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What is the theory? - The hollow Earth theory posits that we live on the outer layer of our planet, however the inside is hollow, and may be home to a completely different world.

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What does this earth look like? - The theory has led to many ideas about what this inner Earth would look like, including anything from vague references to luminous atmospheres to a lush tropical paradise with advanced species.

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How did it come to be? -

While the hollow Earth theory actually came to be through a scientific hypothesis, the root of the idea has been around for thousands of years.

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Roots in mythology -

Before science had anything to do with it, numerous cultures have held the belief that there is a hidden world below our feet.

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Ancient Greeks -

The Ancient Greeks believed that caverns in the Earth led to the underworld. They also believed in a place called Tartarus, located even deeper than the underworld. This would've been where Zeus imprisoned the Titans.

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Celtics -

In Celtic mythology, a cave called Oweynagat was the gate to the underworld. Supposedly it is where fairies and demons lured mortals to their doom.

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The Mandan people -

The Mandan people supposedly lived underground, but found out about the “Earth plain” when they climbed a vine out to the surface. After describing what they had seen, some of their people climbed the vine to the surface until it finally snapped. The legend suggests that many of the Mandan people are still left underground. The Mandan are a Native American tribe of the Great Plains, and have lived primarily in what is now North Dakota.

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Hinduism -

"Patala" is the name of the underworld in Hindu mythology. It is supposedly the lowest realm.

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Trobriand Islands -

People from the Trobriand Islands, in Papua New Guinea, hold the belief that their ancestors came from a subterranean land by the name of "Obukula."

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Chinese mythology -

The supposed realm of the dead in Chinese mythology, Diyu is made up of various subterranean caverns and chambers. The number of levels varies depending on Buddhist and Taoist interpretations.

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Christianity -

And, of course, there is the idea of hell within Christianity, which is frequently referred to as a location “below” us, whereas heaven is up above.

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From myth to science -

While the hollow Earth theory clearly has a basis within mythology and religion, it became its own scientific idea in the late 1600s.

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Edmond Halley -

In 1692, astronomer Edmond Halley (of Halley’s Comet fame) was a proponent of the idea of a hollow Earth from a more scientific perspective, suggesting that the Earth had inner shells, a core, and magnetic poles.

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Magnetic field -

The reason for this assumption was the shifting of Earth’s magnetic field. He hypothesized that it was due to the Earth being made up of concentric circles, with a hollow space in the middle.

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And there was life -

Not only did he posit that the center of the Earth was hollow, but he also suggested that there was life. He suggested that living things could exist between the concentric circles, and that there must be light between them.

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Comparing them to apartments -

In support of this statement, Halley said: “We ourselves, in Cities where we are pressed for room, commonly build many Stories, one over the other, and thereby accommodate a much greater multitude of Inhabitants.”

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Almost there -

While you may be looking at this theory as ridiculous, Halley was actually quite close to reality. The Earth is made up of layers, and we are on the outermost one (the crust). There is even some basis for the shifting of magnetic fields!

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John Cleves Symmes Jr. -

Similarly to Halley, John Cleves Symmes Jr. also believed in a multi-layer world with a hollow core. The differentiation? We could enter this world through holes (pictured) at the North and South Pole. He even attempted to go to the North Pole himself.

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On tour -

Symmes wanted everyone to know about this theory, so he toured the US in the early 1800s. He ended up influencing numerous people, including…

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Jeremiah Reynolds -

While Symmes never managed to create an expedition, Jeremiah Reynolds did. A newspaper editor, Reynolds was convinced by Symmes' theory and organized an expedition to Antarctica. Unfortunately, the ships never made it to their destination.

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Concave hollow Earth -

There was also a theory, put forth by physician and alchemist Cyrus Teed, that we actually lived in the center of the hollow Earth. He created a cult called Koreshan Unity in the late 1800s based on the idea.

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Disproving the theory -

In 1774, the idea of a hollow Earth was categorically disproven by a mathematician named Charles Hutton.

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Schiehallion experiment - The experiment measured the mean density of the Earth, thereby proving that it was too dense to be hollow. Hutton was one of the members involved.

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Earthquakes -

Seismic waves also disprove a hollow Earth. The time it takes for seismic waves to move through the Earth is in contradiction to the concept of a completely hollow sphere.

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The move to science fiction -

While this theory may sound straight out of a science fiction novel, in reality, the scientific theory came first! However, there have been many pieces of literature based around the idea of a hollow Earth.

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‘Journey to the Center of the Earth’ -

Jules Vernes’ 1864 novel was one of the first to discuss the idea of inner worlds (though Dante’s ‘Inferno’ did predate it). This novel opened up a new subgenre for science fiction writers.

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‘At the Earth’s Core’ -

First a book and then a film, Edgar Rice Burroughs’ novel dealt with the hollow Earth realm called Pellucidar.

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‘The Goddess of Atvatabar’ -

Using Symmes’ interpretation of a hollow Earth, William R. Bradshaw created the world of Atvatabar. Entering through a Symmes hole (the entrance at the North Pole), Atvatabar is shown as an advanced society with many spiritual motifs.

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Hollow Earth theorists today -

Despite the theory being disproved, there are still people who believe in the idea of a hollow Earth today. Many use conspiracy theories to justify the lack of evidence, suggesting that much of the information has been covered up.

See also: Conspiracy theories that turned out to be true.

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