Planets

Planets are "Balanced Bi-Elementals", that is, they are composed of a 50-50 mix of two elements. Each planet is located equidistant from its two parent elements. The Sun is a special case. It is located in the center of the tetrahedron, in the hyperspace core. Also located in the hyperspace core are the four "hyper-planets": Uranus, Neptune, Pluto, and planetary Earth.

Rational for this allocation of Planets

Moon: 50% fire + 50% water = Energetic Emotions. The Moon rules feelings.
Mercury: 50% air + 50% earth = Practical Intellect (i.e., intellect that is "grounded")
Venus: 50% water + 50% earth = Earthy Emotions. Venus rules love and lust.
Mars: 50% fire + 50% air = Energetic Strife (air = sword). Mars rules war.
Jupiter: 50% water + 50% air = Frothy Emotions (joy)
Saturn: 50% fire + 50% earth = Intense Earthiness. Saturn rules inertia and death.

Again, these attributions are not set in stone. Re-arrange them as you see fit.