ananyo writes: A 3-metre-tall metal sphere full of molten sodium is about to start work modelling the Earth's core. The gigantic dynamo, which has taken researchers 10 years to build, "will generate a self-sustaining electromagnetic field that can be poked, prodded and coaxed for clues about Earth's dynamo, which is generated by the movement of liquid iron in the outer core." Link to Original Source
"The fundamental principle of science, the definition almost, is this: the
sole test of the validity of any idea is experiment."
-- Richard P. Feynman