sentence: Precession is the wobble of the Earth's axis.
sentences_after: This gyroscopic motion is due to the tidal forces exerted by the sun and the moon on the solid Earth, which has the shape of an oblate spheroid rather than a sphere. The sun and moon contribute roughly equally to this effect.
concept_name: precession
headings: Milankovich cycle The cycles Axial precession
categories: Earth Climate Celestial mechanics