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Contents of 10.3 How does outer-core convection generate the magnetic field?

10.3 How does outer-core convection generate the magnetic field?

• The magnetic field changes with time both in strength and orientation.
• Magnetic minerals in rocks preserve a record of the prior magnetic field(s).
• There are records of magnetic reversal in the past.
• The current field is in a "normal" orientation.
• When the magnetic pole we call "North" is at the southern pole, this is termed "reversed."
• Since the magnetic field shields life from cosmic rays, and the field "dims" before it changes, reversal events are often a time of massive biologic adjustment.