Hollow Earth

The Hollow Earth hypothesis says that the planet Earth is either wholly hollow or otherwise contains a substantial interior space. The hypothesis has long been contradicted by overwhelming observational evidence, as well as by the modern understanding of planet formation. The scientific community has dismissed the notion since at least the late 18th century.

The concept of a hollow Earth still recurs in folklore and as the premise for subterranean fiction, a subgenre of adventure fiction. It is also featured in some present-day pseudoscientific and conspiracy theories.

Hypotheses

Edmond Halley's hypothesis.

Leonhard Euler's purported hollow-Earth thought-experiment, featuring openings at the poles, with an internal star.

Conventional hollow Earths

Early history

In ancient times, the idea of subterranean realms seemed arguable, and became intertwined with the concept of "places" such as the Greek Hades, the Nordic svartalfheim, the Christian Hell, and the Jewish Sheol (with details describing inner Earth in Kabalistic literature, such as the Zohar and Hesed L'Avraham).

Edmond Halley in 1692^[1] put forth the idea of Earth consisting of a hollow shell about 800 km (500 miles) thick, two inner concentric shells and an innermost core, about the diameters of the planets Venus, Mars, and Mercury. Atmospheres separate these shells, and each shell has its own magnetic poles. The spheres rotate at different speeds. Halley proposed this scheme in order to explain anomalous compass readings. He envisaged the atmosphere inside as luminous (and possibly inhabited) and speculated that escaping gas caused the Aurora Borealis.^[2]

De Camp and Ley have claimed (in their Lands Beyond) that Leonhard Euler also proposed a hollow-Earth idea, getting rid of multiple shells and postulating an interior sun 1000 km (600 miles) across to provide light to advanced inner-Earth civilization (but they provide no references). However in his Letters to a German princess^[3] Euler describes a thought experiment involving a patently solid Earth.

De Camp and Ley also claim that Sir John Leslie expanded on Euler's idea, suggesting two central suns named Pluto and Proserpine (this was unrelated to the dwarf planet Pluto, which was discovered and named some time later). Leslie did propose a hollow Earth in his 1829 Elements of Natural Philosophy (pp. 449–453), but does not mention interior suns.

19th century

In 1818, John Cleves Symmes, Jr. suggested that the Earth consisted of a hollow shell about 1300 km (800 miles) thick, with openings about 2300 km (1400 miles) across at both poles with 4 inner shells each open at the poles. Symmes became the most famous of the early Hollow Earth proponents. He proposed making an expedition to the North Pole hole, thanks to efforts of one of his followers, James McBride. United States president John Quincy Adams indicated he would approve of this but he left office before this could occur. The new President of the United States, Andrew Jackson, halted the attempt.

Jeremiah Reynolds also delivered lectures on the "Hollow Earth" and argued for an expedition. Reynolds went on an expedition to Antarctica himself but missed joining the Great U.S. Exploring Expedition of 1838–1842, even though that venture was a result of his agitation.

Though Symmes himself never wrote a book about his ideas, several authors published works discussing his ideas. McBride wrote Symmes' Theory of Concentric Spheres in 1826. It appears that Reynolds has an article that appeared as a separate booklet in 1827: Remarks of Symmes' Theory Which Appeared in the American Quarterly Review. In 1868, a professor W.F. Lyons published The Hollow Globe which put forth a Symmes-like Hollow Earth hypothesis, but didn't mention Symmes. Symmes's son Americus then published The Symmes' Theory of Concentric Spheres in 1878 to set the record straight.

20th century

The Nazi era Thule Society reported much about Tibetan myths of openings into the Earth. There is even a theory that Hitler ordered a research journey for such an opening in Antarctica, based on a speech of Admiral Dönitz in front of a German submarine in 1944, when he claimed "The German submarine fleet is proud of having built an invisible fortification for the Führer, anywhere in the world." During the Nuremberg Trials, Dönitz spoke of "an invisible fortification, in midst of the eternal ice."^[4]

An early twentieth-century proponent of hollow Earth, William Reed, wrote Phantom of the Poles in 1906. He supported the idea of a hollow Earth, but without interior shells or inner sun.

Marshall Gardner wrote A Journey to the Earth's Interior in 1913 and an expanded edition in 1920. He placed an interior sun in the hollow Earth. He even built a working model of the hollow Earth and patented it (#1096102). Gardner made no mention of Reed, but did take Symmes to task for his ideas. In the same time Vladimir Obruchev wrote a fiction novel Plutonia, where the hollow Earth's interior possessed one inner (central) sun and was inhabited by prehistoric species. The interior was connected with the surface by a hole in the Arctic.

Other writers have proposed that "ascended masters" of esoteric wisdom inhabit subterranean caverns or a hollow Earth. Antarctica, the North Pole, Tibet, Peru, and Mount Shasta in California, USA, have all had their advocates as the locations of entrances to a subterranean realm referred to as Agartha, with some even advancing the hypothesis that UFOs have their homeland in these places.

A book allegedly by a "Dr. Raymond Bernard" which appeared in 1964, The Hollow Earth, exemplifies this idea. The book rehashes Reed and Gardner's ideas and ignores Symmes. Bernard also adds his own ideas: the Ring Nebula proves the existence of hollow worlds, as well as speculation on the fate of Atlantis and the origin of flying saucers. "Bernard" argued that the inhabitants of Atlantis took refuge in the Earth's interior before the city was destroyed in great calamity.^[5] It was Atlanteans who piloted the flying machines known in ancient India as vimanas and in the modern world as flying saucers.^[5] After the US bombings of Hiroshima and Nagasaki, Bernard claimed, the Atlanteans became concerned that radioactive air might flow into the world's interior, and so some emerged in their flying saucers in an act of self-defense.^[5] An article by Martin Gardner revealed that Dr.Walter Siegmeister used the pseudonym `Bernard', but not until the publishing of Walter Kafton-Minkel's Subterranean Worlds: 100,000 years of dragons, dwarves, the dead, lost races & UFOs from inside the Earth, in 1989, did the full story of Bernard/Siegmeister become well known.

The pages of the science fiction pulp magazine Amazing Stories promoted one such idea from 1945 to 1949 as "the Shaver Mystery". The magazine's editor, Ray Palmer, ran a series of stories by Richard Sharpe Shaver supposedly claimed as factual, though presented in the context of fiction. Shaver claimed that a superior pre-historic race had built a honeycomb of caves in the Earth, and that their degenerate descendants, known as "Dero", live there still, using the fantastic machines abandoned by the ancient races to torment those of us living on the surface. As one characteristic of this torment, Shaver described "voices" that purportedly came from no explainable source. Thousands of readers wrote to affirm that they, too, had heard the fiendish voices from inside the Earth.

Fantastic stories (supposedly believed as factual within fringe circles) have also circulated that Adolf Hitler and some of his followers escaped to hollow lands within the Earth after World War II via an entrance in Antarctica. (See also Hitler's supposed adherence to concave hollow-Earth ideas, below.)

Some writers have proposed building megastructures that have some similarities to a hollow Earth – see Dyson sphere, Globus Cassus.

Concave hollow Earths

An example of a concave hollow Earth. Humans live on the interior, with the universe in the center.

Instead of saying that humans live on the outside surface of a hollow planet, sometimes called a "convex" hollow-Earth hypothesis, some have claimed that our universe itself lies in the interior of a hollow world, calling this a "concave" hollow-Earth hypothesis. The surface of the Earth, according to such a view, might resemble the interior shell of a Dyson sphere.

Purportedly verifiable hypotheses of a "concave hollow Earth" need to be distinguished from a thought experiment which defines a coordinate transformation such that the interior of the Earth becomes "exterior" and the exterior becomes "interior". (For example, in spherical coordinates, let radius r go to R²/r where R is the Earth's radius.) The transformation entails corresponding changes to the forms of physical laws. This is not a hypothesis but an illustration of the fact that any description of the physical world can be equivalently expressed in more than one way.^[6]

Cyrus Teed, an eccentric doctor from upstate New York, proposed such a concave hollow Earth in 1869, calling his scheme "Cellular Cosmogony". Teed founded a cult called the Koreshan Unity based on this notion, which he called Koreshanity. The main colony survives as a preserved Florida state historic site, at Estero, Florida, but all of Teed's followers have now died. Teed's followers claimed to have experimentally verified the concavity of the Earth's curvature, through surveys of the Florida coastline making use of "rectilineator" equipment.

Several twentieth-century German writers, including Peter Bender, Johannes Lang, Karl Neupert, and Fritz Braun, published works advocating the hollow Earth hypothesis, or Hohlweltlehre. It has even been reported, although apparently without historical documentation, that Adolf Hitler was influenced by concave hollow-Earth ideas and sent an expedition in an unsuccessful attempt to spy on the British fleet by aiming infrared cameras up into the sky^[7] (Wagner, 1999).^[8]

The Egyptian mathematician Mostafa Abdelkader authored several scholarly papers working out a detailed mapping of the concave Earth model. See M. Abdelkader, "A Geocosmos: Mapping Outer Space Into a Hollow Earth," 6 Speculations in Science & Technology 81–89 (1983). Abstracts of two of Abdelkader's papers also appeared in Notices of the American Mathematical Society, (Oct. 1981 and Feb. 1982).

In one chapter of his book On the Wild Side (1992), Martin Gardner discusses the hollow Earth model articulated by Abdelkader. According to Gardner, this hypothesis posits that light rays travel in circular paths, and slow as they approach the center of the spherical star-filled cavern. No energy can reach the center of the cavern, which corresponds to no point a finite distance away from Earth in the widely accepted scientific cosmology. A drill, Gardner says, would lengthen as it traveled away from the cavern and eventually pass through the "point at infinity" corresponding to the center of the Earth in the widely accepted scientific cosmology. Supposedly no experiment can distinguish between the two cosmologies.

Gardner notes that "most mathematicians believe that an inside-out universe, with properly adjusted physical laws, is empirically irrefutable". Gardner rejects the concave hollow Earth hypothesis on the basis of Occam's Razor.

Contrary evidence

Gravity

The best scientific argument against that of a hollow Earth or any hollow planet is gravity. Massive objects tend to clump together gravitationally, creating non-hollow spherical objects we call stars and planets. The solid sphere is the best way in which to minimize the gravitational potential energy of a physical object; having hollowness is unfavorable in the energetic sense. In addition, ordinary matter is not strong enough to support a hollow shape of planetary size against the force of gravity; a planet-sized hollow shell with the known, observed thickness of the Earth's crust, would not be able to achieve hydrostatic equilibrium with its own mass and would collapse.

Someone on the inside of a hollow Earth would not experience a significant outward pull and could not easily stand on the inner surface; rather, the theory of gravity implies that a person on the inside would be nearly weightless. This was first shown by Newton, whose shell theorem mathematically predicts a gravitational force (from the shell) of zero everywhere inside a spherically symmetric hollow shell of matter, regardless of the shell's thickness. A tiny gravitational force would arise from the fact that the Earth does not have a perfectly symmetrical spherical shape, as well as forces from other bodies such as the Moon. The centrifugal force from the Earth's rotation would pull a person (on the inner surface) outwards if the person was traveling at the same velocity as the Earth's interior and was in contact with the ground on the interior, but even the maximum centrifugal force at the equator is only 1/300 of ordinary Earth gravity.

The mass of the planet also indicates that the hollow Earth hypothesis is unfeasible. Should the Earth be largely hollow, its mass would be much lower and thus its gravity on the outer surface would be much lower than it is.

Seismic information

Although not visually observable, the core of the Earth is observable via vibrations (primarily from earthquakes) passing from one side of the planet to the other. Using this method, geologists have been able to postulate the structure of mantle, outer core, and inner core known today. A hollow earth would behave entirely differently in terms of seismic observations.

Visual evidence

The deepest hole drilled to date is the SG-3 borehole which is 12.3 km (7.6 miles)^[9] deep, part of the Soviet Kola Superdeep Borehole project; thus, visual knowledge of the Earth's structure extends that far.

In fiction

A map of the Interior World, from The Goddess of Atvatabar (1892).

The idea of a hollow Earth is a very common element of fiction, appearing as early as Ludvig Holberg's 1741 novel Nicolai Klimii iter subterraneum (Niels Klim's Underground Travels), in which Nicolai Klim falls through a cave while spelunking and spends several years living on both a smaller globe within and the inside of the outer shell.

Other notable pre-20th century examples include Giacomo Casanova's 1788 Icosaméron, a 5-volume, 1,800-page story of a brother and sister who fall into the Earth and discover the subterranean utopia of the Mégamicres, a race of multicolored, hermaphroditic dwarfs; Symzonia: A Voyage of Discovery by a "Captain Adam Seaborn" (1820) which reflected the ideas of John Cleves Symmes, Jr.; Edgar Allan Poe's 1838 novel The Narrative of Arthur Gordon Pym of Nantucket; and George Sand's 1884 novel Laura, Voyage dans le Cristal where unseen and giant crystals could be found in the interior of the Earth.

The idea was used by Edgar Rice Burroughs, the creator of Tarzan, in the seven-novel "Pellucidar" series, beginning with "At the Earth's Core" (1914). Using a mechanical drill, his heroes discover a prehistoric world 500 miles below the surface that is lit by an inner sun called Pellucidar.

More recently, the idea has become a staple of science fiction, appearing in print, in film, on television, in comics, role-playing games, and in many animated works.

See also

Bibliography

• Seaborn, Captain Adam. Symzonia; Voyage of Discovery. J. Seymour, 1820.
• Kafton-Minkel, Walter. Subterranean Worlds. Loompanics Unlimited, 1989.
• Standish, David. Hollow Earth. Da Capo Press, 2006.

References

External links

• The Hollow Earth – from The UnMuseum
• At the Earth's Core, by Edgar Rice Burroughs
• Steve Currey's journey.
• The North Pole Inner Earth Expedition official website
• Skeptic Dictionary: Hollow Earth