Sublunary Sphere

Definition

The sublunary sphere is the region inside the Moon's orbit — in Obert's account, the changeable world where things are born, grow, decline, and die. It is the home of the four ancient elements, which he places in concentric rings beneath the Moon. Fire lies on the outside, then air and water within it, and earth, as the heaviest, settled at the very center. In the Aristotelian-Ptolemaic model everything above the Moon moves in eternal, orderly, predictable fashion; everything below it is the realm of generation and corruption.

In Tradition

Obert sets out the standard pre-modern partition of the cosmos. Above the Moon lie the planetary spheres, the fixed stars, and the Primum Mobile, a realm of regular and predictable motion. Below the Moon lie the Earth and its four-element atmosphere, where things come to be and pass away. What drives change down here, on this view, is the way the elements act on and turn into one another. The planets do not belong to this lower realm — they act upon it, by what Obert calls elemental affinity, the heavens working their effect on the changeable region beneath them.

In Practice

Let this frame how you picture astrological influence in the traditional cosmos. The sublunary sphere is the world being acted upon — the earthly, four-element realm where coming-to-be and passing-away play out. The planets above send their effect down into it by elemental affinity. Keep it distinct from the encompassing celestial medium, the ambient (to periechon), which is the transmitting side of the relationship: the ambient carries the influence, the sublunary sphere receives it. Holding the two apart clarifies the old model, in which an orderly heaven shapes a changeable earth across the boundary of the Moon's orbit.

Historical Origin

The cosmology is set out by Charles Obert in Introduction to Traditional Natal Astrology (2015, Chapter 4, "Worldview," printed p. 24). There the sublunary sphere within the Moon's orbit is described as the changeable realm of the four elements, ringed with the lightest element outermost and the heaviest at the center. The planets act on it by elemental affinity (Chapter 11), the model inheriting Aristotle's partition of the cosmos.

Etymology

Origin: Latin. Meaning: the sphere below the Moon.

Further Reading

• Charles Obert, Introduction to Traditional Natal Astrology
• Ptolemy, Tetrabiblos