Passage 33 (33/63) Until recently most astronomers believed that the space between the galaxies in our universe was a near-perfect vacuum.
天文学家一直认为星系间接近真空。 This orthodox view of the universe is now being challenged by astronomers who believe that a heavy “rain” of gas is falling into many galaxies from the supposedly empty space around them.
现在，天文学家相信有气体"雨"分布其间。 The gas apparently condenses into a collection of small stars, each a little larger than the planet Jupiter.
这种气体凝聚成一系列的小星体，每一个都稍大于木星(是木星吧，没有记准)。 These stars vastly outnumber the other stars in a given galaxy.
数目众多，比在星系里的星还多。 The amount of “intergalactic rainfall” into some of these galaxies has been enough to double their mass in the time since they formed.
落入一些星系的“星系间雨幕”的质量足以使这些星系的质量倍增。 Scientists have begun to suspect that this intergalactic gas is probably a mixture of gases left over from the “big bang” when the galaxies were formed and gas was forced out of galaxies by supernova explosions.
有怀疑指，星系间气体是宇宙大爆炸留下的气体混合物。当时，星系形成，超新星爆炸将气体挤出星系。 It is well known that when gas is cooled at a constant pressure its volume decreases.
衡压下，气体冷却，体积减少。 Thus, the physicist Fabian reasoned that as intergalactic gas cools, the cooler gas shrinks inward toward the center of the galaxy.
Fabian推理，星系间气体冷却，气体向星系中心压缩。 Meanwhile its place is taken by hotter intergalactic gas from farther out on the edge of the galaxy, which cools as it is compressed and flows into the galaxy.
同时，其位置被离星系边缘更遥远的较热气体所占据。这些较热气体边压缩边冷却，并流向星系。 The net result is a continuous flow of gas, starting as hot gases in intergalactic space and ending as a drizzle of cool gas called a “cooling flow,” falling into the central galaxy.
直接结果是气体的连续流动，一开始是星系间的热气，最后成为一股冷气，即“冷流”，流向中心星系。 A fairly heretical idea in the 1970’s, the cooling-flow theory gained support when Fabian observed a cluster of galaxies in the constellation Perseus and found the central galaxy, NGC 1275, to be a strange-looking object with irregular, thin strands of gas radiating from it.
冷流理论在1970年代被视为异端想法，但被F的观察所支持。 According to previous speculation, these strands were gases that had been blown out by an explosion in the galaxy.
据前推测，这些气体带曾被星系内的爆炸喷出。 Fabian, however, disagreed.
但F不同意。 Because the strands of gas radiating from NGC 1275 are visible in optical photographs, Fabian suggested that such strands consisted not of gas blown out of the galaxy but of cooling flows of gas streaming inward.
因为是可见光，所以F认为这些气体带不仅有喷出的，也有流入的冷流。 He noted that the wavelengths of the radiation emitted by a gas would changes as the gas cooled, so that as the gas flowed into the galaxy and became cooler, it would emit not x-rays, but visible light, like that which was captured in the photographs.
他推理到，冷流可发出可见光。 Fabian’s hypothesis was supported by Canizares’ determination in 1982 that most of the gas in the Perseus cluster was at a temperature of 80 million degrees Kelvin, whereas the gas immediately surrounding NGC 1275 (the subject of the photographs) was at one-tenth this temperature.
F的理论在1982年被C所支持，P星座(星系群)中的气体(即星系间气体)温度8千万K读，而NGG 1275这一星系的周边气体温度为8百万K度。
哈哈，文章还是挺有意思的。这些原本看不到的气体，温度如此之高啊! 希望最后一句的星座和星系的差别能够解决楼主的问题. | 
