A new model of the Earth, 20 years in the making, describes a dynamic three-dimensional puzzle of planetary proportions. Created by University of Wisconsin-Madison geophysicist Chuck DeMets and longtime collaborators Richard Gordon of Rice University and Donald Argus of NASA's Jet Propulsion Laboratory, the model offers a precise description of the relative movements of 25 interlocking tectonic plates that account for 97 percent of the Earth's surface. "This model can be used to predict the movement of one plate relative to any other plate on the Earth's surface," explains DeMets. "Plate tectonics describes almost everything about how the Earth's surface...