What Is the Ecliptic, and Why Is It Tilted With Respect to the Celestial Equator?

The ecliptic is the course the sun is observed to take from the point of a view of Earth as it appears to revolve around Earth in a line that is inclined with respect to the rotation axis at 23.50, according to Georgia State University’s Hyperphysics. The ecliptic intersects the celestial equatorial along the path between the equinoxes.

The ecliptic is tilted because the rotation of Earth on its axis is tilted relative to the plane of its orbit around the Sun by 23.5 degrees. Hyperphysics states that observations indicate that other planets revolve around the Sun along essentially the same plane. Also, most other orbiting objects lie on the ecliptic plane. The notion implies that the solar system was formed from a process that created a disk of material based on which the sun and the planets came to be. The 23.5 degree angle of inclination of Earth’s rotation on its own axis results in seasonal alterations in the intensity of sunlight received at the surface.

According to NASA’s Goddard Space Flight Center, Pluto, which orbits the sun from a distance that is 39.5 degrees that of Earth, moves in an orbital plane tilted by 170 degrees. Some recent additions to the Kuiper Belt group, to which Pluto belongs, have a tilt angle of 280 degrees.