AFTER decades of trying, researchers have finally recreated the effect that
is thought to produce the Earth’s magnetic field.
The centre of the Earth is believed to consist of a solid inner core
surrounded by a fluid outer core of molten iron and nickel. The core is too hot
to create a permanent magnetic field like that in a bar magnet. So early this
century, researchers proposed the dynamo theory, which suggests that when liquid
metal such as the material that forms the outer core flows under certain
conditions, it creates a magnetic field. Now scientists based in Germany and…
