[edwin hubble]

Pole shifts...
The real topical question in this area involves Earth's inner core.
We know there is a "flipping" of the magnetic poles, about every million years, with no real pattern of periodicity.
Rather than a physical inversion of the core, it now appears that the 2,000 mile diameter solid iron inner core may be a "single crystal". It may invert its polarity without physically turning over.

How? We'll get back to you later on that.
The fascinating things in science are the current mysteries.

[Jeff Gordon]

For those with a sense of humor, you can read all about the pole shift.

And you find find more details behind this deranged thinking

[Nebullis]

I can manage a polarity transition. It's those radical surface shifts I'm really worried about. I think I'll build a safe room so I can panic there.