The ecliptic plane is an imaginary flat surface that represents the path the Earth takes as it orbits the Sun. This plane is tilted at an angle of about 23.5 degrees relative to the celestial equator, which is the projection of the Earth's equator into space. In astronomy, the ecliptic plane is important for understanding the positions of the planets and other celestial bodies in our solar system. It serves as a reference point for measuring the orbits of these objects and helps astronomers predict their movements over time.