Now, perhaps what may be surprising, to you because we live in
this period of relative stasis where the Earth's magnetic field,
has been undergoing very little changes on the scale of human life time, is that.
The earth magnetic field can sometimes reverse.
And what I mean by that, is that the south magnetic pole in the southern hemisphere,
becomes the North magnetic pole in the Southern hemisphere and
thus essentially compasses would, would point the other way.
So where is now we've built compasses to point towards,
the geographic north, after a reversal,
it would be pointing towards the geographic south, the north magnetic pole.