Spinning them slowly has not created the so-called dynamo effect, thought to be responsible for creating magnetic fields.

旋转这两个球体并不能制造所谓的发电机效应，这种效应被认为能制造磁场。

And the motion of that molten iron, along with some complicated physics, generates a magnetic field through something called the dynamo effect.

铁水的运动， 连同一些复杂的物理现象，通过一种叫做发电机效应的东西产生了磁场。