Well the earth does have this little wobble called procession; I personally think because of this the Poles simply move around a bit, which throws everything out of whack. For instance the Antarctic has fruit trees buried deep in the ice that still have fruit on them. And then there is that 600 year old map that shows the exact outline of the Antarctic with out any Ice, describes rivers and bays and so forth, problem is know one new about any of this until the last 20 years or so when satellites were able to take radar images of the actual continent sans the Ice. So how did those old sailors know all about this place only a few hundred years ago?