Earths magnetic field

Aug 27, 2020
If the earths inner core is growing and, is using up the metallic elements around it forming its outer layer, what happens when / if those elements grow too scarce to enable the outer crystals to form on the cores surface?

Will the 'dynamo' then stop working and what does that mean for the future of our magnetic field ? Or if the core core grows so that it cannot rotate any more as it does now

[very slightly deferentially] to the outer Earth.

Very best wishes,

  • Like
Reactions: Chem721
Jul 27, 2020
Data from orbiting spacecraft at Mars might offer an answer.

The oldest craters on Mars date to 4 bya (or older), and are magnetized from its ancient geodynamo. Craters that are younger than these are not magnetized, indicating that Mars' geodynamo existed for perhaps 500 mys before collapsing. The precise reason for this is debated, but it appears to be related to heat loss. Decreasing heat will ultimately result in the loss of Earth's molten outer core, and failure of the field.

For more information on other notions of the loss of Mars' magnetic field, see :