Flat Earth

Contrary to the popular image of medieval scholars insisting the Earth was flat, the sphericity of the Earth was established Greek knowledge by the time of Eratosthenes in the 3rd century BCE, and virtually every major medieval European scholar accepted a spherical Earth as settled fact. The "medieval flat earth" belief is itself a myth — largely manufactured in the 19th century, beginning with Washington Irving's fictionalised 1828 biography of Columbus, which invented a scene of scholars warning him he'd sail off a flat world's edge. Historians John William Draper and Andrew Dickson White later amplified the myth further in the 1870s, using it to support a broader (and largely discredited) narrative pitting science against religion.

The actual modern Flat Earth movement traces to one specific person: Samuel Birley Rowbotham, writing under the pen name "Parallax." In 1838, Rowbotham conducted his "Bedford Level Experiment" on a six-mile stretch of dead-straight canal in England, watching a boat through a telescope and concluding — because it remained visible longer than a curved Earth should allow — that the surface was flat. He never accounted for atmospheric refraction, the same optical bending of light near a surface that produces desert mirages, which fully explains his result on a genuinely spherical Earth. He published the pamphlet in 1849 and expanded it into the book Zetetic Astronomy: Earth Not a Globe in 1865.

Rowbotham's proposed model — a disc centred on the North Pole, with Antarctica reimagined as an ice wall ringing the disc's edge — is, essentially unchanged, the exact model that still circulates today.