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 aligned that way before the disturbance is a matter of chance.

【生词注释】
interrupt v.打断
settle down 平静下来
resume v. 重新开始
variation n.变化
align vi.排行
disturbance n.扰乱

【参考译文】
尽管如此，常规的运动不时被打断。想想当你捅破热汤中的气泡时，发生的状况。得需要几分钟热汤才能平静袭来，正常的冒泡形式才会重新开始。那也可能是地球内部的模式。有些物质——很可能是是自然变化过程中的物质——打断了地球内部金属的正常流动。这导致磁场失效了一段时间。最终，冒泡过程重新开始，磁场重新出现。当磁场重现出现时，一端是北极，另一段是南极。在磁场被阻断钱它们是否按照那种方式派别完全是随机的。