cold moons and planetary gas giants have been mined to get the matter to make them-your Egyptian pyramids multiplied by infinity. Throughout the universe, natural planets are as rare as young thoughts.
“Your own galaxy of the Milky Way is no exception. Planet-choked suns chiefly make the great dark central cloud which puzzles your astronomers.
“A pond can fill with infusoria almost as quickly as a ditch-water puddle. A continent can fill with rabbits almost as swiftly as a single field. And intelligent life can spread to the ends of the universe——those ends which are everywhere——as swiftly as it grows to maturity on a single planet.
She pointed a claw toward the thick stars. “Those diamonds you see out there are lies. The suns that sent that bright light now are masked.”
まず1962年、ソ連の天文学者でシュテルンベルク天文研究所のヨシフ・シクロフスキーが著書『Вселенная, жизнь, разум（宇宙・生命・心）』の中でダイソンの構想を紹介していて、そこには「сферы Дайсона（ダイソン球）」という表記が確認でき、ロシア語圏ではこの時点でダイソン球という語が使われていたことが分かる（ロシア語圏での初出かどうかは不明）。この中の記述でも、やはり太陽を取り囲む巨大な殻だとされていた。以下は該当箇所だが、ロシア語は分からないので訳文は機械翻訳より（誤りがあればご指摘を）。
Поэтому вполне допустимо считать, что человек в перспективе 2,5-3 тыс. лет создаст «искусственную биосферу» на внутренней поверхности «сферы Дайсона». После реализации этого грандиозного проекта человечество сможет использовать в с ю энергию, излучаемую его «материнской звездой» — Солнцем. Необходимые для утилизации солнечной энергии машины могут быть размещены на поверхности сферы Дайсона или где-нибудь внутри ее.
“[...] According to communications received on this planet 13,595,486 years ago, the Mirt Korp Ahm embarked on a project at that time for the transformation of their home system into an enclosed sphere permitting full utilization of the solar energy. An uninhabited planet of the system was used as the source of mass for this project. The enterprise was successfully completed within a period of 150 years after receipt of first notice here. Thereafter, naturally, the home star of the Mirt Korp Ahm ceased to be detectible by conventional optical means.”
I pondered the meaning of that set of cloudy phrases without much immediate success. But to Saul Shahmoon the robot’s explanation was lucidity itself. “Of course!” Saul cried. “A Dysonsphere!”
A really thrifty civilization, Dyson said, would catch all of its sun’s energy before it was squandered. One way to do it, he suggested, was to demolish Jupiter and use its mass to build a shell surrounding the sun at approximately the distance of Earth’s orbit from the center of the solar system. Smashing up the biggest planet and rearranging its pieces this way would take a fair amount of energy all by itself: roughly as much as the sun’s total output for eight hundred years. But once the job was finished, the shell would intercept every photon of energy coming from the sun; this could be put to use as an all-purpose power source.