Johann Kepler's "Mystery of the Universe" is rightly considered one of the brilliant illustrations in the history of astronomy. In it, Kepler used the five regular Pythagorean solids to refute the major objections to Copernicanism. In this work he demonstrated that vast empty regions lying between the planetary spheres, which were required by Copernicus, were not wasted space. Rather, these gaps perfectly matched, within the limits of observational error, the geometry of the 5 regular Pythagorean solids. This OER explores the role of Kepler's blueprints of the universe in explaining planetary position.