The discussion centers on why the planets in the solar system predominantly lie in a flat plane, known as the ecliptic. This alignment is attributed to the initial cloud of gas and dust that formed the solar system, which flattened due to gravitational forces and rotation. While most major planets have orbits close to this plane, some, like Pluto, have significantly inclined orbits. Additionally, the Oort cloud, which contains many comets, is roughly spherical due to gravitational interactions, although its innermost part may also exhibit a planar structure. Overall, the formation dynamics of the solar system explain the general flatness of planetary orbits.