The earth and its axis are not the same, north isn't a fixed point on earth, every year it moves, sometimes as much as 10 metres and has to be reset on gps systems etc. The further the north pole tilts away from the sun the colder the northern hemisphere gets. Several times in the earth's history north has flipped to the other end of the planet completely, reversing the magnetism of the planet. North is also relative, if we all moved further north we wouldn't end up in space, we would end up further north on the planet. north can only be referred to in terms of earth because of its magnetism, orientation and gravity, space doesn't have a direction.