Ultra Wide-Angle Lens

An ultra wide-angle lens produces images with an extremely wide angle of view. A lens with a focal length shorter than 24 mm (full-frame equivalent) is considered an ultra wide-angle lens. Ultra wide-angle lenses come in two varieties: rectilinear lens and curvilinear, or fisheye lens.

Because of their wide field of view, Earth’s curvature is easier to observe using an ultra-wide lens. Flat-Earthers incorrectly assumed it means a fisheye lens that distorts straight lines. In reality, there are rectilinear ultra wide-angle lenses that preserve straight lines. With these lenses, if the horizon looks curved, then it must be due to Earth’s curvature itself.

Continue reading “Ultra Wide-Angle Lens”

Fallacy of Overprecision

The fallacy of overprecision occurs when an overly precise number is used to give the appearance of truth and certainty.

Some prominent flat-Earthers like to use overly precise long digits of numbers to give the bogus impression of science. And those susceptible to believing a flat Earth tend to be intimidated by math, and it is easy to awe them with meaningless numbers.

Continue reading “Fallacy of Overprecision”

Zooming-In on the Setting Sun

Featured Video Play Icon

Camera zoom works by enlarging the center portion of the image, or in other words, by making its field-of-view narrower. Zooming in on the setting sun will not reveal more of the sun and will only enlarge the size of the sun in the resulting image.

Flat-Earthers claim that zooming in on a setting sun will reveal the full sun and somehow lift it out of the water. In reality, they used incorrect exposure settings, making the sun still above the horizon appear already half-obscured by Earth’s curvature.

Zooming on the setting sun will never reveal the sun already obstructed by Earth’s curvature.

Continue reading “Zooming-In on the Setting Sun”

Conspiracy Theories are Immune to Evidence

Conspiracy theories are immune to evidence. They are inherently self-sealing. Evidence that disproves a conspiracy theory is reinterpreted as originating from the conspiracy.

When faced with evidence that disproves flat Earth, rather than considering the evidence, flat-Earthers will simply invent an “explanation” that the evidence was fabricated by those in the conspiracy & include those who told them the evidence as being part of the conspiracy. Sometimes even evidence that can be personally verified also gets the same treatment.

Continue reading “Conspiracy Theories are Immune to Evidence”

GoFast Rocket and Yo-Yo De-Spin Mechanism

Featured Video Play Icon

The GoFast rocket is considered to be the first amateur rocket to reach space, beyond the Kármán line. The rocket was spin-stabilized through ascent. After reaching a certain altitude, it used the yo-yo de-spin mechanism to reduce the spin rate.

Flat-Earthers noticed the rocket’s spinning motion suddenly slowed, and they used it to “prove” the rocket “hit a barrier” up there. In reality, a yo-yo de-spin mechanism was deployed to slow the spin, but the rocket was still going up for some time afterward. — Hitting a barrier would have destroyed the rocket.

Continue reading “GoFast Rocket and Yo-Yo De-Spin Mechanism”

Defishing Fisheye Images Excessively to Flatten the Curved Horizon

Defishing is a process for removing barrel distortions from fisheye images, producing rectilinear images that preserve straight lines. A different fisheye lens produces a different amount of distortion & needs a different defishing strength.

Flat-Earthers like to apply a stronger defishing parameter than necessary with the goal not to remove the distortions but to make the horizon flat. As a result, they not only remove barrel distortion from the image but also introduce pincushion distortion that straightens the curved horizon.

The horizon in the end image might appear flat. However, it is due to the distortion these flat-Earthers deliberately introduced to the image, not because the horizon is flat.

Continue reading “Defishing Fisheye Images Excessively to Flatten the Curved Horizon”

Google Street View

Flat-Earthers noticed “mysterious” wandering vehicles with a Google branding and strange equipment mounted on them. They use the fact as “evidence” that Google Maps does not use satellites to obtain the images. In reality, these vehicles record images for Google Street View. It is impossible for street-level
vehicles to obtain the aerial images used by Google Maps.

Continue reading “Google Street View”

The “Earth is a Realm” Quote Misattributed to Nikola Tesla

The “Earth is a realm” quote is often wrongly attributed to Nikola Tesla in flat-Earth communities and incorrectly regarded as “evidence” that Tesla believed Earth is flat.

Someone wrote pseudoscientific drivel and added an actual quote by Nikola Tesla. Flat-Earthers wrongly assume both statements are by Tesla & it became a hoax claiming Tesla was a flat-Earther.

The quote by Tesla was taken from “The Problem of Increasing Human Energy,” in which Tesla mentioned the word “globe” 12×, “gravity” 4×, “planet” 10×. It is clear Tesla was not a flat-Earther.

Continue reading “The “Earth is a Realm” Quote Misattributed to Nikola Tesla”

Cellular Network Backhaul

In cellular telecommunications, backhaul is the connection between a base transceiver station and the core network. The means of the connection can be anything, including cable, fiber optic, microwave links, and satellite links.

Flat-Earthers use the fact that cell phones communicate with base stations as “evidence” satellites do not exist. In reality, some cellular companies do utilize a satellite for backhaul purposes, especially for stations in remote, isolated areas.

Continue reading “Cellular Network Backhaul”

Bokeh

In photography, bokeh is the way a lens renders out-of-focus points of light. The shape of bokeh depends on the shape of the lens’s aperture more than the out-of-focus objects themselves.

Flat-Earthers fail to take properly-focused photos of stars and planets because of their lack of photography skills and because their cameras are not suitable for the purpose. They are just getting bokeh, which tells us more about their equipment (and lack of knowledge) than the actual intended objects.

Continue reading “Bokeh”

First Image of Earth From Space Taken By a V-2 Rocket

The first image of Earth from space was taken by the V-2 No. 13 rocket in 1946 using the DeFry 35mm movie film camera and a 50mm lens attached to the rocket. The camera had a relatively narrow field of view. As a result, Earth’s curvature is only very slightly visible.

Flat-Earthers claim the flat appearance in the photo “proves” a flat Earth. In reality, 1. by careful examination, we can see the curve, 2. the camera has a narrow field of view, reducing the visible curvature, 3. the photo shown by flat-Earthers is usually a cropped version, further reducing the visible curve, and 4. the photo matches the expected curvature according to simulation.

Continue reading “First Image of Earth From Space Taken By a V-2 Rocket”

Theories of Gravity

Gravity is a natural phenomenon by which all things with mass or energy are brought toward one another. Today, gravity is explained by two theories: Newton’s law of universal gravitation and Einstein’s general relativity.

Flat-Earthers treat the existence of the two theories as a supposed conflict, and they use it as “evidence” of wrongdoing. In reality, these are two separate theories that explain the phenomenon of gravity. Einstein’s is more accurate yet more complex. In contrast, Newton’s is simpler but less accurate. Despite having been superseded, Newton’s gravity continues to be used as an excellent approximation of the effect of gravity in most applications.

Continue reading “Theories of Gravity”

The Wallace Method

In 1870, Alfred Russel Wallace proved Earth’s curvature in the Bedford level experiment. His method was straightforward & effective and can be easily used in a similar experiment.

Wallace’s method fixes the common issues with similar experiments done by flat-Earthers. They usually fail to control, and even disregard, the effect of atmospheric refraction. Using Wallace’s simple method, we can easily prove Earth is a sphere.

Continue reading “The Wallace Method”

Magnitude of Visible Earth’s Curvature in a Photograph

The magnitude of the curvature that appears in a photograph of Earth’s curvature depends on several factors:

  1. The observer’s altitude.
  2. The camera’s field of view or focal length.
  3. The distortion characteristics of the camera lens.

Flat-Earthers like to dismiss a photo of Earth’s curvature by comparing it to another photo showing a different amount of curvature. In reality, to compare the visible curvature, we need to ensure all the images were taken from the same altitude, same field of view, and account for the lens’ distortion.

Continue reading “Magnitude of Visible Earth’s Curvature in a Photograph”

Unhealthy Skepticism

Flat-Earthers like to employ an extreme, unhealthy “skepticism” toward scientific concepts. We can demonstrate its absurdity by applying the same level of unhealthy “skepticism” toward everyday things that we have taken for granted. We would not be able to know these things and cease to function like normal humans.

Continue reading “Unhealthy Skepticism”

Danyang–Kunshan Grand Bridge

As of 2021, the Danyang–Kunshan Grand Bridge is considered the longest bridge in the world. It is a 164.8-km-long viaduct bridge in China, consisting of 2000 spans of ~80 m long each. Like every other bridge, it is constructed following Earth’s curvature.

A hoax in flat Earth communities claims the Danyang–Kunshan Grand Bridge somehow “proves” flat Earth. In reality, it is just a claim asserted without evidence and then spread as a hoax.

The bridge is a viaduct with many short spans, and therefore, accounting for Earth’s curve is less critical than in the case of longer-spanning bridges. Nevertheless, it is still built to follow Earth’s curvature.

Continue reading “Danyang–Kunshan Grand Bridge”

Perth–Johannesburg Flight Route

Featured Video Play Icon

By comparing the duration of the non-stop Perth–Johannesburg flight route with the same route with a stop, we can conclude the route is only possible if Earth is a sphere.

There are other Perth–Johannesburg flights but with a stop, like in Dubai. Flat-Earthers use it to “prove” a flat Earth. In reality, it does not mean the non-stop route does not exist. And it is easy to verify the existence of the non-stop route. These are consistent only with a spherical Earth and can never be explained if the Earth is flat.

Continue reading “Perth–Johannesburg Flight Route”

Cost of the Apollo Lunar Roving Vehicle (LRV)

The Apollo Lunar Roving Vehicle (LRV) cost $38 million, equivalent to $260 million in 2021. Flat-Earthers claim the cost was too much for such a “dune buggy” & use it to discredit the Apollo mission. In reality, the cost was reasonable for such a project.

Continue reading “Cost of the Apollo Lunar Roving Vehicle (LRV)”

Quote Mining

Quote-mining is the fallacious tactic of taking quotes out of context to make them seemingly agree with one’s position.

Quote-mining is a common flat-Earthers’ tactic. They take statements from scientists, pick a small part, and remove the surrounding context. The information no longer resembles the initial meaning, but then it is attributed to the original author or speaker to exploit or discredit their names and reputations.

Continue reading “Quote Mining”

Big Diomede and Little Diomede Islands

Featured Video Play Icon

The Big Diomede and Little Diomede are islands in the middle of the Bering Strait. Although only 4 km apart, they belong to different countries and have a 21-hours time zone difference.

Flat-Earthers noticed the number of polar days is different on both islands during the summer solstice & they used it to discredit science. In reality, the islands are very close to the Arctic circle, & during the June solstice, the sun’s path is almost parallel to the horizon. A tiny change in latitude or height can result in a large change in sunrise & sunset times.

Continue reading “Big Diomede and Little Diomede Islands”