论文部分内容阅读
①恐龙兴起于23亿年前,曾横行地球1.6亿年之久,然而却在6500万年前倏然消失了。②在墨西哥尤卡坦半岛的6500万年前的地层中,科学家发现那里铱的含量超过正常量的几十倍乃至上百倍,这引起了科学家的好奇心。因为在地球上,铱的含量非常稀少,但是在小行星上铱的含量却比较丰富。而这样高浓度的含铱量,在地球上通常只有在陨石中才可以找到。据科学家推测,大约6500万年前,有一颗直径达10千米的小行星以每秒20千米的速度在尤卡坦半岛与地球相撞。这次撞击所释放出的能量非常巨大,撞击产生的
1 The dinosaurs rose 2.3 billion years ago and once struck the earth for 160 million years. However, they disappeared 65 million years ago. 2 In the stratum of the Yucatan Peninsula in Mexico 65 million years ago, scientists discovered that the content of plutonium there was more than a few dozen or even a hundred times the normal amount, which caused the curiosity of scientists. Because earthworms are very rare, the content of earthworms on asteroids is abundant. And such a high concentration of earthworms can only be found on the earth only in meteorites. According to scientists, about 65 million years ago, an asteroid with a diameter of 10 kilometers collided with the Earth in the Yucatan Peninsula at a speed of 20 kilometers per second. The energy released by this impact is very large, and the impact produced