VOA慢速英语--导致恐龙灭亡的小行星或曾以最致命的角度撞击了地球

Study: Dinosaur¹ Killing² Asteroid³ Hit Earth at ‘Deadliest Possible’ Angle

A new study suggests the asteroid that killed almost all the dinosaurs⁴ struck Earth at the "deadliest possible" angle.

Scientists believe the asteroid hit Earth about 66 million years ago near what is today Mexico's Yucatán Peninsula. The force of the massive crash is estimated to have been equal to the strength of about 10 billion nuclear bombs.

The climate-changing event is blamed for causing the disappearance⁵ of more than 70 percent of plant and animal life. All dinosaurs that were not bird-like died out.

What has remained a mystery for scientists, however, is whether the asteroid strike was a direct hit. The new study provides evidence that the strike resulted in the worst kind of crash for the dinosaurs.

Researchers examined data on the structure of the 200-kilometer-wide crater⁶ in Mexico where scientists believe the asteroid hit. They attempted to recreate the asteroid event on computers.

The results, recently published in Nature Communications, showed that the asteroid struck Earth at an angle of about 60 degrees.

As a result of the angle, an especially large amount of climate-changing gases would have been released quickly into the atmosphere.

The lead researcher was Gareth Collins, of Britain's Imperial College London.

"For the dinosaurs, the worst-case scenario⁷ is exactly what happened," he said in a statement. He added that the release of gases into the atmosphere started a series of events that led to the permanent disappearance of the dinosaurs.

The release "was likely worsened by the fact that it struck at one of the deadliest possible angles," Collins said. If the asteroid had hit head-on or at lower angles, less material would have been released into the atmosphere, he added.

Scientists believe the massive release of gases and chemicals into the atmosphere led to a period of extreme cold, also known as a "nuclear winter." This was caused by large amounts of sulphur particles that stayed in the air, blocking heat from the sun. The asteroid strike is also believed to have caused widespread wildfires, earthquakes and ocean waves, or tsunamis⁸.

The researchers said their models are the first to reproduce the whole event – from the first hit to the moment when the final crater was formed.

The findings seem to disprove a long-standing theory that the asteroid moved toward Earth from the southeast. The scientists said recreations based on the crater's structure showed the asteroid coming from the southwest.

The study could lead to a greater understanding about how craters⁹ are formed in general. The modeling suggested, for example, that rocks "rebound¹⁰" to fill in beneath the crater during its final formation. The researchers said the findings suggest that large craters can be formed in a matter or minutes.

Scientists continue to question how some living things were able to survive the asteroid event. Gareth Collins said the new study clearly suggests the strike resulted in "a very bad day for the dinosaurs." He added: "It makes it even more remarkable¹¹ that life survived and recovered as rapidly as it did."

I'm Bryan Lynn.

Bryan Lynn wrote this story for VOA Learning English, based on reports from Agence France-Presse, Imperial College London and Nature Communications. Caty Weaver¹² was the editor.

Words in This Story

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

angle – n. a space between two lines or surfaces that meet at one point

crater – n. a big hole

scenario – n. a situation that may develop in the future

rebound – v. the move back through the air after hitting something

remarkable – adj. very unusual or notable in a way that is admired

rapid – adj. happening or moving very quickly

1 dinosaur   

n.恐龙

参考例句：

• Are you trying to tell me that David was attacked by a dinosaur?你是想要告诉我大卫被一支恐龙所攻击？
• He stared at the faithful miniature of the dinosaur.他凝视著精确的恐龙缩小模型。

2 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

3 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。

4 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》

5 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。

6 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。

7 scenario   

n.剧本，脚本；概要

参考例句：

• But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
• This is a totally different scenario.这是完全不同的剧本。

8 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

9 craters   

n.火山口( crater的名词复数 )；弹坑等

参考例句：

• Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
• The battlefield was full of craters made by exploding shells. 战场上布满弹坑。 来自《现代英汉综合大词典》

10 rebound   

v.弹回；n.弹回，跳回

参考例句：

• The vibrations accompanying the rebound are the earth quake.伴随这种回弹的振动就是地震。
• Our evil example will rebound upon ourselves.我们的坏榜样会回到我们自己头上的。

11 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。

12 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。