Ptolemy assigned the following order to the planetary spheres, beginning with the innermost:

These days the planetary spheres of influence overlapped in the Belt with uneasy tolerance.

The seven planetary spheres or heavens were for the ancients the highest regions of the created universe.

When scholars applied Ptolemy's epicycles, they presumed that each planetary sphere was exactly thick enough to accommodate them.

In more detailed models the seven planetary spheres contained other secondary spheres within them.

The ancient astronomy taught that above the seven planetary spheres was an eighth, the sphere of the fixed stars.

They then descend, one by one, through the planetary spheres.

Anderson must also have been aware of the doctrine that the seven planetary spheres, with their different tones, produce a celestial music.

The dot representing the hurtling iceberg still moved very fast, though, and the planetary sphere had to shrink in compensation.

In the natural music of our orbiting planetary sphere, they are pure dissonance.