美国有线新闻 CNN 北极地区出现神秘陨石坑

Where would you find the largest known impact crater¹ on Earth? South Africa, Siberia, Antarctica, or Mexico. South Africa's Vredefort crater is the world's largest known impact crater.

以下哪个地方可以找到地球上已知最大的陨石坑？南非、西伯利亚、南极洲还是墨西哥？南非的弗里德堡陨石坑是世界上已知最大的陨石坑。

An impact crater, as the name suggests, is formed when something like an asteroid² crashes into something else like Earth. This more recent phenomenon was not caused by an impact but it is one of 17 craters³ that have mysteriously appeared in the Russian arctic since 2013.

陨石坑，顾名思义，是小行星撞击地球等天体时形成的。但最新出现的陨石坑并非由撞击形成，而是2013年以来神秘出现在俄罗斯北极地区的17个陨石坑之一。

Scientists don't know for sure how this happened. They do know the hole's about 150 deep. Picture three city buses measured end to end and after it was discovered last summer, they flew a drone inside the crater to capture dozens of images from which they built a three-dimensional model. That helped researchers to hypothesis this.

科学家尚不清楚这是如何形成的。他们知道这个洞有150英尺深。这个坑的直径是三辆城市巴士首尾相连的长度，在去年夏天被发现后，人们驾驶一架无人机在陨石坑内拍摄了数十张照片，并根据这些照片建立了一个三维模型。这有助于研究人员进行假设。

Methane⁴ gas somehow accumulates in the permafrost of Siberia. They're not sure whether the gas comes from deep inside the Earth or near its surface but they believe that as the methane builds in a cavity in the ice it forms a mound⁵. And that mound grows until if finally explodes, blasting ice and other debris⁶ and leaving behind the crater.

甲烷气体以某种方式在西伯利亚的永久冻土中积聚。他们不确定这些气体是来自地球深处还是地表附近，但他们相信，甲烷在冰的洞穴中堆积时，就会形成土堆。这个土堆会不断扩大，直到最终爆炸，喷出冰和其他碎片，留下陨石坑。

Scientists are using computer technology to try to predict where this will happen next. These craters appear in sparsely⁷ populated areas. They're usually discovered on accident by reindeer⁸ herders or during helicopter flights of the area.

科学家正在使用计算机技术，试图预测这种情况接下来会发生在哪里。这些陨石坑出现在人口稀少的地区。它们通常由驯鹿牧民偶然发现，或是直升机飞经该地区时意外发现。

1 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。

2 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。

3 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》

4 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

5 mound   

n.土墩，堤，小山；v.筑堤，用土堆防卫

参考例句：

• The explorers climbed a mound to survey the land around them.勘探者爬上土丘去勘测周围的土地。
• The mound can be used as our screen.这个土丘可做我们的掩蔽物。

6 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。

7 sparsely   

adv.稀疏地；稀少地；不足地；贫乏地

参考例句：

• Relative to the size, the city is sparsely populated. 与其面积相比，这个城市的人口是稀少的。 来自《简明英汉词典》
• The ground was sparsely covered with grass. 地面上稀疏地覆盖草丛。 来自《简明英汉词典》

8 reindeer   

n.驯鹿

参考例句：

• The herd of reindeer was being trailed by a pack of wolves.那群驯鹿被一只狼群寻踪追赶上来。
• The life of the Reindeer men was a frontier life.驯鹿时代人的生活是一种边区生活。