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The story
An article reporting that 16% of US adults don’t agree the Earth is round drew a wave of responses on 5ch’s Science News+ board. While some pointed to religion or poverty as underlying factors, the thread evolved into a debate over ways to verify the Earth’s roundness for yourself — from watching ships vanish over the horizon to laser experiments.
16% of US Adults Don’t Agree the Earth Is Round… The Background Behind Why the Crackpot “Flat Earth” Theory Persists
Kazushi Matsumura, Associate Professor, Graduate School of Human Sciences, Osaka University
That the Earth is round seems like an unquestionable fact of common sense.
Source: president.jp / Original article here
What people said
Guess it just shows how unequal the society is, with a fixed chunk of people at the extremes.
It's about religion, not because they're poor.
That game's world really is basically flat-earth central.
Play Animal Crossing and you'll believe it's a sphere.
Try climbing up to about height 128 in Minecraft.
The world's super round.
You're all just holograms.
Something like 'don't just feed me𓃠 🐙octopus, eat 🦑squid too' and '🦇🦇bats, not 🦟mosquitoes'
Don't really get it
Duh-earf iz rownd (deliberately garbled, mocking spelling — 地球/'Earth' swapped for a pun meaning 'idiot-level')
Set them up at points A and B, 10km apart.
Fire a laser through the hole in the board at point A.
Since light travels in a straight line, if flat-earth theory were true, the laser from point A should pass through the hole in the board at point B.
But in reality, the laser never passes through the hole at point B — it hits a spot above the hole, offset upward.
In other words, this proves the Earth isn't flat, it's a sphere.
Do this experiment and you'll get it in seconds.
> the laser hits a spot above the hole, offset upward
If you space them 10km apart, the laser won't even hit unless the boards are ridiculously huge.
You don't even need a laser — just measure the shadow length of identical sticks at distant points at the same time.
Must be rough, but hang in there and keep on living… sheesh.
> oblate spheroid
To be even more precise, it's shaped more like a pear.
It's already too late for you…
You can't deny it, right? Both you and I are beings controlled by a game system — just characters inside some advanced SimCity.
Your parents must be going through hell…
Can't confirm it either.
Things you can neither confirm nor deny are basically just delusion.
Religion included.
Keep walking straight and you'll end up back where you started.
Probably just never leaving their village.
Even the land survey map of my own property doesn't show any elevation difference proving the Earth is a sphere.
Go to the coast and watch a ship approach!
I was born in a coastal town, so I've seen ships sink below the horizon plenty of times since I was a kid.
Maybe try drawing a perspective diagram.
There's a thing called a vanishing point.
The logic should be that it becomes a point on the horizon.
In other words, even when drawing that ship, you never factor in any number for the Earth being round.
Even a 10m object shrinks to a point and eventually disappears.
But that's still just it vanishing on flat ground's horizon, nothing more.
Can't give a reason?
This kind of thing has got to be partly about your attitude toward knowledge.
Personally, I consider anything I can't confirm myself as objective fact to be pure subjectivity.
I've never confirmed with my own power, without special equipment, that the Earth is round.
So I can't bring myself to criticize people who think it's flat.
'I only believe what I've confirmed myself' basically means you can't learn from anyone else's knowledge.
At the end of the day that's just dressing up an excuse to believe misinformation.
You can tell it's a sphere from watching ships vanish over the horizon, or from the round shadow on the moon during a lunar eclipse, right?
If that's how you think, didn't you ever look into it as a kid?
That's just how I see things, can't help it.
I make a point of treating only what I can confirm myself as objective fact.
That doesn't really cause me any problems.
I just don't casually believe things I can't verify with my own hands.
For what it's worth, I've studied science, so I'm good at drawing accurate diagrams.
Not illustrations — diagrams.
So I have more ability than the average person to read and represent objects scientifically.
But I've never once actually seen the numbers that show the Earth is round.
Apparently that's now considered wrong.
Turns out there's ice, not water, they say.
But since I can't confirm it myself, I can't judge which is correct.
Sure, people who blindly believe what others say without scientific verification are fools.
But have you all actually verified with your own experiments that the Earth is a sphere?
Or are you just believing what other people tell you?
Huh, doesn't that make you no different from the fools you're mocking!
Here's an experiment anyone can use to verify the Earth is round.
If it's a sphere, then the water's surface is curved too, not flat.
So look across a body of water more than 5km wide and see if you can spot the far shore.
If it's curved, you shouldn't be able to see the low shoreline — only the tops of tall buildings.
5km is the distance at which, given Earth's diameter, the far side disappears below the sea surface.
Do this and you too are a proper scientist.
By the way, here's a photo from when I actually ran the experiment.
https://media.wired.jp/photos/65ffee09c971dd1c60869ff1/master/w_1600,c_limit/science-pontchartrain-(1).jpg
Background and Key Points
The number the article cites echoes a genre of English-language polling from the past decade — YouGov-style surveys that ask Americans whether they’ve “always believed,” “used to believe but now doubt,” or “never believed” the Earth is round, with the flat-Earth-adjacent minority landing somewhere around one in six. That movement itself is not new: it traces to the 19th-century “Zetetic” society founded by Samuel Rowbotham, and was revived in the 2010s largely through YouTube and podcast conspiracy culture, often overlapping with distrust of NASA, biblical literalism, and general institutional skepticism — the “religion, not poverty” framing raised early in the thread is closer to the actual research literature than the “unequal society” theory it was responding to.
What the thread actually divided over wasn’t belief versus disbelief in a round Earth — nobody on 5ch endorsed flat-Earth theory outright — but a meta-question: what counts as legitimate proof, and who gets to claim they’ve “verified” anything themselves. Posters proposing horizon, laser, and shadow experiments were met not by flat-Earth pushback but by a self-described empiricist arguing that trusting textbook diagrams is itself just secondhand belief, no different in kind from religious faith. That argument, and the pushback that refusing all secondhand knowledge makes learning from anyone impossible, is the real fault line here.
The thing likely to be missed by readers unfamiliar with the source: a “don’t fully agree the Earth is round” response in polling isn’t the same as “believes the Earth is flat” — it usually captures agnosticism or reflexive contrarianism toward a question people rarely think about, not a coherent competing cosmology.
*This article is excerpted and summarized from the 5ch (Science News+) thread “[Pseudoscience] 16% of US Adults Don’t Agree the Earth Is Round… The Background Behind Why the Crackpot “Flat Earth” Theory Persists”.
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