Melting poles

We normally think of magnets as solid objects, but the Earth's core is molten and generates a magnetic field from the very flow of the liquid metal of which it is composed. Now, researchers at the École Normale Supérieure (ENS) institutes in Paris and Lyon and the Atomic Energy Commission (CEA) in Saclay have demonstrated that it is possible to create a self-sustaining magnetic field in laboratory experiments even if the fluid flow is highly turbulent. The researchers explain their experimental design offers a realistic simulation of the Earth's dynamo than earlier experiments because the fluid is free to flow in a large tank rather than being channeled using baffles or tubes to mimic the movement of the earth's core. Their results will help scientists better understand magnetic fields in planets and stars.