Figure 184.108.40.206. The orbit of the Earth is shown here in a simplified perspective drawing. The horizontal gray plane contains the Earth's orbital plance at an arbitary date and comprises the reference plane. Click for a more detailed view. Abbreviations are: prec., general precession (wobble) of the Earth's rotational axis; obliq., obliquity of the Earth's axis (tilt); I, inclination of the plane of the Earth's orbit relative to the reference frame; P, point of perihelion.