First published September 30, 2022.
No, the Earth is not shaped like a doughnut. The idea comes from a user called Varuag on a flat-Earth discussion forum, who suggested that our planet might be a torus and that bent light hides the hole in the middle from view. It is a fun thought experiment, but the physics behind it does not hold up, and the way the theory protects itself is a textbook lesson in how not to test an idea.
Below is what the post actually proposed, why light does not behave the way it claims, how we know the real shape of the Earth, and why a story that adds a new excuse for every problem stops being an explanation at all.
What the doughnut-Earth post proposed
The post, which was picked up and shared widely on 9GAG, started with a reflection rather than a claim. Varuag wondered how something like flat-Earth theory gets built in the first place, and guessed that it begins with one person's idea, followed by a long chain of critics pointing out holes and believers patching them.
Then came the twist. In the user's own words: "I have a theory that the Earth is in fact shaped like a torus (a donut-shape)."
To explain why nobody sees a giant ring curving up into the sky, the post leaned on light. According to Varuag, light fades as it travels; once it is weak enough it bounces off the atmosphere, then bounces again, and again, curving each time. That chain of reflections would supposedly make the ground look flat, or only gently curved.
When other users asked the obvious question, why we cannot look up and see the far side of the ring, the answer added another layer. Light heading upward would pass out through our part of the atmosphere, reach the atmosphere on the other side of the hole, be too weak to get through, and bounce away into space. So we would see only the night sky.
Whether the poster was serious, joking or testing how a fringe theory grows is hard to tell from a few paragraphs. Older headlines described Varuag as a "leading member" of the Flat Earth Society, but nothing in the original thread showed any official role. The fairest reading is that it was one forum contributor floating an idea, and the most interesting thing about it is the structure of the argument.
Why light does not bounce around the sky like that
The post builds its case on a real phenomenon. Some radio signals really do come back down after hitting the upper atmosphere. This is called skywave propagation, and it is how shortwave broadcasts can cross oceans. It works mainly for high-frequency radio, roughly 3 to 30 MHz, which is bent back by the ionosphere, an electrically charged layer that sits about 80 to 1,000 kilometres up.
Higher frequencies behave differently. Above about 30 MHz, most radio waves pass straight through the ionosphere instead of returning, which is why FM radio and TV need line-of-sight towers. Visible light has a frequency millions of times higher still, and it sails through the atmosphere. That is the reason we can see the Sun, the Moon and the stars at all.
The idea that light "diminishes" until it is weak enough to be reflected also gets things backwards. A dimmer beam of light is made of fewer photons, not different ones. Whether light is reflected or transmitted depends on its wavelength and the material it meets, not on how bright it is.
Light does bend a little in air. Atmospheric refraction lifts objects near the horizon by about 34 arcminutes, a little more than the width of the Sun, and it produces mirages over hot roads or cold seas. Surveyors and astronomers correct for it every day. But it is a small, measurable effect, and it points in a known direction. It cannot hide a hole thousands of kilometres wide.
How we know the Earth is round
Greek philosophers were writing about a spherical Earth by the 5th century BC, and by the 3rd century BC astronomers were already estimating its circumference. The clues they used are still easy to check:
- Lunar eclipses. The shadow the Earth casts on the Moon is always curved, whatever the angle. Only a sphere does that every time.
- Changing stars. Travel north or south and different constellations rise or disappear. The Pole Star sinks toward the horizon as you head toward the equator.
- Ships and coastlines. Distant ships and shorelines vanish from the bottom up, and climbing higher lets you see further.
- Circumnavigation. The Magellan–Elcano expedition of 1519 to 1522 sailed west and came home from the east.
- The view from above. Aircraft, satellites, the International Space Station and countless photographs show a curved horizon and a round planet.
Measurement has gone further than "round". Isaac Newton argued that a spinning Earth should bulge at the equator, and modern geodesy confirms it: the planet is very slightly flattened, by about 1 part in 298. GPS, satellite navigation and long-haul flight routes all depend on that precise shape.
Could a doughnut-shaped planet exist at all?
Here the forum post accidentally touches on real science. Physicists have asked whether a ring-shaped world is possible, and the study of rotating fluid tori goes back to Henri Poincaré and Sofia Kovalevskaya in the 1880s. A spinning torus can, in principle, hold together if it rotates fast enough for its spin to balance its own gravity.
The catch is stability. Work by Frank Dyson in 1893 showed that such a ring tends to break into "beads", thicker in some places than others, and later researchers found similar problems. No torus-shaped planet has ever been observed, and there is no accepted way for one to form naturally.
The closest real thing is a synestia, a short-lived, doughnut-like cloud of vaporised rock that scientists Simon Lock and Sarah Stewart proposed may have formed after the giant impact that created the Moon. It is a stage in a collision, not a home for oceans and cities.
Even if a ring planet existed, it would be obvious to the people living on it. Gravity would pull in different directions near the inner rim, the sky would show a huge arc across it, and the stars would move in ways nothing like what we actually see.
The real lesson: ideas that cannot fail
The most useful part of the doughnut post is the pattern it shows. First comes a bold claim. Then an obvious objection arrives, and instead of the claim being tested, a new mechanism is invented to explain the problem away. Then another objection, and another invisible mechanism.
Philosophers of science have a name for these patches: ad hoc hypotheses. They are added after the fact for one reason only, to shield an idea from evidence. Karl Popper, in his 1934 book on scientific method, argued that a good scientific claim must stick its neck out. It should forbid certain observations, so that if we see them, the claim is in trouble.
The torus theory forbids nothing. If the ground looks flat, bent light did it. If the sky looks empty, bent light did it again. A theory that is compatible with every possible observation tells us nothing about the world. Its flexibility looks like strength, but it is actually emptiness.
That test works well beyond science. When you hear a claim, ask: what would convince the person making it that they are wrong? If the honest answer is "nothing", you are dealing with a belief, not an explanation.
Where the Flat Earth Society comes from
Modern flat-Earth organising has a surprisingly specific history. Samuel Shenton founded the International Flat Earth Research Society in Dover, England, in 1956. After his death in 1971, Charles K. Johnson took it over from California, and membership reportedly grew to a few thousand before a 1997 fire destroyed its records. Johnson died in 2001.
In 2004 Daniel Shenton, no relation to Samuel, revived the group as an online forum, relaunched it with a website in 2009, and saw part of the community split off in 2013 to form a separate forum. Today believers disagree even among themselves: most favour a disc, some an endless plane under a dome, and a few have floated other shapes entirely. A torus fits naturally into that pattern of competing private models.
Myths about flat Earth beliefs
"People in the Middle Ages thought the Earth was flat"
They did not, at least not educated ones. Historians agree that scarcely any medieval scholar doubted a spherical Earth. The myth was popularised in the 19th century, partly by Washington Irving's romanticised 1828 biography of Columbus, which invented a scene of churchmen objecting to a round world. The real argument in Columbus's time was about the size of the Earth and the distance to Asia, and his critics were closer to the truth.
"Flat-Earth groups all agree on one model"
They do not. As the doughnut idea shows, alternative models multiply because none of them has to match careful measurements. The scientific picture, by contrast, converges: every independent method gives the same shape.
"You need special equipment to check the shape of the Earth"
You do not. Watching a lunar eclipse, comparing sunset times with a friend in another city, or noting which stars you can see on a trip south are all things anyone can do.
The kindest response to a theory like this is curiosity rather than mockery. Asking what it predicts, and checking those predictions, is how the shape of the Earth was worked out in the first place.
Sources: 9GAG (original post shared by Varuag); Wikipedia: Skywave; Wikipedia: Atmospheric refraction; Wikipedia: Spherical Earth; Wikipedia: Toroidal planet; Wikipedia: Falsifiability; Wikipedia: Flat Earth Society; Wikipedia: Myth of the flat Earth
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