The book postulates that around the 15th century BC, the planet Venus was ejected from Jupiter as a comet or comet-like object and passed near Earth (an actual collision is not mentioned).

The object allegedly changed Earth's orbit and axis, causing innumerable catastrophes that are mentioned in early mythologies and religions from around the world.

The book has been heavily criticized as a work of pseudoscience and catastrophism, and many of its claims are completely rejected by the established scientific community as they are not supported by any available evidence.

[3] Despite this popularity, overwhelming rejection of its thesis by the scientific community forced Macmillan to stop publishing it and to transfer the book to Doubleday within two months.

In doing so it changed Earth's orbit and axial inclination, causing innumerable catastrophes which were identified in early mythologies and religious traditions from human civilizations around the world.

Then, in the 8th and 7th centuries BCE, Mars (itself displaced by Venus) made close approaches to the Earth; this incident caused a new round of disturbances and disasters.

[13] Velikovsky tried to protect himself from criticism of his proposed celestial mechanics by removing the original Appendix on the subject from Worlds in Collision, hoping that the merit of his ideas would be evaluated on the basis of his comparative mythology and use of literary sources alone.

This strategy did not protect him: the Appendix was an expanded version of the Cosmos Without Gravitation monograph, which he had already distributed to Shapley and others in the late 1940s — and they had regarded the physics within it as egregiously in error.

The essential characteristics of the Jovian radio emission — that it is nonthermal, polarized, intermittent radiation, connected with the vast belts of charged particles which surround Jupiter, trapped by its strong magnetic field — are nowhere predicted by Velikovsky.

Tim Callahan, religion editor of Skeptic, presses the case further in claiming that the composition of the atmosphere of Venus is a complete disproof of Worlds in Collision.

"[18] Astronomer Philip Plait has pointed out that Velikovsky's hypothesis is also falsified by the presence of the Moon with its nearly circular orbit, for which the length of the month has not changed sensibly in the more than 2,000 years the Hebrew calendar has been in use.

His criticism is published in Scientists Confront Velikovsky (Ithaca, New York, 1977), edited by Donald Goldsmith, and presented in a revised and corrected version in his book Broca's Brain: Reflections on the Romance of Science and is much longer than that given in the talk.

"[21] In November 1974, at the Biennial Meeting of the Philosophy of Science Association held at the University of Notre Dame, Michael W. Friedlander, professor of physics at Washington University in St. Louis, confronted Velikovsky in the symposium "Velikovsky and the Politics of Science" with examples of his "substandard scholarship" involving the "distortion of the published scientific literature in quotations that he used to support his theses".

This failure to recognize the power of comets and asteroids means that it is reasonable to go back to Velikovsky and delete all the physically impossible text about Venus and Mars passing close to the earth.

[32][33] So far, the only piece of the geologic evidence which has shown to have a catastrophic origin is a "raised beach" containing coral-bearing conglomerates found at an elevation of 1,200 feet above sea level within the Hawaiian Islands.

The sediments, which were misidentified as a "raise beach", are now attributed to megatsunamis generated by massive landslides created by the periodic collapse of the sides of the islands.