Why Some People Still Think the Earth Is Flat

In 2018 a flat earther called Bob Knodel bought himself a ring laser gyroscope, about $20,000 of it, to settle the argument. A gyro that good picks up the rotation of whatever it is sitting on. If the Earth doesn't move, it reads nothing. If the Earth turns once a day, it reads a drift of fifteen degrees an hour.

It read fifteen degrees an hour.

There is a Netflix documentary about all this, Behind the Curve, and Knodel says the next part to camera himself. "We obviously were not willing to accept that, and so we started looking for ways to disprove it was actually registering the motion of the Earth."

He bought the instrument, ran the test, got a clean result, and immediately went looking for a way out of it.

How many people actually think this

YouGov asked Americans in April 2018. Eighty-four percent said they had always believed the world is round. Two percent said flat. Another five percent said they had always thought it was round but had started having doubts. The 18 to 24 group were likelier than anyone else to pick flat, at four percent.

Be careful with numbers that small. Two percent of an online panel is not many people, and a few of them are messing about, because the bottom couple of percent of any survey will agree to almost anything. The five percent who say something they used to be sure of has started to wobble is the figure worth watching.

Nobody in the Middle Ages thought this

The usual assumption is that flat earth is a leftover, some old idea we never quite finished clearing up. It isn't.

Aristotle had it sorted by about 350 BCE, and not with anything complicated. During a lunar eclipse the shadow the Earth throws on the moon is always a circle, and a sphere is the only shape that manages that from every angle. A century or so later Eratosthenes measured the whole planet off the difference in shadow angles at two Egyptian cities on the same day, and got close enough that the argument ever since has been about how close.

Medieval scholars taught a round Earth as well. Columbus was not out there proving anything about the shape of it. He was after a route, and the row with his critics was over how far away Asia was, which they turned out to be right about. The bit everyone remembers, the churchmen warning him he would sail off the edge, was largely made up by Washington Irving in an 1828 book about Columbus. It stuck hard enough that a historian, Jeffrey Burton Russell, wrote a whole book in 1991 taking it apart.

So this is not something old. Somebody made it.

The man who started it

Summer of 1838, Cambridgeshire. Samuel Rowbotham went down to the Old Bedford River, six miles of straight, still water. He set a telescope eight inches above the surface and watched a rowing boat with a three foot flag row to the far end. On a globe, that flag should have dropped some eleven feet below his line of sight. He said he could see it the whole way.

He was wrong, for a dull reason. Cold water bends light downward and lets you see further than the geometry allows, worst of all right down near the surface, which is exactly where he had put his telescope.

The wrong answer is not really the problem though. What lasted was the way he got there. Rowbotham called his approach zetetic, from the Greek for asking, and published it under the name Parallax, as a pamphlet in 1849 and then a proper book, Zetetic Astronomy: Earth Not a Globe, in 1865. The idea underneath fits on a badge. Believe what you can see and test yourself, and treat anyone who tells you otherwise as somebody with a reason to want you fooled.

That is the part that survived. Not the map.

Somebody tested it properly in 1870

A Rowbotham follower called John Hampden put money on being able to repeat the Old Bedford result. Alfred Russel Wallace took the bet. Wallace is remembered for arriving at natural selection at the same time as Darwin, but what matters here is that he was a trained surveyor.

He ran his sight line thirteen feet up rather than eight inches, clear of most of the refraction, and planted a pole in the water at the halfway mark. Over something flat, the middle pole and the far marker line up. Over something curved, the middle pole sits higher, because it is on top of the bulge. It sat higher, and the judge gave it to Wallace.

Hampden would not have it. He accused Wallace of cheating in print, took him to court, and got the wager thrown out so that Wallace had to hand the money back. He ended up in prison, for libel and for threatening to kill him. Wallace spent something like fifteen years dealing with the consequences of winning.

What YouTube did

The organised version stayed small for decades. Samuel Shenton set up the International Flat Earth Research Society in Dover in 1956, Charles Johnson ran it out of California from the early seventies, and by the late nineties it had a reported 3,500 members. That is a club.

Then Asheley Landrum, a psychologist at Texas Tech, went to the Flat Earth International Conference in 2017 and asked thirty attendees how they got there. Twenty-nine said YouTube. Hardly any had gone looking for it. They had been watching videos about other things, September 11, the moon landings, school shootings, and the sidebar offered up Mark Sargent's Flat Earth Clues or Eric Dubay's 200 Proofs the Earth Is Not a Spinning Ball, and they clicked. The thirtieth got it from family, who had found it on YouTube.

Nobody planned this. A system rewarded for keeping people watching worked out that somebody who will sit through one long video about a cover-up will sit through the next one, and it had no view at all on which cover-ups were real.

Why proof doesn't work

The proof is not hard to come by. Stand on a beach and watch a ship's hull go under before its mast does. Fly far enough south and there are stars over your head that were never above your old horizon. Aristotle's eclipse argument costs nothing to check the next time the moon goes dark.

None of it lands, and it is not because people are stupid.

To hold the flat model at all, you have already had to accept that a very large number of people are lying together and keeping it up: every space agency, every pilot flying a polar route, every ship's navigator, every physics teacher who ever drew the diagram on a board. Once a lie that size is in place, new evidence stops behaving like evidence. It turns into one more thing the liars must have arranged. Every fact you bring makes the conspiracy bigger, and to somebody already inside it, a bigger conspiracy is more convincing rather than less.

Which is why arguing about the shape is arguing about the wrong thing. Almost nobody gets here through astronomy. They get here because they stopped believing the people who explain things to them, and the planet is simply the largest object available to say that about.

Why it matters when it is only two percent

On its own it does very little harm. Planes land, ships arrive, and every phone at that conference ran GPS all weekend.

The habit travels, though. The same sidebar and the same do your own research instinct end up pointed at measles, at cancer treatment, at whether to take the storm warning seriously, and there it costs people.

Laughing is the one response guaranteed to fail, because being laughed at by people with qualifications is already part of the evidence. Landrum's own suggestion, after sitting with thirty of them, was that scientists ought to be making videos on the same platform instead of writing the audience off.

Behind the Curve ends with a different experiment. Jeran Campanella cut a hole in each of two boards at the same height, put a light behind them at that same height, and set a camera up on the far side. If the ground is flat, the beam goes through both holes and into the lens. He switched it on. Nothing came through.

Someone off camera, one of his own people, told him to lift the light. Way above your head. He lifted it, and there it was, at about the height you would need to clear the curve.

Campanella looked at it for a second.

"Interesting," he said. "That's interesting."

The film stops there. He had designed the test himself, run it honestly, and watched it come back with the answer he did not want, and what he does in the next second is the whole question. Hampden got that answer in 1870 and spent the next decade in court. Knodel got it out of a $20,000 gyroscope and went hunting for a way round it. None of these people are short of curiosity, or effort, or the willingness to go and build the thing. What they have run out of is any reason to believe an answer when it finally turns up.

Sources

• YouGov, "Most flat earthers consider themselves very religious" (the April 2018 poll: 84 percent firmly round, 2 percent flat, 5 percent with recent doubts, and the 18 to 24 breakdown).
• Wikipedia, "Bedford Level experiment" (Rowbotham's 1838 setup, the eleven foot expected drop, and Wallace's 1870 repeat).
• Wikipedia, "Samuel Rowbotham" (the Parallax pen name, the zetetic method, the 1849 pamphlet and 1865 book).
• Wikipedia, "Alfred Russel Wallace" (his surveying background, and the litigation and threats that followed the wager).
• Wikipedia, "Flat Earth Society" (Shenton's 1956 founding in Dover, Johnson's California presidency, the reported 3,500 members).
• Wikipedia, "Myth of the flat Earth" (how Washington Irving's 1828 Columbus biography manufactured the medieval story).
• Wikipedia, "Inventing the Flat Earth" (Jeffrey Burton Russell's 1991 account of where that myth came from).
• Wikipedia, "Eratosthenes" (the circumference measurement of around 240 BCE and the dispute over its accuracy).
• The Guardian, "Study blames YouTube for rise in number of flat earthers" (Landrum's conference interviews, the 29 of 30 figure, and her suggestion that scientists engage on the platform).
• Newsweek, "Flat Earthers Disprove Themselves in 'Behind the Curve'" (Knodel's $20,000 gyroscope, the fifteen degree per hour drift and his quoted response, and Campanella's closing light experiment).
• Wikipedia, "Modern flat Earth beliefs" (background on the contemporary movement and its arguments).