Journey to the Subterranean World

It is the morning of the 10th of April 1818 in St. Louis, Missouri. You open your letterbox to see a certificate verifying the sender’s sanity and a pamphlet that reads: 


I declare the earth is hollow, and habitable within; containing a number of solid concentric spheres, one within the other, and that it is open at the poles 12 or 16 degrees; I pledge my life in support of this truth, and am ready to explore the hollow, if the world will support and aid me in the undertaking.”

Credit: John Cleves Symmes, Jr. / Public domain

The pamphlet (formally known as “No.1 Circular”) was seen by some as revolutionary, by many as erroneous but in reality, it was a derivation of an already existing geophysical idea that originated in England by Edmond Halley. The notion that lost civilizations, peculiar animals and the underworld lies beneath our feet has its roots in ancient traditions, mythology and folklore. However, it wasn’t until the 17th century (by Edmond Halley) that the hollow-earth theory found its way into science. 

Edmond Halley’s Hollow Earth

Edmond Halley, as most scientists did (and still do), sought to find answers to questions that perplexed him. As a friend of Sir Isaac Newton, Halley based his hollow earth theory from deductions drawn from Newton’s Principia- the notorious book that entailed Newton’s laws of motion. In the Principia, Newton demonstrated how the Earth was less dense than the moon. Although this was later disproved, Halley interpreted this finding to mean that the Earth was somewhat hollow.  

“Sir Isaac Newton has demonstrated the Moon to be more solid than our Earth, as 9 to 5; why may we not then suppose four ninths of our globe to be cavity?”

Edmond Halley

Halley also possessed a fond interest in magnetic declination. This is the difference between the Earth’s true north and the magnetic north. One question he contemplated was why did the value of the magnetic declination shift over time? 

A 2D illustration of Edmund Halley’s “Hollow Earth” theory Credit: Rick Manning / CC BY-SA

In 1683, Halley conjectured that the Earth has four magnetic poles, but at the time he could not prove their existence nor account for their gradual shifting movements. Less than ten years later he published a scientific paper titled “An account of the cause of the change of the variation of the magnetic needle; with an hypothesis of the structure of the internal parts of the earth”, which he believed proved that four magnetic poles exist. The conclusion he reached was peculiar and one that depended on the Earth’s internal structure being hollow. He theorized that the Earth consisted of an outer shell 800 km thick -where we live- and three concentric equidistant inner spheres (also referred to as shells or circles). Where do the four magnetic poles lie? Halley believed that one pair existed fixed in the outer shell, and the other pair existed in constant motion in the inner shell. The magnetic poles in the shells are slightly misaligned with each other and when the shells rotate coaxially at different speeds, this causes the magnetic declination observed at the surface of the Earth. He went on to state that the different spheres did not collide due to the presence of gravity and suggested that each one “might support life” because above it existed a luminous atmosphere. 

“Hollow, and Habitable Within”: Symmes’ Theory 

John Cleves Symmes, Jr. and his hollow earth.

One of the firmest believers and perhaps most famous proponents of the hollow Earth theory was John Cleves Symmes Jr- an amateur geographer, lecturer, American Army officer and trader. Symmes often marked himself as the pioneer of this theory and swore that he had never read previous similar theories and was only inspired by the abundant evidence provided by the natural phenomena around him. It was said that due to his immense conviction of the concavity of the Earth, he moulded anything he saw or read as evidence to fit his theory. 

For example, Symmes Jr asserted in a letter to his stepson that:

“from the curious formation of [Saturn], I infer that all planets and globes are holow.”

And gave no further explanation as to how Saturn proved that the Earth was hollow. He assumed that since Saturn has rings, every other planet must have rings too-ours found inside the earth. Another piece of “evidence” that he felt proved his theory was the fact that debris and driftwood were constantly found washed up on the shores. The only explanation Symmes had for this was that there had to be giant openings in the north and south pole allowing material from the interior of the hollow Earth to float into our oceans. 

Symmes’ original theory was similar to Halley’s in the sense that it contained several concentric spheres (five to be exact) with hollow spaces between them. What differentiated his theory was the openings located in Antarctica and the Arctic. For the average person, the idea that there exists a hole in a very remote and inaccessible region does not seem too bizarre. However, the location of Symmes’ openings spread across several areas that were explored previously and inhabited. Critics also pointed out the flaw in his claim that the Earth’s interior is “a warm and rich land, stocked with thrifty vegetables and animals if not men” if there was no apparent source of light inside. How did Symmes counter this? He claimed that light rays from the sun would refract into the hole and the surface of the inner spheres would reflect the light, illuminating the interior of the Earth. Since the opening’s rim curvature is very slight, the light refraction created an ‘optical illusion’ which meant that boreal inhabitants were unaware they were living inside the earth rather than at the poles. 

According to Duane A. Griffin, the most salient proponent of Symmes theory was Ohio newspaper editor Jeremiah Reynolds who started as his biggest supporter then ended up his rival and legacy bearer. Reynold’s convinced Symmes to tour the east of the United States as that was the only way he’d gather supporters for his expedition. While touring In 1825, the Chancellor of Russia requested Symmes’ presence for a polar expedition he was planning. Despite rejecting the invitation, Symmes took advantage of this and as Elmore Symmes stated, Symmes informed his audience that “he was pledged to Count Romanzoff, Russian Chancellor, for an exploring expedition unless his countrymen sent him north on their own account.” This sparked a sense of nationalism into his theory and gained him substantial popularity. Meanwhile, a rivalry sparked between Symmes and Reynolds, for reasons that are unclear and eventually their partnership was terminated. Despite his growing success, Symmes dreams of a polar expedition were unrealized as he passed away in 1814.

The Legacy Left Behind

There is no doubt that Symmes’ theory was a creative notion conjured by his boundless imagination. He even went as far as suggesting that monsoons “may be supplied by winds sucked into one polar opening and discharged through the other”. However, to assert that his theory was pointless would be a grave mistake. Before he toured the United States, the Earth’s interior was an enigma and world maps had many undocumented regions. His theory set in place a domino effect in the advancement of polar exploration. 

If it wasn’t for Symmes, Reynolds wouldn’t have lobbied congress to fund an expedition to the South Pacific which resulted in the establishment of Antarctica as a continent. If not for Symmes, many would have not taken the time to seriously investigate the Earth’s interior. 

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