Did you even know there was a discipline called paleomagnetics? Probably not.(1) It isn't easy to find a category on this site to put it in, that's for sure.
But a discipline it is and it even has its own controversies, as all science must; namely, the nature of Earth's magnetic field 1.1 billion years ago.
The Earth's magnetic field in two sentences: it wraps around the globe and helps shield us from cosmic rays - lest we all burst into flame or turn into orange rock and say things like, "It's clobberin' time!"