[b][url=https://www.youtube.com/watch?v=FDt7V8co1T4]Model of the Earth's magnetic[/url][/b] field according to the self-exciting dynamo hypothesis. In this model, the speed and direction of rotation of the inner core and the outer core can be varied. The speed difference contributes to variations in the strength and orientation of the Earth's magnetic field.[br]See https://www.youtube.com/watch?v=FDt7V8co1T4