All it takes to simulate the electromagnetic field of our planet is about 15 tons of liquid sodium in a giant spinning globe. Cool!
The deepest we've (we being the Russians) have ever managed to drill down towards the center of the Earth is 40,230 feet (over seven and a half miles). The Kola Superdeep Borehole made it that far after nearly 20 years of drilling, and barely made it a third of the way through the continental crust. So, only another four thousand miles to go to the center.
Yeah, it's not likely we're going to make it down that far anytime soon, which is why the University of Maryland has constructed this gigantic sphere and filled it with superheated liquid sodium. The goal is to spin the outside of the sphere as well as the solid core of the sphere to see if the liquid sodium forms a self-sustaining dynamo, which is how planets (like ours) are thought to generate the magnetic fields which keep us from getting fried by solar radiation. Since we don't have a good way of going and taking a look at what what makes the insides of our Earth tick, experiments like these are really the only way to figure out what's going on way down under our feet.
Check out this attempt at building the core of a planet in a lab in the video below.