VOA慢速英语2019 小行星袭击致恐龙灭绝的说法添加新证据

New Details on Asteroid¹ Strike That Killed Off the Dinosaurs²

Researchers say they have discovered new details about the day an asteroid hit Earth and killed off the dinosaurs.

研究人员表示，他们发现了小行星袭击地球那天致恐龙灭绝的新证据。

Scientists believe the asteroid struck the Earth about 65 million years ago near what is today Mexico’s Yucatán Peninsula.

科学家认为，一颗小行星在约6500万年前袭击了地球，遇袭地位于今天的墨西哥尤坦半岛附近。

The force of the massive asteroid crash is estimated to have been equal to the strength of about 10 billion nuclear bombs. The U.S. Space Agency NASA has estimated the strike created a huge crater³ about 180 kilometers wide and 900 meters deep.

据估计，这颗巨型小行星的撞击威力相当于100亿颗核弹。美国太空机构美国国家航空航天局（简称NASA）估计，这次撞击产生了一个180千米宽、900米深的巨坑。

The event is believed to have caused widespread wildfires, earthquakes and ocean waves, or tsunamis⁵. It also released chemicals into the atmosphere, leading to severe cooling that harmed many living things.

人们认为这起事件引发了大规模山火、地震和海浪波或海啸。同时，这起事件还使化学物质被释放到大气层，由此引发的严重降温导致许多生物受到伤害。

Scientists blame this climate-changing event for causing the extinction⁶ of more than 70 percent of plant and animal life. In addition, all dinosaurs, that were not bird-like, died out.

科学家认为这起气候变化事件导致超过70%的动植物灭绝。除此之外，这起事件还致非鸟类恐龙灭绝。

The crater remained hidden until the late 1970s, when it was first discovered beneath the ocean by a team searching for petroleum⁷. The theory about an asteroid causing the extinction of the dinosaurs was first presented by two American scientists in 1980.

撞击坑直到上世纪70年代末期才被发现，一个探索石油的小组最先在海底发现了这个巨坑。小行星导致恐龙灭绝这一说法最先由两名美国科学家在1980年提出。

Studies based on materials collected over the years from off the coast of the Yucatán Peninsula led most scientists to agree that an asteroid struck in that place. In 2016, a team went to the area to drill down into the ground beneath the crater to bring up rock samples.

研究人员利用多年来从尤坦半岛沿岸收集的材料进行了研究，这些研究使大多数科学家一致认为，一颗小行星袭击了这一地区。2016年，一个小组前往该地区钻入巨坑下面的土地，以提取岩石样本。

One of the leaders of that team was Sean Gulick, a research professor at the University of Texas Institute for Geophysics. He also led a new study that researchers say provides more evidence and details about the destruction caused by the asteroid.

该团队的其中一名负责人是肖恩·古利克，他是得克萨斯大学地球物理研究所的研究教授。他还领导了一项新研究，研究人员称这项研究为小行星导致毁灭这一说法提供了更多证据和详细信息。

The study involved the examination of more than 130 meters of rock believed to have built up in the seconds and hours after the asteroid strike. The findings were recently published in the Proceedings⁸ of the National Academy of Sciences.

这项新研究对超过130米的岩石进行了检查，据悉这是在小行星撞击后数小时内堆积形成的。这项研究结果于近期发表在《美国国家科学院院刊》上。

“It’s an expanded record of events that we were able to recover from within ground zero,” Gulick said in a statement. “It tells us about impact processes from an eyewitness⁹ location.” He added that the rock record “offers the most detailed¹⁰ look yet” into the period immediately after the asteroid impact.

古利克在声明中表示，“这是我们可以从袭击地收集的延伸记录。它告诉了我们目击地点的冲击过程。”他补充说，岩石记录提供了小行星袭击之后那段时间的“最详细信息”。

The researchers noted¹¹ that the buildup of material was one of the largest in Earth’s history. The materials and formations in the rocks provide evidence of what was happening in the environment right after the event.

研究人员指出，这是地球有史以来规模最大的物质堆积之一。这些物质和地层岩石提供的证据说明了那起事件之后的环境变化。

By examining the rocks, the team found evidence that most of the material that filled the crater after the strike was produced where the impact happened. This included materials that were vaporized from the blast. Some of the material was carried in by seawater pouring back into the crater from the surrounding Gulf¹² of Mexico.

该团队在检查岩石后发现，撞击发生后巨坑里堆积的大多数物质是撞击发生地产生的。这包括爆炸后被汽化的物质。一些物质由从墨西哥湾附近回流到巨坑中的海水所携带。

The researchers also found evidence of burned material, sulfur¹³ and dust. They believe these substances were vaporized and entered into the atmosphere. They said that these substances blocked the sun’s heat and caused the Earth to cool.

研究人员还发现了燃烧过的物质、硫磺和灰尘等证据。他们认为这些物质遭到汽化后进入了大气层。他们表示，这些物质阻挡了太阳的热量并导致地球降温。

The team also found material they believe came from the fungal breakdown¹⁴ of wood within or just above layers of sand. This also showed signs of trees and plant life being drawn¹⁵ into the crater by resurging waters, likely caused by a huge wave, or tsunami⁴.

该团队还发现了一种物质，他们认为这种物质来自砂层或以上林地的真菌分解。这同时表明，树木和植物被翻腾的海水卷入了巨坑中，而这很可能是巨浪或海啸引发的。

Sean Gulick said the evidence suggests that a large heat blast, followed by a period of intense cooling killed off the dinosaurs. “We fried them and then we froze them,” he said.

肖恩·古利克表示，这一证据表明，一起大热爆炸后发生了持续一段时间的激冷，导致恐龙灭绝。他说，“我们先炸了它们，随后又冰冻了它们。”

Gulick noted that the study provides clear evidence that the dinosaurs did not die from the asteroid impact. Instead, the research suggests they did not survive the resulting climate conditions.

古利克表示，这项研究提供了明确的证据，证明恐龙并不是死于小行星撞击。相反，研究表明恐龙没能在撞击引发的气候状况下存活。

“The real killer¹⁶ has got to be atmospheric¹⁷,” Gulick said. “The only way you get a global mass extinction like this is an atmospheric effect.”

古利克表示，“真正的凶手肯定是大气。只有大气效应才能导致这种全球性大规模灭绝事件。”

Words in This Story

asteroid – n. a rocky object that goes around the sun like a planet

crater – n. a big hole

extinction – n. when a type of animal no longer exists

drill – v. make holes in hard materials with a machine

impact – n. the force or action of one object hitting another

location –n. a specific place

vaporize – v. to turn from a solid or liquid into a gas

fungal – adj. caused by a fungus¹⁸

resurging – adj. the rising again into activity

1 asteroid   

n.小行星；海盘车(动物)

参考例句：

• Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
• It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。

2 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

3 crater   

n.火山口，弹坑

参考例句：

• With a telescope you can see the huge crater of Ve-suvius.用望远镜你能看到巨大的维苏威火山口。
• They came to the lip of a dead crater.他们来到了一个死火山口。

4 tsunami   

n.海啸

参考例句：

• Powerful quake sparks tsunami warning in Japan.大地震触发了日本的海啸预警。
• Coastlines all around the Indian Ocean inundated by a huge tsunami.大海啸把印度洋沿岸地区都淹没了。

5 tsunamis   

n.海啸( tsunami的名词复数 )

参考例句：

• Our oceans are alive with earthquakes, volcanoes, and more recently, tsunamis. 海中充满着地震、火山，包括最近发生的海啸。 来自常春藤生活英语杂志-2006年2月号
• Please tell me something more about tsunamis! 请您给我讲讲海啸吧！ 来自辞典例句

6 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

7 petroleum   

n.原油，石油

参考例句：

• The Government of Iran advanced the price of petroleum last week.上星期伊朗政府提高了石油价格。
• The purpose of oil refinery is to refine crude petroleum.炼油厂的主要工作是提炼原油。

8 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

9 eyewitness   

n.目击者，见证人

参考例句：

• The police questioned several eyewitness to the murder.警察询问了谋杀案的几位目击者。
• He was the only eyewitness of the robbery.他是那起抢劫案的唯一目击者。

10 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

11 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

12 gulf   

n.海湾；深渊，鸿沟；分歧，隔阂

参考例句：

• The gulf between the two leaders cannot be bridged.两位领导人之间的鸿沟难以跨越。
• There is a gulf between the two cities.这两座城市间有个海湾。

13 sulfur   

n.硫，硫磺（=sulphur）

参考例句：

• Sulfur emissions from steel mills become acid rain.炼钢厂排放出的硫形成了酸雨。
• Burning may produce sulfur oxides.燃烧可能会产生硫氧化物。

14 breakdown   

n.垮，衰竭；损坏，故障，倒塌

参考例句：

• She suffered a nervous breakdown.她患神经衰弱。
• The plane had a breakdown in the air,but it was fortunately removed by the ace pilot.飞机在空中发生了故障，但幸运的是被王牌驾驶员排除了。

15 drawn   

v.拖，拉，拔出；adj.憔悴的，紧张的

参考例句：

• All the characters in the story are drawn from life.故事中的所有人物都取材于生活。
• Her gaze was drawn irresistibly to the scene outside.她的目光禁不住被外面的风景所吸引。

16 killer   

n.杀人者，杀人犯，杀手，屠杀者

参考例句：

• Heart attacks have become Britain's No.1 killer disease.心脏病已成为英国的头号致命疾病。
• The bulk of the evidence points to him as her killer.大量证据证明是他杀死她的。

17 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

18 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。