You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: THE EARTH 
Clue: As Earth wobbles slowly on its axis, this moves in a "Chandler Circle" with a diameter of about 1 to 70 feet
the north pole