标签：运动简史 相关文章
So how much do we know about what's inside the Earth? Very little. 因此说，我们对地球的内部情况究竟了解多少？很少。 Scientists are generally agreed that the world beneath us is composed of four layers, 科学家们普遍认为，
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Because we can't see into the Earth, we have to use other techniques, which mostly involve reading waves as they travel through the interior. 我们无法看到地球的深处，因此不得不使用别的方法，主要包括观察波在地球内部的
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Four years later, Soviet scientists decided to try their luck on dry land. 4年以后，苏联科学家决定在陆地上碰碰运气。 They chose a spot on Russia's Kola Peninsula, near the Finnish border, and set to work with the hope of drilling
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He had discovered the boundary between the crust and the layer immediately below, the mantle; 他发现地壳与下面一层即地幔的界线， this zone has been known ever since as the Mohorovicic discontinuity, or Moho for short. 此后，这个区
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14 The Fire Below 第十四章 地下的烈火 In the summer of 1971, a young geologist named Mike Voorhies was scouting around on some grassy farmland in eastern Nebraska, 1971年夏，一位名叫迈克沃里斯的年轻地质学家在内布拉斯加
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For most of the time of the object's approach we would exist in a kind of cone of uncertainty. 在那个物体渐渐逼近的大部分时间里，我们会生活在某种无法确定的状态之中。 It would certainly be the most interesting few mo
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Still less could we send up a shipload of space cowboys to do the job for us, as in the movie Armageddon; 我们更不可能发射一飞船警察去为我们干这个活儿，就像电影《善恶大决战》里的场面那样； we no longer possess
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As one commentator has put it, fleeing would mean selecting a slow death over a quick one. 有一位评论家说，逃跑意味着在慢死和快死之中选择慢死。 The death toll would be very little affected by any plausible relocation effort,
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As anyone who has used such a pump knows, compressed air grows swiftly hot, 使用过打气筒的人都知道，受到压缩的空气马上会变热， and the temperature below it would rise to some 60,000 Kelvin, or ten times the surface temperatur
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One fragment, known as Nucleus G, struck with the force of about six million megatonsseventy-five times more than all the nuclear weaponry in existence. 有个名叫核G的碎块，其撞击威力高达6亿吨级──相当于现有核武器的总威力
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The first Anderson or Witzke learned of this setback to their careers was when they arrived at a conference in South Dakota 这对他们的事业是个挫折。安德森和威策克最初听到这个消息是在他们出席南达科他州的一次会议
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Suddenly we were at the center of things, Anderson told me, 突然之间，我们来到一大堆东西中间。安德森想起当年的情景， gleaming at the memory of it, when I met him and Witzke in their offices on a dismal, rainy morning in Ju
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I'm not mocking this at allit's vital and enlightened work; it keeps Iowa's water cleanbut with the best will in the world it's not exactly dodging lava bombs on Mount Pinatubo or scrabbling over crevasses on the Greenland ice sheet in search of anci
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He insisted that the iridium had been deposited by volcanic action, 他坚持认为，铱是由火山活动沉积的， even while conceding in a newspaper interview that he had no actual evidence of it. 即使他在一次记者采访中承认，他拿
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The results were so unexpected, in fact, that the three scientists at first thought they had to be wrong. 实际上，结果完全出人意料，三位科学家起先以为自己错了。 The amount of iridium in the Alvarez sample was more than thre
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But the thinness of the clay layer clearly suggested that in Umbria, if nowhere else, something rather more abrupt had happened. 但是，这层薄薄的黏土显然表明，在翁布里亚，如果不是在别处的话，事情发生得非常突然。
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One geologist later described it as probably the most significant paper in the earth sciences ever to be denied publication. 有一位地质学家后来把它描述成很可能是有史以来被拒绝发表的最有意义的地球科学论文。 At a
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Earth is alone among the rocky planets in having tectonics, and why this should be is a bit of a mystery. It is not simply a matter of size or densityVenus is nearly a twin of Earth in these respects and yet has no tectonic activity. It is thoughttho
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No one can say what causes the oceans' chemistry to change so dramatically from time to time, but the opening and shutting of ocean ridges would be an obvious possible culprit. 谁也说不清什么原因导致了海洋化学成分不时发生戏剧性
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In a sense it hardly matters. 在某种意义上，这项工作并不很重要。 Identifying an asteroid doesn't make it safe. 确认一颗小行星不会使它安全一点。 Even if every asteroid in the solar system had a name and known orbit, 即使
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