歐洲的科學家們認為他們現(xiàn)在能有把握地描述出是什么導致了地球北磁極的漂移。近年來，地球北磁極已從加拿大移向西伯利亞。

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.

在地球北部的頂端，有一個地方的磁場線垂直指向地球表面。這個地方被稱為北磁極，它隨著時間的推移而漂移。

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世紀初，人們在加拿大北部發(fā)現(xiàn)了北磁極，那時它只是緩慢地向緯度較高的地方漂移。但在20世紀90年代，北磁極離開了原來的地方，迅速穿過北極，向俄羅斯移去。

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.

由英國利茲大學帶領的一支歐洲研究團隊現(xiàn)已把這次劇烈的移動與地球外核液態(tài)鐵流動過程中發(fā)生的具體變化聯(lián)系起來。地球外核是產(chǎn)生和維持地球磁場的 “發(fā)電機”。考慮到北磁極在快速地移動，全球的導航系統(tǒng)剛剛升級?？茖W家表示，北磁極的移動可能還會持續(xù)幾十年。

詞匯

magnetic field lines 磁場線
vertically 豎直地，垂直地
North Magnetic Pole 地球北磁極
wanders 漂離
sighted 被發(fā)現(xiàn)，被看見
drifting 漂移，移動
latitudes 緯度
molten iron 液態(tài)鐵
outer core 外核
dynamo 發(fā)電機
magnetic field 磁場

閱讀理解：請在讀完上文后，回答下列問題。

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.