Source of Earth’s Magnetic Field
A new study proposed that the ‘basal magma ocean’ of the earth, and not its core, is responsible for the earth’s magnetic field.
The dynamo theory gives the mechanism by which stars and planets generate magnetic fields around them. It postulates that an electrically conductive fluid that is rotating and convecting in the interior of the star/ planet, gives rise to the magnetic field which is sustained over long periods of time. This is also applicable to the earth.
Basal Magma Ocean
The earth is composed of an inner core, an outer core, a lower mantle, an upper mantle and a crust. The term ‘basal magma ocean’ is used to refer to the bottom 1/3rd of the mantle that had existed in a molten condition during the first half of earth’s 4.5 billion year existence.
Silicate is a poor conductor of electricity and it composes the mantle portion of the earth. However, the researchers propose that liquid silicate might be more electrically conductive. They used quantum mechanical computation to determine conductivity of the silicates in the basal magma ocean.