Mechanism by which a celestial body generates a magnetic field
This article is about a proposed theory for the source of a planet's magnetic field. For an explanation of the operation of a mechanical dynamo, see Dynamo.
In physics, the dynamo theory proposes a mechanism by which a celestial body such as Earth or a star generates a magnetic field. The dynamo theory describes the process through which a rotating, convecting, and electrically conducting fluid can maintain a magnetic field over astronomical time scales. A dynamo is thought to be the source of the Earth's magnetic field and the magnetic fields of Mercury and the Jovian planets.