【经济学人】虚空的物理学简史|2016.11.19|总第734期

MOST of the universe is empty. So it is natural that a great deal of modern physics concerns nothing—or rather the precise nature of the nothing that permeates the cosmos. Work in the past century in particular has shaken up scientists’ understanding of emptiness. Ideas about gravity and motion put in place by Isaac Newton in the 17th century were overturned by the work of Albert Einstein. The dawn of quantum mechanics revolutionised physicists’ understanding of the very small, but the theory’s conclusions were so counterintuitive that Einstein was never able to reconcile himself with them. James Owen Weatherall, a philosopher, now examines how scientists’ conceptions of supposedly empty space have changed in the light of these convulsions in his latest book, “Void”.

宇宙的大部分都是空的。自然而然许多现代物理学关心的就是虚无——更确切地说，是弥漫宇宙的虚空的精确规律。上世纪的研究成果尤其刷新了科学家们对于真空的认知。牛顿在17世纪时建立的重力和运动理念被爱因斯坦推翻。量子力学的出现彻底变革了物理学家们对微观事物的理解，但是这项学说的结论是如此违反直觉以致于爱因斯坦难以接受。现在哲学家詹姆士·欧文·韦瑟罗尔，在他最新的一本书《太空》中，剖析了科学家们对所谓虚空的理解在撼动之下如何变化。

• Uncanny 神秘的

• popping in 突然出现

• Counterintuitive 违反直觉的

Many people today imagine that, on a molecular scale, the air around them resembles a tumultuous three-dimensional game of billiards. Yet this picture, of molecules of nitrogen, oxygen and other gasses ricocheting through emptiness, is a mere 300 or so years old and has its roots in Newton’s theories. His law of universal gravitation described the attractive force between two masses in a void. But that void isfar from obvious. Before the publication of Newton’s “Principia Mathematica” in 1687, two of the most influential thinkers of the Western world, Aristotle and René Descartes, developed theories requiring space (for different reasons) to be filled with stuff of some sort.

如今许多人误认为，在分子尺度上，周围的空气类似一场激烈的三维桌球游戏。然而这幅氮氧和其他气体分子在真空中弹开的情景，仅仅有300年左右的时间并且扎根于牛顿的理论之中。他的万有引力定律描述真空中两个有质量物体之间的吸引力。但那个真空远远不是现在所公认的。在牛顿的《数学原理》于1687年出版之前，西方世界最具影响力的思想家中的两位——亚里士多德和笛卡尔，提出理论要求空间被某种物质填满（出于不同原因）。

• Tumultuous 狂暴的，激烈的

• Ricocheting 弹开

分子间有着不可描述的引力

In the late 19th century, the work of James Clerk Maxwell also seemed to rule out the notion that a vacuum was truly empty. Maxwell discovered that electricity and magnetism were linked, but he erroneously believed light waves were vibrations in an invisible “aether”. Based on this premise, he and his contemporaries incorrectly reasoned that the speed of light measured in laboratories on Earth could not be its true value since the Earth was moving through space relative to this aether.

19世纪晚期，麦克斯韦的研究似乎同样排除真空是真正的空的概念。麦克斯韦发现电与磁相互关联，但他错误地认为光波是看不见的以太中的震动。基于此前提，他和同代人做出错误推断：既然地球在和以太有关的空间中运动，在地球上的实验室里测出的光速不可能是真实值。

• rule out 排除可能性

• aether 以太

Einstein’s work would sweep away this view less than 50 years later. First, in his special theory of relativity, he claimed that the speed of light was the same for all observers, dispensing with the need for the aether. Next, his general theory of relativity would show that space could be curved and textured, like a taut rubber sheet stretched and formed by the masses of planets and stars. Quantum mechanics and quantum electrodynamics (a theory that merges quantum theory with Maxwell’s electromagnetism) would later reveal that even an apparently empty vacuum resembles, at small enough scales, a boiling sea of particles that constantly pop in and out of existence.

将近50年后爱因斯坦的研究成果扫清这一观点。首先，他在狭义相对论里宣称光速对于所有观察者是一样的，摒弃以太的必要。接下来他的广义相对论说明空间可以是弯曲和不平的，像一张绷紧的胶皮被行星和恒星的质量拉长成形。（期待您的翻译，明天会有针对这句话的读者试译详解哟~）

• textured 质地不平的，有纹理的

These are not easy concepts to describe, and sometimes Mr Weatherall is in danger of losing the uninitiated reader. A diagram or two would have helped. Nonetheless, sending the curious scrambling to Google is forgivable.

这些概念都不易描述，有时韦瑟罗尔会处于失去外行读者的风险中。一两张图表本会有所帮助。虽然如此，让抱着好奇心啃书的读者去自行谷歌也可以原谅。

空间也扭曲

More difficult to understand is the book’s failure to mention the work of any female physicists in its pages. The author mentions, for instance, Paul Ehrenfest’s parrot (which the physicist trained to say “But gentlemen, this is not physics!” during discussions of quantum mechanics) but not his wife and collaborator, Tatyana. Also missing from the account is Henrietta Swan Leavitt’s work on Cepheid variables, pulsating stars which would become a yardstick for the expansion of the universe. That means a chapter discussing the possible shapes of the universe consistent with the general theory of relativity ends without discussing what its actual shape might be in the light of such discoveries. These oversights mar an otherwise engaging and interesting account, but perhaps it is natural that a history of space should have a few gaping holes.

更难理解的是这本书没有提及任何一位女性物理学家的成果。比如，作者提到了保罗·埃伦费斯特的鹦鹉（这位物理学家训练它在量子力学的讨论会上说：“但是先生们，这可不是物理学！”），而没提他的妻子兼合作者Tatyana。同样叙述中也没有涉及亨丽爱塔·勒维特有关造父变星的成果，一类可以作为宇宙膨胀尺度的脉冲星。这意味着一章内容阐述宇宙的可能格局，与广义相对论保持一致，却以没有根据这些发现去论述作结。这些瑕疵破坏了一件原本充满吸引力的有趣作品，但是可能一段有关空间的历史有几个缺口才是自然。

• Cepheid variables造父变星

• Yardstick 尺度

编辑 ▍毛毛