欧洲的科学家们认为他们现在能有把握地描述出是什么导致了地球北磁极的漂移。近年来，地球北磁极已从加拿大移向西伯利亚。

At the top of the world, there is a place where magnetic field lines point vertically into the Earth's surface. It's called the North Magnetic Pole and it wanders over time.

在地球北部的顶端，有一个地方的磁场线垂直指向地球表面。这个地方被称为北磁极，它随着时间的推移而漂移。

Back in the early nineteenth century, it was sighted in the north of Canada and was drifting only slowly to slightly higher latitudes. But then in the 1990s, it took off, racing across the Arctic towards Russia.

早在19世纪初，人们在加拿大北部发现了北磁极，那时它只是缓慢地向纬度较高的地方漂移。但在20世纪90年代，北磁极离开了原来的地方，迅速穿过北极，向俄罗斯移去。

A European team, led from Leeds University, has now tied this dramatic movement to specific changes in the flow of molten iron in the Earth's outer core – the dynamo that creates and sustains its magnetic field. World navigation systems have just been updated to account for the pole’s rapid movement, which the scientists say, could continue for decades yet.

由英国利兹大学带领的一支欧洲研究团队现已把这次剧烈的移动与地球外核液态铁流动过程中发生的具体变化联系起来。地球外核是产生和维持地球磁场的 “发电机”。考虑到北磁极在快速地移动，全球的导航系统刚刚升级。科学家表示，北磁极的移动可能还会持续几十年。

词汇

magnetic field lines 磁场线
vertically 竖直地，垂直地
North Magnetic Pole 地球北磁极
wanders 漂离
sighted 被发现，被看见
drifting 漂移，移动
latitudes 纬度
molten iron 液态铁
outer core 外核
dynamo 发电机
magnetic field 磁场

阅读理解：请在读完上文后，回答下列问题。

1. True or false? The Earth’s North Magnetic Pole stays in the same place.

2. What is the North Magnetic Pole?

3. What was sighted in the early nineteenth century?

4. How long could the pole’s rapid movement last, according to scientists?

答案  

1. True or false? The Earth’s North Magnetic Pole stays in one place.
False. The Earth’s North Magnetic Pole wanders over time.

2. What is the North Magnetic Pole?
It is a place where magnetic field lines point vertically into the Earth's surface at the top of the world.

3. What was sighted in the early nineteenth century?
The North Magnetic Pole was sighted in the north of Canada and it was drifting only slowly to slightly higher latitudes.

4. How long could the pole’s rapid movement last, according to scientists?
Scientists say the pole’s rapid movement could continue for decades yet.