万物简史 第274期:砰!(9)
Altogether it is thoughtthough it is really only a guess, based on extrapolating from cratering rates on the Moon, 据认为──虽然只是根据月球上形成凹坑的速度所作的一种推测， that some two thousand asteroids big enough to
万物简史 第275期:砰!(10)
While Gene Shoemaker was trying to get people galvanized about the potential dangers of the inner solar system, 正当尤金苏梅克试图提醒人们注意太阳系内部的潜在危险的时候， another developmentwholly unrelated on the face of
万物简史 第276期:砰!(11)
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。
万物简史 第277期:砰!(12)
This involved bombarding samples with neutrons in a small nuclear reactor and carefully counting the gamma rays that were emitted; 这项技术包括在一个小型核反应堆里用中子轰击样品，仔细计算释放出来的射线。 it was ext
万物简史 第278期:砰!(13)
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
万物简史 第279期:砰!(14)
Even among paleontologists it was not unknown. 即使在古生物学界，也不是没有这种看法。 In 1956 a professor at Oregon State University, M. W. de Laubenfels, writing in the Journal of Paleontology, 1956年，俄勒冈州立大学教授
万物简史 第280期:砰!(15)
Walter was a geologist specializing in paleomagnetism, Luis was a physicist and I was a nuclear chemist. 沃尔特是地质学家，他的专长是古磁学；路易斯是物理学家；我是核化学家。 And now here we were telling paleontologis
万物简史 第281期:砰!(16)
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
万物简史 第282期:砰!(17)
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
万物简史 第283期:砰!(18)
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
万物简史 第284期:砰!(19)
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
万物简史 第285期:砰!(20)
Hildebrand traveled to the site and decided fairly swiftly that they had their crater. 希尔德布兰德来到该地，很快就得出结论，他们找到了想要找的大坑。 By early 1991 it had been established to nearly everyone's satisfacti
万物简史 第286期:砰!(21)
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
万物简史 第287期:砰!(22)
Chicxulub is buried under two to three kilometers of limestone and mostly offshore, 奇克休留布大坑在两三公里的灰岩深处，而且大部分在近海。 which makes it difficult to study, Anderson went on, while Manson is really quite ac
万物简史 第288期:砰!(23)
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
