2017 考博英语 阅读题源经济学人文章每日精析（五十）
考博英语阅读大部分博士研究生招生院校都使用《经济学人》杂志文章作为题源，考博信息网|http://www.kaoboinfo.com教育考博频道为考博生们将其中的文章进行深度分析，希望能提高大家的考博英语阅读水平，读懂长难句。
导读
每年都会有很多陨石降落到地球上，但由于地点原因我们收集到的陨石很少。对陨石含有中的矿物有机物的研究，将有可能揭示自然界有机物的形成及演化发展过程，为探索生命起源提供重要依据和线索。同时，陨石也极具收藏观赏价值。
Finding micrometeorites in city gutters
城市排水沟惊现微小陨石
An amateur enthusiast advances planetary science
业余爱好粉推动行星科学发展
Dec 17th 2016
2016年12月17日
ABOUT 4.6bn years ago, a spinning disc of gas and dust began to coalesce into balls of matter. The largest sphere, at the discs centre, collapsed under its own gravity to form the sun. Other clumps of dust, scattered around its periphery, became planets and asteroids. In planets this dust has long sincemetamorphosed into rock. But in many asteroids it is still more or less intact. As a consequence, when asteroids collide, some of it is liberatedand a small fraction of that material eventually falls to Earth as micrometeorites. This micrometeoritic dust arrives at a rate of around six tonnes a day. Spread over Earth’s surface, that amounts to just one particle per square metre each year.
大约46亿年前，宇宙中盘旋的气体和尘埃开始混合，形成一个一个的球状物体。其中最大的混合球体受自身重力影响发生爆炸，于是太阳就诞生了。而其他散落在太阳的周围的尘埃团成为了行星和小行星。构成行星的尘埃团早已硬化成岩石，但许多小行星上的尘埃团却或多或少的保留着原始的样子。因此，当小行星发生碰撞时，其中的一些气团就被释放出来，最终一部分跟随小行星以微小陨石的形态落向地球。这些微观陨石灰尘以每天六吨的频率达到地球，但除以地球的总表面积，每平方米覆盖值就如一颗粟米落入沧海，不值一提了。
Micrometeorite: n 微小陨石
Gutter：n 贫民窟;排水沟
Planetary：行星的
Coalesce：v 联合
Sphere： n 球体
Periphery：n 边缘
Metamorphosed：v 使变质
Intact：a 原封不动的
Collide：v 碰撞
Researchers go to great lengths to gather these grains, because they can reveal details of the solar systems composition and history. They normally collect them by dredging up ooze from the ocean bed, then sifting and filtering it to find a few precious particles, or by melting tonnes of ice from the Antarctic to see what precipitates. Those two locations have the advantage of being isolated and reasonably free of dust from industrial sources. Now, in a study just published in Geology, a group of researchers have identified about 500 micrometeorites from an unlikely source: gutter sediment from the roofs of buildings in two of Europe’s capital cities.
研究人员竭尽全力收集这些陨石，因为它们可以揭示太阳系的组成和历史的细节问题.。研究人员通常从深海海底捞取淤泥，筛选过滤并从中获取有价值的颗粒，或在南极融化成吨的冰查看沉淀物。海底和南极这两个地点的优势在于它们与世隔绝并且完全不受工业灰尘影响。现今，在近期出版的《地质学》的一篇研究中提出，一组研究人员发现了500颗陨石，而它们都来自一个不太可能的地方：欧洲的两座首都城市建筑的屋顶，从排水沟沉淀物中所提取。
sediment：n 沉淀物
Dredge：v 捞取
Ooze：n 软泥
Enthusiastic amateur astronomers have claimed to have found cosmic dust in such urban slurry before. Professional scientists, however, tend to be sceptical of such claims, and none has been verified. Jon Larsen, a Norwegian musician, refused to be discouraged. He collected detritus from gutters in his hometown, Oslo, and also from rooftops in several cities that he visited to play jazz or to attend conferences.
热心的业余天文爱好者声称他们之前就在这样的城市泥浆中发现了宇宙尘埃。然而，专业的天文学家却对这种说法持怀疑态度，因为没有一个曾得到证实过。尽管如此，挪威音乐家Jon Larsen却毫不气馁。他在家乡奥斯陆收集碎屑，也在他参观演奏爵士乐或出席会议的城市的屋顶收集淤泥。