A Glass of Water

The surface of the water in a glass of water is practically flat. Some flat-Earthers claim this is ‘evidence’ that the surface of the water is flat, and it will always be flat no matter how wide the container. They are wrong.

If the Earth is a sphere with the radius of 6371 km (3960 miles), then the surface of the water in a 10 cm (4 in) wide glass will have a bulge of 0.00000002 cm as the result of gravity, excluding other effects like the surface tension.

Grid Corrections — How the Spherical Figure of the Earth Affects Land Partitioning

Some countries decided to partition their territories into a rectangular or square grid. But the Earth is spherical, and it is not possible to divide a spherical surface into a perfect rectangular grid while maintaining the perfect angles, distances, and areas.

To solve this problem, land surveyors implemented grid corrections. Every certain distance, parts of the grid are shifted away from each other. Therefore, an equal area in each division is maintained as much as possible by giving up an entirely lined up grid.

If the Earth is flat, it is not necessary to have this compromise. It would be possible to divide the land into a perfect square grid system.

“Earth is a Sphere” Semantic Games

The Earth is spherical, but not perfectly spherical. Its diameter is longer across the equator than between both poles. The shape is called ‘oblate spheroid’. The difference between both diameters is tiny, only about 0.33%. It is perfectly fine to say that the Earth is round or spherical.

Some flat-Earthers take this issue very seriously. They think if that’s the case, then we can’t say the Earth is spherical. They are wrong. If we can’t say the Earth is a sphere, then we can’t describe every other spherical object as spherical, because nothing is perfectly spherical.

The Distance to Polaris

Anyone who is in the northern hemisphere can observe the star Polaris, located very close to the north celestial pole. As a result, when observed casually, Polaris appears practically stationary in the same position.

Flat-Earthers claim that the fact Polaris appears stationary as ‘evidence’ that the Earth is stationary: if the Earth is in motion, then Polaris should appear in motion too. They are wrong. Polaris appears stationary because it is very far and its motion can’t be visually observed in the scale of a human life.

The Fallacy of Statement of Conversion

The fallacy of statement of conversion is committed when someone is taking a statement of conversion as valid without actually hearing a reason for the conversion.

Flat-Earthers often tell others that they used to believe the Earth is a globe, but now they ‘know better’ and believe in a flat-Earth. All this only tells us they changed their mind. Accepting this as proof of a flat-Earth would be committing the fallacy of statement of conversion.

Observing Mercury and Venus

Mercury and Venus are closer to the Sun compared to the Earth. The best condition to observe these planets is during some time after sunset or before sunrise. In some cases, they are even visible in the day.

Many flat-Earthers think that it should be impossible to observe Mercury & Venus as they are closer to the Sun. They are wrong.

Evidence of Curvature: Turning Torso Building, Malmö, Sweden

Turning Torso is a 190 m (623 ft) high building in Malmö, Sweden. It is situated near the strait of Øresund. At the other side of the channel lies the city of Copenhagen, Denmark, only 15 km (9 miles) away from Malmö. Turning Torso has a distinctive segmented shape that is easy to recognize from far. And more importantly for our purposes, the segmented form is making it easy to judge its height from far.

Apollo Mission Profile

The Apollo missions really happened and humans have actually visited the Moon. If someone fell victim to the flat-Earth conspiracy, then it would imply that they also fell victim to the Apollo moon landing conspiracy. But they are wrong.

Someone usually fell for the moon landing conspiracy theory because of emotional appeals and confirmation bias, but also because of their ignorance of the Apollo mission profile itself.

The following is a very brief description of the Apollo mission profile, numbered according to the numbers in the illustration.

Cognitive Dissonance

Cognitive dissonance is the mental discomfort experienced by a person who simultaneously holds two or more contradictory beliefs.

Cognitive dissonance often happens with devoted flat-Earthers when they are confronted with facts and evidence showing that the Earth is spherical. Continue reading “Cognitive Dissonance”

The Directions of Up and Down

The directions of up and down are determined from the direction of the Earth’s gravitational acceleration. Up is in the opposite direction, and down is in the same direction as the Earth’s gravitational acceleration.

Flat-Earthers are often seen making fun of this fact. They show us ‘upside down’ pictures taken in the southern hemisphere. They are wrong. To anyone in the southern hemisphere, down is in the same direction as the Earth ‘s gravitational acceleration, the same as anyone in the northern hemisphere.

Neil deGrasse Tyson and His ‘Pear-Shaped’ Analogy

In a talk show, Neil deGrasse Tyson explained the figure of the Earth. He told the audience that the Earth is practically round, but it is a little farther from the center near the equator compared to the poles. And that in the southern parts, it is a bit farther from the center than in its northern regions. To illustrate the fact, Neil used the analogy ‘pear-shaped.’

Flat-Earthers really love to ridicule the ‘pear-shaped’ analogy. But they are mistaken. If they watch the entire unaltered video, they will find Neil explained the fact very clearly.

How Satellites Can Orbit and Stay Up There

If Earth’s gravity pulls everything towards the Earth, then how can satellites stay up there and are not falling towards the Earth?

The answer is that satellites orbit the Earth. They have the correct velocity with respect to Earth’s position and gravitational pull.

The Cities of Punta Arenas, Dunedin, and Murmansk During the December Solstice

During the December solstice, on December 21, the Sun reaches its southernmost point. During this time, the northern parts of the Earth are experiencing the peak of winter, and conversely, the southern regions are experiencing the height of summer.

Most flat-Earth denominations picture the sun shining like a spotlight, and they can’t explain what is happening in the southern parts of the Earth during the December solstice.

The Reason We Cannot See Earth’s Curvature When Standing on a Beach

We can’t directly observe and subjectively perceive the curvature of the Earth from a position close to the surface. And this matches the expectations in the spherical Earth model.

Flat-Earthers often take the fact we can see the curvature by standing on a beach as ‘evidence’ the curve doesn’t exist. They are, once again, wrong.

Fisheye Lenses Can Make Curved Lines Appear Flat

A fisheye lens distorts images. It results in images having barrel distortions. In a fisheye lens, a straight line can appear curved. But some flat-Earthers don’t realize that the opposite is also true, a fisheye lens can easily make a curved line look straight.

The Non-Correlation Between Salinity and Tides

Seawater salinity does not have a correlation to tides. Just because seawater has a higher salinity than lake water, it does not mean salinity causes tide.

Some flat-Earthers claim tides are the result of salinity. They are wrong. There are bodies of water that do not have tides as large as seawater, but their salinity is much higher than seawater.

Contextualism and Flat Earth

Contextualism is treating what we know as context-sensitive. We can use the epistemic contextualism as a philosophical tool to explain the Earth is spherical, and bypass all the scientific explanations.

Flat-Earthers love to shift the context to where we would no longer function as a normal human being because only in this context, most of us cannot possibly know the shape of the Earth.

But in the context where we all act like normal human beings, there’s no problem to know the Earth is spherical, even if we don’t know all the scientific details.

Curvature Calculators and Atmospheric Refraction

Atmospheric refraction causes a distant object to appear higher than its actual position. As a result, the object can be physically behind Earth’s curvature but is still visible because the light coming from it is refracted by the atmosphere.

There are many curvature calculators and simulation tools that don’t account for refraction. They would give us the correct results indicating the object’s physical positions but fail to show us the correct apparent position of the object when visually observed.

Flat-Earthers are often too happy with the calculator showing them the results they want to see and fail to see the reason for the discrepancy.

Predicting Eclipses Does Not Require the Saros Cycle or NASA’s Involvement

These days, predicting eclipses is easily done using computers. Prediction is made by determining the position of the Sun and the Moon at a time, and calculating if an eclipse happens. The same procedure is then repeated numerous time, each for a different time.

The victims of the flat-Earth dogma insist nobody can predict eclipses from the position of the Sun and the Moon. They believe NASA simply used the Saros cycle to predict eclipses by calculating the interval between eclipses. They are wrong.

The Lack of Stars in the Pictures of Space

In many pictures taken from space, stars are not visible, even with a dark sky. The reason is that stars are very dim compared to the primary object in the pictures. If the camera is set to take a correctly exposed image of an object that is much brighter than the stars, then the stars would not be visible in the picture. The same thing would happen everywhere, in space, or on the surface of the Earth.

Flat-Earthers often take the lack of stars as fakery. They are wrong. This is simply a limitation of any camera.