Periodic and cyclical changes in the rotation
of the Earth
that Milutin Milankovich, a Serbian mathematician and physicist, correlated to climatic effects. These cycles influence the amount of solar radiation striking different parts of the Earth at different times of the year, and cause the advance and retreat of the polar ice cap
There are three cycles:
- Changes in the eccentricity of the Earth's orbit, altering the distance between Earth and the Sun at aphelion and perihelion, with a period of about 100000 years.
- Variations in the tilt of the Earth's rotational axis (obliquity of the ecliptic), with a period of42000 years.
- A movement (wobble) in the angle by which the axis of the Earth's rotation is tilted in respect of the orbital plane, altering the seasons at which aphelion and perihelion occur (precession of the equinoxes), with a period of about 21000 years.
These changes in the tilt, orbit and wobble of the Earth correspond to changes in the insolation
) experienced. This in turn is linked to the cycle of glaciation
Climatic changes associated with Milankovich cycles may be recorded in cyclic sedimentation.