英语听力精选进阶版 13276

Earth may once have had two moons

Report

This new theory builds on the idea that around four billion years ago the Earth was struck by a Mars-like planet, but instead of the smash producing enough debris¹ for one moon, this paper argues there was enough for two.

This small second moon became stuck in a gravitational tug² of war between the Earth and its much larger sibling³.

After millions of years in this position the new moon was drawn⁴ into a collision at a speed of less than three kilometres per second.

The scientists say this slow paced crash may have caused a build up of material and the formation of highlands on the Moon's far side. 

For decades scientists have been trying to understand why the visible near side of the Moon is covered in craters⁵ while the far side has mountain ranges higher than 3,000 metres.

The researchers hope that Nasa observational missions might prove this new theory within a year.

Matt McGrath, BBC News

1 debris   

n.瓦砾堆，废墟，碎片

参考例句：

• After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
• Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。

2 tug   

v.用力拖(或拉)；苦干；n.拖；苦干；拖船

参考例句：

• We need to tug the car round to the front.我们需要把那辆车拉到前面。
• The tug is towing three barges.那只拖船正拖着三只驳船。

3 sibling   

n.同胞手足(指兄、弟、姐或妹)

参考例句：

• Many of us hate living in the shadows of a more successful sibling.我们很多人都讨厌活在更为成功的手足的阴影下。
• Sibling ravalry has been common in this family.这个家里，兄弟姊妹之间的矛盾很平常。

4 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。

5 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》