The Earth surface may be consider a sphere. The Earth rotates around its axis performing a full turn once a day. The rotation axis of the Earth is perpendicular to the Equatorial Plane which intersects the Earth surface at the Equator, which is a circle.

The Earth revolves around the Sun describing an elliptical orbit on a plane. The eccentricity of the Earth orbit is so small that it can be safely considered a circle, for some purposes.

The plane in which the Earth orbit lies is called the Ecliptic Plane. The rotation axis of the Earth is not perpendicular to the Ecliptic Plane. In fact, the rotation axis of the Earth is inclined around 23° 26’ with respect to the line perpendicular to the Ecliptic Plane. Therefore, the Ecliptic Plane and the Equatorial Plane do not coincide.

The rotation axis of the Earth keeps its direction fixed while the Earth moves along its orbit around the Sun.