When you Google “How to prove earth is round,” this article comes up first. It’s a roundup of globe earth talking points.
Many post it when they encounter Flat Earth, and think their work is done. But all the points are based on assumptions and easily debunked. Let’s go through them one by one.
1) The Moon.
The author states eclipses are caused by earth’s shadow. We have no evidence that shadows affect the moon.
The sun and moon sometimes appear simultaneously during an eclipse. This is called a selenelion. It proves that not all three bodies are lined up in a row. This would be necessary for a shadow to cause an eclipse. We don’t know what causes lunar eclipses, but it’s not earth’s shadow.
1b) Foucault’s Pendulum.
Foucault’s pendulum doesn’t prove earth is moving. A pendulum can swing in any direction, depending on the force acted on it. It requires an electrically powered magnetic source to keep it in motion. If the earth were really moving, no pendulum anywhere would be motionless!
2) Ships and the Horizon.
We encounter this argument a lot, and it’s an ancient one. When globers see a ship disappearing on the horizon, they were taught to believe it’s the ship going over the curve. There’s a couple of problems with this.
First, we observe no curvature on the horizon of the ocean. The line where the ocean appears to meet the sky is the X axis, if you will. It’s always a perfectly straight line with no curve.
So, if there were a curve between the observer and the horizon, that would mean the ocean is shaped like a cylinder.
And no one is saying it’s a cylinder. I hope.
The second problem with the “ship goes over the curve” argument is that ships, when they disappear behind the line of convergence, can be brought back into view with a zoom lens. If they had gone behind a hill of water, no zoom lens could bring them back.
2b) Ant and Orange.
The idea is that if you were observing an ant walking towards you on an orange, you would see his antennae come up over the edge, then his head, body, and legs. This phenomenon of seeing the ant’s body in stages would occur on a flat surface as well, if the ant were able to approach you from the point where he had disappeared into the line of convergence. Also, the relative size of an ant vs. an orange is not comparable to that of a ship vs. the ocean, so the point is moot anyway.
The article states that Aristotle noticed different constellations are visible from different regions, and he concluded that earth is a ball. If that’s true, Aristotle didn’t think about it very much.
We see different constellations in different regions because the celestial dome has different stars in different areas. Some are invisible from some locations because of perspective. For example, you can’t see Polaris from Australia. But you can see The Big Dipper from northern Australia, which would be impossible if the earth were a globe.
4) Sticks and Shadows.
This beloved talking anecdote is based on an experiment supposedly done by Eratosthenes, the ancient Greek astronomer. Trouble is, there’s no evidence of his work, and all the records were destroyed when the library in Alexandria burned.
So, even if I’m being generous, and assume Eratosthenes did an experiment where he calculated the circumference of the earth, his numbers were wrong, and likewise his conclusions. If sticks demonstrate different shadow lengths, it’s because of the movement of the sun, not the curve of the earth.
5) Seeing Farther from Higher.
Being able to see farther from higher would be true whether earth is curved or flat, so this doesn’t prove either shape. However, the horizon continues to rise to eye level, no matter how high you go, which could not happen on a globe. If the earth were a globe, the horizon would curve down and away from the observer, and could never form a straight line at a high altitude.
The author’s argument on airplanes is twofold: 1) that an airplane can go a long distance without falling off the edge, and 2) that you can see the curve of the earth from an airplane. I think it was late and the author was getting tired.
Airplanes can go a long distance before they reach the edge, that is, unless they’re heading due South. At some point they will reach the southern latitudes and travel is regulated by the Antarctic Treaty. But planes can and do circumnavigate the earth East to West, in the style of Magellan.
As for the curve of earth, no one has seen it from an airplane, unless they were looking through a curved window, or using a fisheye lens (a type of wide-angle lens that can cause distortion).
7) Other planets.
I’ve written about this before, and since all we think we know about “other planets” comes from NASA’s CGI and artist’s renderings, this isn’t a valid proof of round earth at all. What they call planets are wandering stars, lights in the firmament. We have no proof that they are spheres, just that they are round.
8) Time Zones.
Time zones are a great Flat Earth proof since they are caused by the sun travelling over our stationary plane, casting light in different areas as it goes. If earth were a globe, exactly one half of the world would be in darkness at all times. That is not what we experience.
This section is meaningless because it relies on the assumption that gravity exists. Assumptions are meaningless (h/t @rokro11). Gravity is only required to explain how objects of great mass would be attracted to each other, or spin, or orbit; but since all those are assumptions gravity is not required.
10) Images of Space.
I notice the author saves this til her last point, hoping most people have gotten bored and stopped reading by now. Because images of space are fake and easily debunked. NASA admits that all their images are composites, i.e., Photoshopped. My favorite is the grey refrigerator magnet. I think it’s supposed to be the moon.
Thanks for reading! Stacey