Earth Axial Tilt is the term used to describe the extent to which the Earth’s axis is out of true with its orbital plane around the sun. This tilt varies between 24.5 degrees and 22.1 degrees over the course of a 41,000-year cycle. The current tilt is 23.5 degrees.

The Australian astronomer G.F. Dodwell made a study of ancient gnomons erected in many parts of the world and discovered that they did not conform to the theoretical curve. His studies indicate that an unexplained change to the Earth’s axis took place around 2345 BC. He apparently concluded that the data indicated an effect similar to that of a spinning top that has been hit and is regaining equilibrium^(a). Dodwell’s discoveries have been seized upon by creationists as support for a ‘young’ earth.

A number of catastrophists, including Immanuel Velikovsky, have claimed that close encounters or actual impacts with other celestial bodies have caused changes in the Earth’s rotational characteristics. They further contend these changes have occurred within the experience of man, who has conveyed them through myth and legend to us.

There has been considerable speculation that such an encounter may have precipitated tectonic, seismic or tidal effects that led to the destruction of Atlantis.

^(a) http://creationism.org/ackerman/AckermanYoungWorldChap11.htm

See Also: Pole Shift, Charles Hapgood.