The Hollow Earth Theory

The Hollow Earth is a concept proposing that the planet Earth is entirely hollow or contains a substantial interior space. In recent decades, the idea has become a staple of the science fiction and adventure genres across films, most recently in Warner Bros’ MonsterVerse movies. Godzilla vs King Kong for example is loosely based on a real-life idea that dates back hundreds of years. Ancient civilizations had myths about an entire world that exists underground, hidden from the eyes of humans. In the 18th century, there were scientists who firmly believed in a ‘Hollow Earth’ theory, which postulated that the planet was actually hollow, and that there’s a massive, empty space under the surface. In most versions of the legend there are people or creatures living within it. This can vary depending on the theory or story, but Hollow Earth tales generally feature an entirely subterranean culture and community miles underneath the surface of our home planet. It’s not just fictional, though. There are people who claim our true Earth is hollow too. Some of those proponents even claim that there is a secondary sun within our planet, fueling those who live within the Hollow Earth. While it might seem utterly wild, it has as a theory at times been supported by famed scientists like Edmund Halley – who potentially came up with the idea – while also becoming a staple of science fiction storytelling as well as a popular conspiracy theory.

Over the centuries Hollow Earth has popped up in everything from Shakespeare to classic adventure novels. One of the earliest and most famous examples is Jules Verne’s Journey to the Center of the Earth which was first published in 1864. In that iconic story, a professor discovers a world beneath our world after breaking a runic cryptogram. Inside our Earth lies an entirely new world, one filled with prehistoric creatures, oceans, and strange anti-gravity wells which can help you travel across the world in mere hours (I’ll come back to those). But over one hundred years before that, Ludvig Holberg was also playing in the world of the Hollow Earth with his 1741 novel, Niels Klim’s Underground Travels. The story centers on a young man who falls into a cave and ends up in an interior landscape with its own space, sun, and even talking trees. Neither of these was the first fictional mention of the ever more popular concept though. I mentioned Shakespeare earlier and that would be due to A Midsummer’s Night’s Dream, which contains the line “I’ll believe as soon / This whole earth may be bored and that the moon / May through the center creep and so displease / Her brother’s noontide with Antipodes.” According to Hollow Earth enthusiasts, this is one of the earliest references to the theory, which actually predates Edmund Halley’s essay on the subject which brought it to the scientific forefront.

Edmond Halley in 1692 conjectured that the Earth might consist of a hollow shell about 800 km thick, two inner concentric shells and an innermost core. 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. In 1818, John Cleves Symmes, Jr. suggested that the Earth consisted of a hollow shell about 1,300 km thick, with openings about 2,300 km across at both poles with 4 inner shells each open at the poles. Symmes became the most famous of the early Hollow Earth proponents, and Hamilton, Ohio even has a monument to him and his ideas. He proposed making an expedition to the North Pole hole, thanks to efforts of one of his followers, James McBride. Though Symmes himself never wrote a book about his ideas, several authors published works discussing his ideas. Other Hollow Earth proponents have claimed a number of different locations for the entrances which lead inside the Earth. Other than the North and South poles, entrances in locations which have been cited include: Paris in France, Staffordshire in England, Montreal in Canada, Hangchow in China, and the Amazon Rainforest.

Despite these theories there is evidence contrary to the idea of a hollow Earth. The picture of the structure of the Earth that has been arrived at through the study of seismic waves is quite different from a fully hollow Earth. The time it takes for seismic waves to travel through and around the Earth directly contradicts a fully hollow sphere. The evidence indicates the Earth is mostly filled with solid rock (mantle and crust), liquid nickel-iron alloy (outer core), and solid nickel-iron (inner core). Another set of scientific arguments against a Hollow Earth or any hollow planet comes from gravity. Massive objects tend to clump together gravitationally, creating non-hollow spherical objects such as stars and planets. The solid spheroid is the best way in which to minimize the gravitational potential energy of a rotating 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.

The idea of a hollow Earth is nevertheless a common element of fiction, not only appearing as early as Ludvig Holberg’s 1741 novel Niels Klim’s Underground Travels, in which Nicolai Klim falls through a cave while spelunking and spends several years living on a smaller globe both within and the inside of the outer shell. Other notable early 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 dwarves; Vril published anonymously in 1819; 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; Jules Verne’s 1864 novel Journey to the Centre of the Earth, which showed a subterranean world teeming with prehistoric life; George Sand’s 1864 novel Laura, Voyage dans le Cristal where giant crystals could be found in the interior of the Earth; Etidorhpa, an 1895 science-fiction allegory with major subterranean themes; and The Smokey God, a 1908 novel that included the idea that the North Pole was the entrance to the hollow planet. In recent decades, the idea has become a staple of the science fiction and adventure genres across films such the MonsterVerse, television series (the third and fourth seasons of Sanctuary), role-playing games (e.g. the Hollow World Campaign Set for Dungeons & Dragons), and video games (Torin’s Passage and Gears of War).