Flat Earth: How a 1838 Canal Experiment Became a YouTube Movement

ARCHIVE FILE · Theory explainer. Key dates: 1838, 1849, 1956, 2015, 2018, 2024. This is not breaking news. It’s part of the Redacted Weekly evergreen archive. We explain conspiracy theories; we don’t endorse them.

People have known Earth is round for well over two thousand years. In the Hellenistic period, Eratosthenes produced the first known measurement of its circumference. So the modern flat Earth movement isn’t an ancient belief that survived. It’s a 19th-century invention that was nearly dead before YouTube brought it back.

CASE FILE · RW-ARC-CON-007
Subject: The modern flat Earth conspiracy theory
Founder: Samuel Rowbotham (“Parallax”), 1816-1884
Founding “experiment”: Bedford Level, England, 1838
Organized by: International Flat Earth Research Society (Samuel Shenton, 1956)
Revival: Online, since about 2015
Status: Debunked
Edge of the world: Reportedly guarded by Antarctica. Tourists keep coming back.

Origin

Samuel Rowbotham, an English writer, ran what he called the Bedford Level experiment on a long, straight drainage canal in 1838. He concluded he could see objects farther away than a curved Earth would allow. In 1849 he published a pamphlet, Zetetic Astronomy, under the pen name “Parallax”, and later expanded it into the book Earth Not a Globe.

His model is still the one most flat-Earthers use: a flat disc centered on the North Pole, edged by a wall of ice, Antarctica, with the Sun and Moon about 3,000 miles overhead.

Interest faded after the First World War. In 1956, Samuel Shenton founded the International Flat Earth Research Society, better known as the Flat Earth Society. When Shenton died in 1971, California’s Charles K. Johnson took over the American branch.

The revival

Since about 2015, the internet has driven a resurgence. YouTube videos, conferences and celebrity comments brought the idea to people who had never heard of Rowbotham. A 2018 YouGov poll reported that “just 66% of millennials firmly believe” Earth is round. The documentary Behind the Curve (2018) followed prominent believers, including Mark Sargent and Patricia Steere.

What believers claim

These are claims, not facts.

• Claim: Earth is a flat disc, and the “globe” is a hoax.
• Claim: NASA and other agencies conspire to fake photos and evidence of a spherical Earth.
• Claim: Antarctica is an ice wall around the edge, guarded to stop people from finding out.
• Claim: Water always lies flat, so the oceans can’t curve.

Tested by believers themselves

Some of the best debunks came from flat-Earthers’ own experiments:

• GlobeBusters, a YouTube show, used a ring laser gyroscope to show Earth doesn’t rotate. It detected the real 15-degree-per-hour rotation. They blamed the device.
• On 14 December 2024, pastor Will Duffy paid to fly flat-Earth believers to Union Glacier Camp in Antarctica for the “Final Experiment.” They had to concede they saw the 24-hour midnight sun, which a flat-disc model can’t produce. Not all of them changed their minds.

Footage

We’re not embedding video for this case. The featured image is NASA’s Apollo 17 “Blue Marble,” which is public domain. (Description method: Wikimedia Commons file metadata; facts from Wikipedia’s sourced article “Modern flat Earth beliefs”; no footage viewed.)

Grades