While all planets in our solar system orbit the Sun in roughly the same plane, called the ecliptic plane, they are not perfectly aligned.

Here's why:

* The ecliptic plane is defined by the Earth's orbit. Every planet has a slightly different orbital plane due to gravitational interactions during formation.

* The inclination of a planet's orbit is the angle between its orbital plane and the ecliptic plane.

Planets with the largest inclinations to the ecliptic plane:

* Mercury: 7 degrees

* Pluto: 17 degrees (Pluto is now classified as a dwarf planet)

Other planets have smaller inclinations:

* Venus: 3.4 degrees

* Mars: 1.85 degrees

* Jupiter: 1.3 degrees

* Saturn: 2.5 degrees

* Uranus: 0.77 degrees

* Neptune: 1.77 degrees

While the inclinations are small, they are significant enough to cause the planets to appear to "wander" slightly above and below the ecliptic plane as seen from Earth.