2. Passive levitation of permanent magnets: diamagnetic levitation

On a practical level, if we consider the experiment of suspending a permanent magnet in a magnetic field created by a second magnet, we'll soon realize that this is impossible. On a theoretical level, Earnshaw in 1842 demonstrated that it is not possible to obtain a stable equilibrium point with a configuration made up of elements interacting with forces that are inversely proportional to the square of the distance. The magnetic forces produced by magnets have just this property. He...