Magnetic Records

Came across a couple interesting stories last week about researchers using the logs of seventeenth century vessels to measure the historical strength and location of the magnetic pole. They concluded that the magnetic field is weakening, a finding that corroborates other research into the magnetic field.

Previous magnetic pole reversals were preceded by a weakening magnetic field, and this weakening fits the pattern. The field is still quite strong though, so researchers think a pole reversal could be several thousand years in the future if the weakening continues apace.