星空暗流 (1952)

《星空暗流》（英语：The Currents of Space），是美国作家艾萨克·阿西莫夫于1952年出版的长篇科幻小说，“银河帝国三部曲”的第二部（依出版顺序则是第三部）。在这部小说里，川陀王国已经席卷半壁银河，处心积虑继续扩展势力。

故事情节

经过若干年的星际争霸战，川陀已经席卷银河的半边江山，只剩下富甲一方的萨克世界能与之抗衡。萨克的经济命脉是其殖民地弗罗伦纳的特产，这种稀有植物无法在其他星球生长，而因为萨克赚取了全球的财富，川陀对此觊觎已久。

愚可，一个曾经过心灵改造的白痴，无人知道他的来历，只知道他突然出现在弗罗伦纳，某一天，愚可突然宣称弗罗伦纳的未日即将来临，即个银河帝国亦将遭到同样的命运。为了挽救整个银河，萨克和川陀携手合作，破坏阴谋者的奸计。

The Currents of Space is a science fiction novel by the American writer Isaac Asimov, published in 1952. It is the second (by internal series chronology) of three books labeled the Galactic Empire series, but it was the last of the three to be written. Each occurs after humans have settled many worlds in the galaxy, after the second wave of colonization that went beyond the Spacer worlds, and before the era of decline that was the setting for the original Foundation series.

Asimov stated in 1988 in the "Author's Note" to Prelude to Foundation that book #6 in the Foundation universe chronology was The Currents of Space (1952) and that it was "the first of my Empire novels." Book #7 was The Stars, Like Dust (1951), which was "the second Empire novel."

Plot summary

The story takes place during the process of Trantor's rise from a large regional power to a galaxy-wide empire, unifying millions of worlds. The approximate date is around the year 11,000 AD (originally 34,500 AD, according to Asimov's early 1950s chronology), when the Trantorian Empire encompasses roughly half of the galaxy.

The independent planet Sark rules and exploits the planet Florina which orbits the star located nearest to Sark's sun. Sark derives great wealth from kyrt, a natural plant fiber which is extraordinarily useful and versatile, but which cannot be grown on Sark or on any planet other than Florina. The relationship between the two planets is analogous to that between European imperial powers and their colonies during the 19th century, or the owners and slaves on the cotton plantations of US South: native Florinians are forced to work in kyrt fields and are treated as an inferior race by the resident Sarkites. They are also lighter-skinned than most humans on other worlds, but this is no longer viewed as significant. Memories of racism on Earth have been lost.

Attempts to break the Sark monopoly and grow kyrt on worlds other than Florina have so far been unsuccessful, because kyrt plants grown on other planets do not produce kyrt, only a useless, inferior form of cellulose; no one understands why. So Sark's wealth depends on its colonial dominance of Florina. The government of Trantor naturally wishes to add the two worlds to its growing empire.

The action centers around Rik, a man suffering from gross amnesia and apparent feeble-mindedness. When Rik gradually starts remembering his past, a political crisis involving Sark, Florina, and Trantor ensues. Rik must dodge planetary law-enforcement agents and interstellar spies as he attempts to learn his own history and identity, which the government of Sark is trying to prevent. Ultimately he learns that before losing his memory he was a "Spatio-analyst": a specialized astronaut who gathers samples of the very sparse interstellar gasses in outer space, and determines their composition. (The Spatio-analysts' slogan is "We analyze Nothing".) He also finds out that he had discovered that Florina's sun is about to explode into a nova because it is being exposed to a stream of isolated gaseous carbon atoms flowing through its region of space. The carbon atoms, besides causing Florina's sun to approach nova-stage, are also the reason kyrt grows on Florina: they are causing Florina's sun to emit a special energetic wavelength of light which kyrt plants need in order to bio-synthesize the kyrt fiber. Streams of carbon atoms ("carbon currents") are very rare in space; the reason the plants do not make kyrt when grown on planets orbiting other stars is that Florina is the only known habitable planet whose sun is located in the path of a carbon current.