Figure 8-14:

The Kuiper Belt and Oort Cloud (a) The classical Kuiper belt of comets spreads from Neptune out to 50 AU from the Sun. Most of the estimated 200 million belt comets are believed to orbit in or near the plane of the ecliptic. The spherical Oort cloud extends from beyond the Kuiper belt. (b) Orbits of bodies in the Kuiper belt.

(b: NASA and A. Field/Space Telescope Science Institute)