Kepler's Inner Planets

A 3D model of Johannes Kepler's diagram of the inner planets, first published in his Mysterium Cosmographicum of 1596. At that time six planets were known, and the hypothesis that their orbits were spherical shells nested between the five Platonic solids seemed as reasonable as string theory does now.

This model shows polyhedra corresponding to the inner planets: Mercury, Venus, Earth and Mars. Next outwards would be the tetrahedron followed by Jupiter, then a cube and Saturn, the outermost planet known.

This cube is no longer for sale here, as it turned out not to be of general interest.