Hi,
I'll bite. Ok lets say that 250+ million years ago a small planetoid actually struck. The crack could go all round what is now longitude. This could change magnetic north and Earth rotation. this could explain the slight wobble that makes the north star only temporary, (in geological time). This object could also add to the core and water content which would add to overall size of the planet. That would explain why the puzzle could not be put back together again. Well it sounds good anyway.
Cheers,
Chris
