Ecliptic Zodiac Plane

sci:astro:ecliptic_zodiac_plane

The planets keep to the narrow band of the zodiac because the solar system is nearly flat: the Sun, Moon, and planets all ride close to one plane, the ecliptic, and the zodiac is that plane drawn against the far stars. The circle of beasts the Babylonians marked is the edge of our own planetary disc, seen from inside.