As I have noted elsewhere, I have no special knowledge of Scientology beyond court records and other publicly-available materials. Scientology claimed in the case of Religious Technology Center v. F.A.C.T.Net, Inc., et al. (1995) that “the discussion of the -- of the volcanoes, the explosions, the Galactic confederation 75 million years ago, and a gentleman by the name Xemu there. Those are not trade secrets.” The following discussion is based on the public record.
Theosophy: The universe is inhabited by countless forms of intelligent life living on linked sets of seven worlds existing in parallel universes called “etheric planes.”
Scientology: The universe is controlled by a Galactic Confederation of 76 linked worlds.
Theosophy: Extraterrestrial visitors from Venus came to the ancient earth more than 16 million years ago.
Scientology: Extraterrestrial visitors from the Confederation came to the ancient earth more than 75 million years ago.
Theosophy: The Venusians traveled to earth through mind projection (according to W. Scott-Elliot), inhabiting the bodies of the root race of Lemuria, or through an armada of space ships (according to A. E. Powell).
Scientology: The extraterrestrials came to earth in an armada of space ships shaped like DC-8 airplanes.
Theosophy: Due to an “increase in fecundity” (Powell), the aliens had to come to earth in large numbers to spread out their population.
Scientology: Due to an overpopulation of 178 billion individuals per planet, the aliens had to come to earth to relieve overpopulation.
Theosophy: The Venusians projected their minds into primitive earth bodies and took over the Lemurian race. These Venusians became the leaders of the Lemurians and taught them culture and spirituality.
Scientology: The souls (“thetans”) of the aliens were distributed across the world when their leader, Xenu, blew up the aliens immigrants with hydrogen bombs. These thetans attached themselves to modern human souls, imparting false teachings about culture and religion.
Theosophy: The Venusians were responsible for creating or inspiring ancient works of architecture, especially the stone monuments of the Pacific.
Scientology: The aliens constructed buildings in the Pyrenees, Canary Islands, and elsewhere.
Theosophy: The aliens’ reign ended when Atlantis and Lemuria were destroyed by volcanic eruptions. Memories of this period form the basis of all human myth and religion.
Scientology: The aliens’ physical bodies are destroyed when Xenu detonates hydrogen bombs in the volcanoes where they are imprisoned. All human myth and religion are inculcated into the aliens’ now-disembodied souls, which they will transfer to human beings.