Here's why:
* The Ecliptic is the Plane of Earth's Orbit: The Earth orbits the Sun in a plane, and this plane is called the ecliptic plane. From our perspective on Earth, the Sun appears to move along a path in the sky that follows this plane.
* Stars as a Background: The stars are much further away than the Sun, so they appear relatively stationary. As the Earth orbits the Sun, we see the Sun against the backdrop of these stars.
* Apparent Path: The Sun's apparent path through the background stars defines the ecliptic.
In Summary: The ecliptic is the apparent path of the Sun, and therefore the planets (which orbit the Sun in a similar plane), as seen from Earth against the backdrop of the fixed stars.
