| A collision 160 million years ago of two asteroids orbiting between Mars and Jupiter sent many big rock chunks hurtling towards us, including the one that zapped the dinosaurs, scientists say. |
科学家们称：1.6亿年前，在火星和木星之间运行的两颗小行星发生碰撞，使得很多大块的岩石飞速冲向地球，其中包括毁灭了恐龙的那块岩石。 |
| Their research offers an explanation for the cause of one of the most momentous events in the history of life on earth, a 10 kilometre-wide meteorite striking Mexico's Yucatan Peninsula 65 million years ago.Many scientists believe that catastrophe eliminated the dinosaurs, which had flourished for about 165 million years, and many other life forms. |
恐龙的毁灭是地球生命史上最重要的事件之一。科学家们的研究为该事件的发生原因提供了一个解释：6500万年前，一块厚度为10英里的陨石撞击了墨西哥尤卡坦半岛。很多科学家们认为：那次巨大的灾难消灭了恐龙和很多其他形式的生命；在此之前，恐龙已经在地球上活跃了1.65亿年。 |
| They say this event then paved the way for mammals to dominate the earth and the eventual rise of humankind. |
科学家们说，当时这一事件为哺乳动物掌控地球打下了基础，最终导致了人类的兴起。 |
| The impact is thought to have triggered a worldwide environmental cataclysm, expelling vast quantities of rock and dust into the sky, unleashing giant tsunamis, sparking global wildfires and leaving earth shrouded in darkness for years. |
科学家们认为，那次撞击导致了全世界范围的环境灾难，向空中喷发出大量的岩石块儿和尘埃，引发了大规模的海啸，引起全球范围的野火燃烧，使地球多年被包围在黑暗之中。 |
| US and Czech researchers used computer simulations to calculate that there was a 90% probability that the collision of two asteroids - one about 170 kilometres wide and one about 60 kilometres wide - was the event that precipitated this disaster. |
美国和捷克的研究人员利用计算机模拟进行了计算，结果为：两颗小行星，一颗厚度约170英里，另一颗厚度约60英里，发生了碰撞，促成了地球上那次突如其来的灾难；这种可能性为90%。 |
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The collision occurred in the asteroid belt, a collection of big and small rocks orbiting the sun about 180 million kilometres from earth, the researchers report in this week's issue of the journal Nature. |
研究人员在本周的《自然》杂志上报道：那次碰撞发生在小行星带，那里有许多大大小小的岩石围绕着太阳旋转，距地球约1.8亿公里。 |
| The asteroid Baptistina and rubble associated with it are thought to be leftovers, the scientists says. |
科学家们说，他们认为小行星“班普提斯蒂纳”及随其飞行的碎石是碰撞后的残余物。 |
| Some of the debris from the collision escaped the asteroid belt, tumbled toward the inner solar system and whacked earth and our moon, along with probably Mars and Venus, says one of the researchers Dr William Bottke of the Southwest Research Institute in Boulder, Colorado. |
研究人员之一、科罗拉多州波德西南研究院的威廉·波特克博士指出，一些源自碰撞的残余石块逃出小行星带，朝着太阳系内部跌落，重击了地球和月球，很可能也撞击了火星和金星。 |
| Deadly collision |
致命的碰撞 |
| The collision is believed to have doubled for a while the number of impacts occurring in this part of the solar system. And while the bombardment of this region of the solar system due to this shower of debris peaked about 100 million years ago, the scientists say the tail end of the shower continues to this day. |
科学家们认为，这次碰撞曾经使太阳系内部区域的撞击事件加倍。他们指出，碎石如阵雨般轰击太阳系的这个区域，尽管在约1亿年前已经达到轰击高峰时期，但阵雨的尾声一直持续到今天。 |
| Bottke says many existing near-earth asteroids can be traced back to this collision. |
波特克说，很多现存的近地小行星都可以追溯到那次碰撞事件。 |
| The dinosaur-destroying meteorite plunged into Mexico's Yucatan Peninsula and blasted out the Chicxulub (pronounced CHIK-shu-loob) crater measuring about 180 kilometres wide. |
毁灭恐龙的那块陨石重重地砸入墨西哥尤卡坦半岛，砸出了希克苏鲁伯陨石坑，经测量其口径约为180公里。 |
| The researchers looked at evidence on the composition of this meteorite and found it consistent with the stony Baptistina. |
研究人员在这块陨石的组成成分上调查证据，发现其成分跟小行星“班普提斯蒂纳”一致。 |
| Moon crater |
月球的陨石坑 |
| The researchers estimate that there also was about a 70% probability that the prominent Tycho crater on the moon, formed 108 million years ago and measuring about 85 kilometres across, was also carved out by a remnant of the earlier asteroid collision. |
研究人员估计，月球上著名的第谷陨石坑形成于1.08亿年前，直径约85公里，也是那次较早小行星碰撞造成的。这种可能性为约70%。 |
| Dr Philippe Claeys of Vrije Universiteit Brussel in Belgium, who was not involved in the research, says the findings are "clear evidence that the solar system is a violent environment and that collisions taking place in the asteroid belt can have major repercussions for the evolution of life on earth". |
比利时布鲁塞尔自由大学的菲利普·克雷斯博士没有参与这项研究。他指出：“这些发现提供了确凿的证据，说明了太阳系的环境是异常残酷的，发生在小行星带的碰撞可以对地球生命的进化产生重大影响。” |
| Bottke emphasises that point. "Dinosaurs were around for a very long time. So the likelihood is they would still be around if that event had never taken place," he says. "Was humanity inevitable? Or is humanity just something that happened to arise because of this sequence of events that took place at just the right time. It's hard to say." |
波特克也强调了这一点。他说：“恐龙曾经生存了很长时间。所以说，如果不发生那次碰撞的话，恐龙可能仍然存在。人类的存在是不可避免的吗？还是仅仅由于在合适的时机发生了这一系列的事件，人类才碰巧兴起来的？这很难说定。” |
