Fact-checking the ‘hollow earth’ conspiracy theory

Giant animals. Beautiful forests. Extraterrestrial technologies. That is all inside our planet, according to an Instagram post that claims the Earth is hollow and has a civilization living inside.

Scientists once took claims like this seriously, according to "Hollow Earth," a book by David Standish. English astronomer Edmond Halley proposed to the Royal Society of London in the 1690s that the Earth consisted of nested, spherical shells that spun in different directions and surrounded a central core. Halley thought the space between shells may have had luminous atmospheres that might have supported life.

American officer John Cleves Symmes expanded Halley’s theory in the 1810s by claiming that those spheres could be accessed through holes in both poles.

Even though advancing science has debunked those ideas, they survive online.

One recent Instagram post claimed that there is "an enormous void" with a "stunning magnetic anomaly" or a "massive gravity anomaly" beneath Antarctica’s ice. A "different world" or a "mythic land" exists in that space, where giant animals roam in green forests surrounded by "extraterrestrial technologies."

Elsewhere, believers propose that aliens, Vikings, ancient civilizations, and Nazis escaping Allied forces all live in this place. They also claim that Adam and Eve from the Bible were banished from the inside of the Earth to the outside, and the Lost Tribes of Israel migrated from the outside to the inside.

The Instagram post also claimed, echoing Symmes, that the Earth’s interior could be reached through polar holes and that elites are trying to hide those entrances by manipulating polar satellite images and banning travel to Antarctica.

The post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

Since Halley and Symmes, scientists have amassed evidence proving the Earth isn’t hollow. Andrew Campbell, a professor of geophysics at the University of Chicago, said the most straightforward explanation is that Earth’s density is greater than that of the rocky layer comprising its crust. 

Earth has a density of 5.5 grams per cubic centimeter on average (counting all the mass of the planet) while rocks in the crust have a density of 2.7 grams per cubic centimeter on average, Campbell said. If our planet were hollow, its density would be lower, not greater, than the density of its crust.

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Scientists cannot visit the Earth’s interior, but have other means for gauging its composition, Campbell said. For example, they can analyze the waves produced by earthquakes that run through the Earth’s interior, slowing and changing paths as they encounter the boundaries of its internal layers.

The Instagram post indicates that satellite images always come with the poles removed, blurred or covered. One picture included in the post, produced by NASA’s ICESat satellite, shows all of Antarctica except the South Pole. 

The post claims that this is part of a plot to keep underworld entrances hidden. But NASA scientist Thorsten Markus explained that satellites often skip parts of the Earth’s surface because of how they spin around the world. ICESat satellites, for example, do not cover the poles. 

"We pick the inclination based on our science requirements" and "the poles themselves are not that interesting so we skip them," said Markus.

Finally, there are multiple examples of satellite images that show the North and South poles in great detail. And although American explorers traveling to Antarctica need to notify the State Department about their plans, they can still access the South Pole (and the North Pole) independently or on cruises, airplanes and balloons managed by travel companies.

Pressure and heat inside the Earth make human visits impossible. 

"Life is possible to very limited depths in the crust, but not deeper than that," Campbell said. "In Earth’s mantle and core, the pressures and temperatures are so great that the chemistry of life is not possible — carbon-rich organic molecules will react to form diamond and other materials."

Campbell believes this impossibility of access makes the depths of the Earth so fascinating to people. "The interior of the planet is inaccessible to human visitation, and probably always will be," he says, "so people conjure fantasies about what lies there."

An Instagram post claims that there is "an enormous void" below Antarctica, that a "different world" exists there, and that it can be accessed through a hole in Antarctica. The post also claims that elites are conspiring to keep that a secret.

Scientists are sure that the Earth is not hollow, partly because it’s much denser than the rocks found on the surface. Elites are not hiding the poles from the public — they can be seen in satellite images and visited by tourists. And life is impossible deep inside the Earth.

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