Flat Earth: The Modern Revival of a Pre-Eratosthenes Cosmology.

What the modern Flat Earth movement is, in a paragraph.

The modern Flat Earth movement is a loose, mostly Anglophone, Internet-driven anti-establishment movement that argues Earth is not a globe but a flat disc, generally with the Arctic at the center and Antarctica as a circumferential ice wall, and that the entire scientific and governmental apparatus of cosmology — NASA, the European Space Agency, Roscosmos, the major university astronomy departments, the commercial aviation industry, and the surveying profession — is either complicit in or directly orchestrating a global deception of the public. The movement's intellectual genealogy runs from the nineteenth-century writings of Samuel Birley Rowbotham, through the small but persistent twentieth-century Flat Earth Society of Samuel Shenton and Charles K. Johnson, to a post-2010 revival on YouTube, podcasts, and social media that produced the annual Flat Earth International Conference (FEIC) from 2017 onward and brought millions of viewers into contact with the position for the first time in modern memory. The movement is internally heterogeneous — on the specifics of the model, on whether the dome is solid or atmospheric, on whether gravity exists or whether all observed gravitational effects are buoyancy, on whether the sun is small and near or large and distant, on whether space exists at all — but is unified by a core methodological claim: that direct observation by ordinary people, untrained in mainstream science and free of the institutions that produce it, can detect Earth's true shape, and that this direct observation produces flat-Earth conclusions. The standard empirical observations — horizon disappearance of ships hull-first, the lunar eclipse Earth shadow, the southern-hemisphere season pattern, the Foucault pendulum, the Coriolis effect, GPS, the trans-polar flight paths, the 2017 Bob Knodel ring laser gyroscope experiment, and the 2019 follow-on documented in the Netflix film Behind the Curve — all support a spherical, rotating Earth. The movement's persistence in the face of those observations is its actual subject; the cosmological claim is the surface presentation of a deeper rejection of institutional authority.

The documented record.

Eratosthenes and the ancient tradition

Eratosthenes of Cyrene, the chief librarian of the Library of Alexandria from approximately 245 BCE, measured Earth's circumference around 240 BCE by observing that on the summer solstice at Syene (modern Aswan), the sun was directly overhead and cast no shadow in a deep well, while on the same day at Alexandria, approximately 800 kilometers to the north, the sun cast a shadow at an angle of 7.2 degrees from vertical, as measured against a vertical pole or obelisk. Verified From the ratio 7.2/360, Eratosthenes computed the distance between Syene and Alexandria as 1/50 of Earth's circumference, and from the surveyed distance of 5,000 stadia between the two cities, derived a circumference of 250,000 stadia (later refined to 252,000). The accuracy of this figure depends on which stadium length is used (Greek scholars used multiple values); modern reconstruction estimates the result to be within 1 to 15 percent of the modern figure of 40,075 kilometers. The method was reproducible, was reproduced by Posidonius in approximately 100 BCE with a comparable result, and entered the mainstream of Hellenistic and subsequently Roman, Byzantine, Islamic, and medieval Christian cosmology [1].

The widely-repeated claim that the medieval Christian church believed in a flat Earth is itself a nineteenth-century invention, traceable to the work of Andrew Dickson White and John William Draper in the 1870s. The actual medieval Christian and Islamic mainstream — Bede, Sacrobosco, Aquinas, Dante, al-Khwarizmi, al-Biruni — consistently treated Earth as spherical [2]. The historical record is unambiguous on this point and is sometimes a surprise to readers who absorbed the contrary claim from twentieth-century textbooks. Verified

Samuel Birley Rowbotham and Zetetic Astronomy

The modern flat-Earth tradition begins with Samuel Birley Rowbotham (1816–1884), an English socialist of working-class origins who lectured and published under the pseudonym "Parallax." Verified In 1838 he conducted what came to be known as the Bedford Level experiment, observing a flag from a series of boats on the Old Bedford River — a straight six-mile stretch of canal through the Cambridgeshire Fens — and arguing that the flag remained visible at distances where the curvature of a spherical Earth should have placed it below the horizon. Rowbotham developed the experiment into a broader anti-Newtonian cosmology in his 1865 book Zetetic Astronomy: Earth Not a Globe!, named for the Greek philosophical term zetesis (inquiry). The "zetetic method," in Rowbotham's articulation, claimed to derive conclusions from direct observation while rejecting the mathematical and theoretical apparatus of established science [3].

The 1870 follow-on experiment by Alfred Russel Wallace, conducted at Rowbotham's contemporary John Hampden's challenge for a £500 wager (the Newton wager), used markers at three points along the same Bedford Level six-mile stretch and demonstrated the expected curvature: the central marker, sighted between the two terminal markers, was higher by approximately the expected three feet, in direct contradiction of Rowbotham's earlier reported findings. Verified Wallace was judged the winner of the wager by a neutral referee. Hampden refused to pay, filed defamation claims against Wallace, and the case produced decades of litigation; Rowbotham himself did not publicly acknowledge the result [4].

The twentieth-century Flat Earth Society

After Rowbotham's death, his work was continued in attenuated form by his followers in a Universal Zetetic Society, and then in 1956 by Samuel Shenton (1903–1971), who founded the International Flat Earth Society in Dover, England. Verified Shenton was a sign-painter and lay preacher; he corresponded with the British and American press through the 1960s, providing flat-Earth commentary on the space race for journalists who treated him as a curiosity. After Shenton's death in 1971, leadership of the society passed to Charles K. Johnson (1924–2001), an American who relocated the headquarters to Lancaster, California, and ran the society from his home until his death in 2001. Johnson maintained a paid membership that peaked at approximately 3,500 in the 1990s, published a newsletter (Flat Earth News) on a roughly quarterly basis, and corresponded with journalists in the same role Shenton had occupied. The Apollo moon landings, in Johnson's view, were a Hollywood production; the photographs of Earth from space were falsified [5].

The Johnson-era society did not survive his death intact. A 2004 fire destroyed many of the society's records; subsequent revivals under Daniel Shenton (a relative of Samuel Shenton; founded a new Flat Earth Society in 2009) and others have produced loosely-affiliated successor organizations. None of these has the institutional continuity of the Johnson period, and the modern Internet movement is not primarily organized through them.

The post-2010 revival

The current Flat Earth movement is substantially distinct from its predecessors in scale, character, and medium. Verified Beginning approximately 2014–2015, a network of YouTube channels — Mark Sargent's Flat Earth Clues, Eric Dubay's videos on his channel, Robbie Davidson's Celebrate Truth, and others — produced flat-Earth content that, through the YouTube recommendation algorithm in that period, achieved view counts in the tens of millions cumulative. The movement attracted public attention through high-profile endorsements: rapper Bobby Ray Simmons (B.o.B) in 2016, basketball player Kyrie Irving in 2017, comedian Eddie Bravo and others. The Flat Earth International Conference, organized by Robbie Davidson, held its first meeting in Raleigh, North Carolina, in November 2017, drew approximately 500 attendees, and has continued annually since [6].

The Netflix documentary Behind the Curve, directed by Daniel J. Clark and released in 2018, followed the leading figures of the modern movement — Sargent, Patricia Steere, Bob Knodel, Jeran Campanella, and others — over approximately two years, including footage of the FEIC conferences and of two empirical experiments designed and conducted by movement members. The film documented both experiments producing results contradicting flat-Earth claims; the movement members' on-camera reactions to those results form the documentary's central analytic moment [7]. Verified

The movement's own experiments

Two movement-designed experiments documented in Behind the Curve are notable as a substantive empirical episode within the modern Flat Earth movement.

The first was conducted by Bob Knodel using a Sm750-20 ring laser gyroscope (an instrument used in aviation inertial navigation systems for precise rotation measurement). Verified Knodel and his collaborator set up the gyroscope expecting to measure zero rotation if Earth were stationary as the flat-Earth model assumes. The instrument measured approximately 15 degrees of rotation per hour — the expected value for Earth's rotation at the latitude where the experiment was conducted. Knodel, on camera, acknowledged the unexpected measurement and stated that the team would proceed to attempt to explain why the instrument was producing the value it produced [7].

The second experiment, designed by Jeran Campanella, used a board-mounted laser light at one end of a long body of water and three large boards with synchronized holes positioned at intervals along the water. Verified The expected flat-Earth result was that the laser would pass through all three holes; the expected spherical-Earth result was that the laser would not align with all holes due to the curvature of the water surface. Campanella conducted the experiment, the laser did not pass through the three holes, and Campanella on camera produced the same response: that further investigation would be required to explain the result. Neither experiment, to public knowledge, has subsequently been retracted or revised by the experimenters in a way that altered their flat-Earth position [7].

Standard observations contradicting the flat-Earth model

The standard empirical evidence for a spherical, rotating Earth is large and accessible to non-specialists. The most direct observations include: Verified

• Horizon-line ship disappearance. Ships moving away from shore over open water disappear hull-first, then mast-last, in the manner predicted by a curving water surface. The effect is observable from beaches and is the oldest documented argument for sphericity [1].
• Lunar eclipse Earth-shadow. During a lunar eclipse, the shadow Earth casts on the Moon is curved. Aristotle noted this around 350 BCE; the observation requires no instrument more sophisticated than the naked eye and a full moon during an eclipse.
• Southern-hemisphere seasons and the southern celestial pole. Southern-hemisphere observers see different stars than northern-hemisphere observers, see the Sun in the northern part of the sky at midday, and have summers when the Northern Hemisphere has winters. A flat-disc model centered on the North Pole cannot reproduce these observations.
• The Foucault pendulum. First demonstrated by Léon Foucault in 1851 at the Pantheon in Paris, the rotation of the plane of swing of a long-suspended pendulum demonstrates Earth's rotation directly; the rate of rotation varies with latitude in the manner predicted by a rotating sphere.
• The Coriolis effect. Observable in weather systems (hurricanes spinning counterclockwise in the Northern Hemisphere, clockwise in the Southern) and in long-range ballistics; predicted by a rotating spherical Earth.
• GPS. The Global Positioning System functions by trilateration from satellites in known orbits; the positioning model is implemented for a spherical Earth and produces position fixes accurate to within meters globally. If Earth were flat, GPS would produce systematic position errors that are not observed.
• Commercial flight paths. Long-haul flight routes — including the Madrid-to-Tokyo trans-polar routes, the Santiago-to-Sydney routes, and others — follow great-circle paths on a globe and are nonsensical on the standard flat-Earth disc projection.
• Direct photography from orbit and the Moon. Photographs of Earth taken from the International Space Station, from various deep-space missions, and from the Apollo program all show a spherical body. The flat-Earth response is to assert that all such photographs are forged.

The flat-Earth model and its sub-positions.

The modern movement is internally divided on the specifics of the model. Common claims include: Claimed

• The disc. Earth is a flat disc, generally with the Arctic at the center.
• The ice wall. Antarctica is not a continent but a continuous ice barrier surrounding the disc, patrolled by Antarctic Treaty signatories to prevent civilians from reaching the edge.
• The dome / firmament. A solid or quasi-solid dome covers the disc, on the inside of which the stars are fixed. Some versions identify the dome with the biblical raqia.
• NASA conspiracy. All photographs of Earth from space are forged. The Apollo missions did not occur. The International Space Station does not exist. Satellites either do not exist or are high-altitude balloons.
• Gravity as buoyancy. Gravity does not exist; all observed gravitational effects are explained by density and buoyancy.
• The Sun and Moon. The Sun and Moon are local, small, and relatively close (typically 3,000 to 6,000 km altitude in popular models); they circle above the disc and produce the appearance of day and night through their local illumination rather than through Earth's rotation.

The sub-positions are not mutually consistent. The movement's response to internal contradictions, where these are raised, is generally to defer the question to ongoing inquiry rather than to adjudicate among the sub-positions. The model's specifics are downstream of the core methodological commitment: rejection of mainstream cosmology in favor of direct lay observation. Disputed

The genuine analytic questions.

The cosmological question — whether Earth is round — is closed; it has been closed for approximately 2,260 years. The interesting open questions about Flat Earth are not cosmological but social and analytic.

Why does the movement persist in the face of its own contradictory results?

The Knodel ring-laser gyroscope result and the Campanella laser-and-boards result, both performed by committed flat-Earth advocates with their own equipment and on their own designs, produced spherical-Earth-consistent results. The continued advocacy of flat-Earth positions by the experimenters who obtained those results is the central social-scientific datum of the modern movement. Standard social-psychological explanations include cognitive dissonance reduction, the role of identity-protective cognition, the social cost of leaving a community in which one has invested heavily, and the structural difficulty of admitting public error in front of one's audience. The movement provides a relatively unconfounded modern case study in these dynamics [8].

How did the YouTube recommendation algorithm function in the 2014–2018 period?

The modern movement's growth between 2014 and 2018 was substantially driven by the YouTube recommendation algorithm of that period, which optimized for watch-time and produced rabbit-hole pathways from mainstream content into Flat Earth and related conspiratorial content. YouTube began modifying these recommendation pathways in 2019, and the rate of growth of the movement appears to have slowed but not reversed. The platform-mechanics question — how recommendation systems shape exposure to anti-establishment content — is well-documented in journalistic and academic work but remains incompletely resolved in the present period [9].

The relationship to other anti-establishment movements

Modern Flat Earth substantially overlaps in membership and rhetorical style with other contemporary anti-establishment movements: vaccine skepticism, climate-change denial, QAnon and adjacent political movements, and the broader "do your own research" methodological position. The overlap is not complete and the movements are not interchangeable, but they share a common epistemological structure: lay observation prioritized over institutional consensus, with institutional consensus reinterpreted as evidence of conspiracy.

The religious dimension

A substantial fraction of the modern movement, including organizers Robbie Davidson and others, frame Flat Earth in explicitly Christian-fundamentalist terms, with the dome (raqia) and the disc as biblically prescribed cosmology and the scientific establishment as a satanic or globalist deception. This dimension is not universal in the movement but is a non-trivial sub-current. The interaction of religious literalism with anti-establishment epistemics is its own analytic question that the file is too small to resolve.

Primary material.

• Rowbotham, Samuel Birley (as "Parallax"). Zetetic Astronomy: Earth Not a Globe! First edition 1865; expanded editions through the 1870s.
• Wallace, Alfred Russel. Correspondence and contemporaneous reports on the 1870 Bedford Level experiment for the Newton wager.
• The Flat Earth Society archive (Johnson era), partially destroyed in the 2004 fire; surviving material held by family and the Daniel Shenton-era society.
• Flat Earth International Conference proceedings, 2017–present (Robbie Davidson, organizer).
• Clark, Daniel J. (director). Behind the Curve. Netflix documentary, 2018.
• Eratosthenes's measurement: reconstructed from references in Cleomedes (1st century BCE/CE) and subsequent classical sources.
• Foucault, Léon. Reports on the 1851 Pantheon pendulum demonstration.
• Modern empirical surveys of the Flat Earth movement by Asheley Landrum (Texas Tech) and others (2018–2022).

The sequence.

1. c. 350 BCE Aristotle, On the Heavens, records evidence for spherical Earth from the curved Earth-shadow on the Moon in lunar eclipses.
2. c. 240 BCE Eratosthenes measures Earth's circumference using the shadow-angle method between Syene and Alexandria.
3. 1838 Rowbotham conducts the original Bedford Level experiment, reports a flat-Earth-consistent result.
4. 1851 Léon Foucault demonstrates Earth's rotation directly with the Pantheon pendulum.
5. 1865 Rowbotham publishes Zetetic Astronomy: Earth Not a Globe!
6. 1870 Wallace conducts the controlled Bedford Level experiment for the Newton wager and demonstrates curvature; Hampden refuses to pay; litigation ensues.
7. 1956 Samuel Shenton founds the International Flat Earth Society in Dover, England.
8. 1972 Charles K. Johnson assumes leadership of the society, relocates to Lancaster, California.
9. 2001 Death of Charles K. Johnson; the Johnson-era society effectively dissolves.
10. 2004 Fire destroys much of the Johnson-era society's records.
11. 2009 Daniel Shenton founds a new Flat Earth Society as an Internet-era successor.
12. 2014–2015 Mark Sargent, Eric Dubay, and other YouTube channels begin publishing flat-Earth content; views grow rapidly via YouTube recommendation.
13. 2016–2017 High-profile celebrity endorsements (B.o.B, Kyrie Irving, Eddie Bravo).
14. November 2017 First Flat Earth International Conference held in Raleigh, North Carolina.
15. 2017–2018 Bob Knodel ring-laser gyroscope experiment; Jeran Campanella laser-and-boards experiment; both produce results contradicting the flat-Earth model.
16. 2018 Netflix releases Behind the Curve.
17. 2019 YouTube modifies its recommendation algorithm to reduce promotion of conspiratorial content.
18. 2020–2026 The movement persists at roughly stable scale, with continued annual FEIC conferences and continued internal debate about model specifics, without producing experimental results that vindicate the cosmology.

Cases on this archive that connect.

The Moon Landing Hoax (File 038) — a substantially overlapping anti-establishment cosmological position. Flat Earth requires the moon-landing-hoax claim as a sub-component (if Earth is flat, the Apollo photographs must be forged); the broader moon-landing-hoax community is not, however, all flat-Earth.

QAnon (File 046) — an adjacent anti-establishment movement with substantial membership overlap and shared epistemological structure ("do your own research," institutional consensus as conspiracy).

Chemtrails (File 111) — another contemporary anti-establishment science-rejection movement with overlapping membership and similar dynamics.

The Reptilian Elite (File 117) — the broader David Icke synthesis of anti-establishment cosmology; not all Flat Earth advocates accept Icke's broader claims, but there is non-trivial overlap.

Full bibliography.

1. Cleomedes, On the Circular Motions of the Celestial Bodies, 1st century BCE/CE, the classical source preserving Eratosthenes's method. Modern translation: Bowen and Todd, University of California Press, 2004.
2. Russell, Jeffrey Burton. Inventing the Flat Earth: Columbus and Modern Historians. Praeger, 1991. The standard work on the nineteenth-century invention of the "medieval Christians thought the Earth was flat" myth.
3. Rowbotham, Samuel Birley (as "Parallax"). Zetetic Astronomy: Earth Not a Globe! First edition 1865.
4. Garwood, Christine. Flat Earth: The History of an Infamous Idea. Thomas Dunne Books, 2007. The standard scholarly history of the Rowbotham-Shenton-Johnson tradition.
5. Johnson, Charles K. Flat Earth News, newsletter, various issues, 1972–2001.
6. Davidson, Robbie. Flat Earth International Conference proceedings, 2017–present.
7. Clark, Daniel J. (director). Behind the Curve. Documentary film, Delta-V Productions, 2018; Netflix distribution.
8. Landrum, Asheley R. and Olshansky, Alex. "The role of conspiracy mentality and worldview in predicting belief in the flat Earth." Texas Tech University research, presented 2018–2020.
9. Roose, Kevin. "The Making of a YouTube Radical." The New York Times, June 8, 2019. Reporting on YouTube's recommendation algorithm and conspiratorial content pathways.
10. Foucault, Léon. "Demonstration physique du mouvement de rotation de la Terre au moyen du pendule." Comptes Rendus de l'Académie des Sciences, 1851.
11. Aristotle, On the Heavens, Book II, c. 350 BCE. Modern English translation: Stocks, J. L., Oxford University Press, 1922.
12. U.S. National Oceanic and Atmospheric Administration. Reference materials on the Coriolis effect, geodesy, and the World Geodetic System (WGS84) underlying GPS.
13. International Civil Aviation Organization. Great-circle navigation publications and route documentation for trans-polar commercial routes (Madrid-Tokyo, Santiago-Sydney).