Eli5: what does it mean when someone talks about the poles reversing?

Question

I hear people talking about the earths magnetic poles reversing but how exactly could/would that happen?

In: 27

Answer 1

The earth has a big magnetic forcefield around it, this forcefield can decay because our planet has lots of magnetic liquid metals around the core, we wobble and spin so it moves around.

If it decays enough, north and south can flip entirely, exposing us to all sorts of nasty space energy