【英语时差8,16】为什么磁极会交换方向？

 Every so often, however, that regular motion is interrupted. Think of what happens when you stir that bubbling soup. It takes a few minutes for things to settle down and the regular pattern of bubbling to resume. That’s probably what happens inside earth. Something–maybe nothing more than naturally occurring variations in the process– disrupts the otherwise regular flow of metals in our planet. This shuts off the magnetic field for a while. Eventually, things start bubbling away again and the magnetic field returns. When it comes back on, one end will be north and one end will be south. Whether or not they were aligned¹ that way before the disturbance² is a matter of chance.

1 aligned   

adj.对齐的，均衡的

参考例句：

• Make sure the shelf is aligned with the top of the cupboard.务必使搁架与橱柜顶端对齐。

2 disturbance   

n.动乱，骚动；打扰，干扰；(身心)失调

参考例句：

• He is suffering an emotional disturbance.他的情绪受到了困扰。
• You can work in here without any disturbance.在这儿你可不受任何干扰地工作。