Teorien om at jorden er hul

Astronomen Edmond Halley (1656–1742) med en prinsippskisse over sin teori fra 1692 om en hul jord med flere skall utenpå hverandre.

Teorien om at jorden er hul er en teori som hevder at jorden er hul og kanskje beboelig på innsiden. Denne antagelsen er motbevist ved geologiske undersøkelser og moderne kunnskap om planetenes tilblivelse. Teorien er i dag utdatert som reell, men finnes fremdeles innenfor begrepet pseudovitenskap. Ideen har også et visst fotfeste innenfor eventyrfortellinger og science fiction.

Dersom en hadde lyktes i å bebo jordskallets innside, ville en fått en overraskelse – vektløshet. På innsiden av et skall vil gravitasjonskreftene fra skallet utbalansere hverandre og netto gravitasjon blir null.

Eksterne lenker

• Umberto Eco (21. juli 2006). «Outlandish theories: Kings of the (hollow) world». International Herald Tribune. Arkivert fra originalen 5. august 2006.  Review of Paul Collins' book Banvard's Folly, which includes a chapter on Symmes.
• Griffin, Duane A.; Hollow and Habitable Within: Symmes's Theory of Earth's Internal Structure and Polar Geography – a scholarly article on Symmes's theory
• At the Earth's Core, by Edgar Rice Burroughs
• The Cellular Cosmogony, by Koresh: full text of Cyrus Teed's book about the inside-out Earth at www.sacred-texts.com
• The Phantom of the Poles, by William Reed: full text at www.sacred-texts.com
• Hollow Earths: page illustrating several hollow-Earth proposals with diagrams
• Stephen Wagner, Nazis and the Hollow Earth, Paranormal.About.com (11 January 1999): (thinly sourced) discussion of rumors about the Nazis and hollow Earth ideas.
• Koreshan State Historic Site, official web page.
• Unofficial Koreshan State Historic Site, unofficial web page.
• American Communal Utopias and The Koreshan Unity: A Bibliography Brief overview and great bibliography of works, if slightly dated.
• Turning the Universe Inside-Out: Ulysses Grant Morrow's Naples Experiment Examination of the Naples Experiment, and why it failed, but also covers the major hollow Earth theories and Koreshan beliefs.
• The Smoky God, by Willis George Emerson. Complete novel
• Voyage to our Hollow Earth, Journey to the North Pole and Beyond – 24 day Trip, June 26 2006 – July 19 2006. Expedition aboard the nuclear-powered Russian icebreaker Yamal
• The Hollow Earth – from The UnMuseum
• Hollow Earth Insider, "a dedicated worldwide group of Insiders researching, not only the Hollow Earth/Subterranean Mysteries, but also reports on the UFO/Alien connection and other mysteries, the New World Order and other conspiracies"
• The Expanding Hollow Earth Theory – a book by proponents of a hollow-Earth theory.
• The Hollow Earth Theory, "A band inspired by the theory"
• List of Some Hollow Earth books in Print at amazon.com
• Phoenix Science Foundation, organization supporting an expedition