Catastrophism

Catastrophism is the belief or theory that Earth's geology and biosphere have been shaped primarily or exclusively by recent large-scale catastrophies or cataclysms.

Perhaps the best-known propoment of catastrophism is Immanuel Velikovsky, who wrote a number of books proposing such theories as the planet Venus being a "comet" which was ejected from Jupiter 3,500 years ago and which made a number of catastrophic close passes by Earth and the other planets before settling into its current orbit. Velikovsky uses this to explain the Biblical plagues of Egypt, the Biblical reference to the "Sun standing still" for a day (explained by changes in Earth's rotation), and the sinking of Atlantis. Most scientists consider Velikovsky's theories to be pseudoscience at best, and sheer nonsense at worst.

Other subjects which are often found in catastrophist theories are Noah's flood, "pole shifts" in which Earth's entire outer crust slides over Earth's mantle into a new orientation, and a variety of other fringe beliefs. These are often linked to some form of young-Earth creationism.