The complex interaction that gives our planet its magnetic field results in a field that is likewise complex. This computer-generated graphic is derived from a computer model created by Gary Glatzmaier of UC Santa Cruz and Paul Roberts of UCLA. To fashion their model, Glatzmaier and Roberts made use of dozens of equations that describe the dynamics of Earth's interior.

As with this snapshot from the computer model, the Earth's magnetic field is not uniform. The intensity and direction of the field changes not only from one location to another, but over time as well.