### Surface of Water and Communicating Vessels

Gravity is not the result of a particular shape of an object. It is caused by mass. All objects with mass exert gravity to each other. The larger the mass of an object, the greater the force of gravity.

On Earth, water forms a spherical surface which has the same center as the Earth. It applies to every surface of fluid which is under influence by Earth’s gravity, unaffected by another force. In a 10 cm wide container, the amount of curvature is only 0.0000002 mm. It is the reason the surface appears flat in small containers.

### Why Don’t We See Satellites in Photos Taken From The ISS?

“Why don’t we see satellites in photos taken from the ISS?” (or from space in general). That’s a recurring question within the flat-Earth community, usually asked without expecting an answer, assuming that an answer is impossible, and that it is a glaring oversight when the powers that be purposefully made the picture using CGI.

But no, the pictures are real. And satellites are not visible because they are too far spaced apart from each other.

### Misquotes of Nikola Tesla

Many flat-Earthers will tell you that Nikola Tesla is actually a flat-Earther. The supposed ‘evidence’ is a piece of quote that is claimed to be from Tesla himself; but in fact, it is not. It is actually a really terrible misquote, and an attempt to take the quote out of context.

The source of this problem is apparently a Facebook post that quotes Tesla, as well as a Facebook user named ‘Darrell Fox’.

### The Verrazano-Narrows Bridge and The Curvature of The Earth

Accounting for the curvature of the Earth is not usually needed for narrow high-rise building projects. Designers only need to ensure the foundation is flat, and the curvature of the Earth becomes non-factor.

For projects that extend over a long distance, like roads, railroads, canals, etc., they are built along the curvature of the Earth, and specifically accounting for the curvature is usually not needed.

But when the project extends on a long distance, as well as extending upwards, then we have no choice but to take the curvature of the Earth into account. One of such projects is the Verrazano-Narrows Bridge, New York, United States.

### ‘The Principle’: A Documentary Without Principle

‘The Principle’ is a pseudoscientific documentary that promotes geocentrism, that the Earth is stationary and the center of the universe. Despite the fact that the film has almost nothing to do with flat-Earth, some flat-Earthers decide to use this film to bolster their beliefs. Because after all, in the flat-Earth model, the Earth is stationary and the center of the universe, right?

This actually gets more complicated than that. We are dealing with two forms of pseudoscience, that sometimes even goes against each other.

### The Little Piggy Balloon Footage Proves Earth is a Sphere, not Flat

Little Piggy is the nickname of a helium balloon launched by IndianaCaver. It reached the altitude of almost 37 km before it finally ruptured and fell to the Earth. Before that, it took several hours of video, and IndianaCaver made these video available on YouTube.

Then, some flat-Earthers cherry-picked bits of the video where the horizon looked flat and presented it as ‘proof’ of flat-Earth. These are widely circulated in various memes and forms, even years after the originals were published.

But, can we use these videos as ‘proof’ of flat-Earth?

### Nikon Coolpix P900 and The Supposedly ‘Real’ Pictures of Venus

The Nikon Coolpix P900 camera is a very popular camera among flat-Earthers because there’s no other compact camera ever made that has such enormous zoom range. It is a unique and a very useful tool in this state of affair.

Someday, some flat-Earthers decided to bring their trusty P900s out and used them to take some pictures of Venus. To their delight, the resulting pictures don’t look like Venus we all used to know. They were too excited that they thought they have discovered an original ‘proof’ of global deception. “This is an irrefutable ‘proof’ that they have been lying to us!” so they say.

But, maybe there’s a simpler, more plausible explanation…

### Global Conspiracy Smoke and Mirrors

Some flat-Earthers use the so-called global conspiracy as an ‘escape hatch’ in order to abandon a losing argument without having to appear to lose face.

When being cornered, some flat-Earthers will tell you the ‘flat-Earth theory’ is a work in progress, it is normal for it to be incomplete, for now. “But, ” it is inevitable they would say this, “the most important thing is to uncover the global conspiracy and save the world from these unscrupulous few!”

In reality, the global conspiracy theory itself is simply their own invention.

### Curved Rocket Trajectory

Rockets follow a curved trajectory when going into space because their objective is not only to reach space, but also to enter Earth orbit. In Earth orbit, rockets have enough speed to counter Earth’s gravity and do not require a lot of energy to stay up there. To enter Earth orbit, a rocket needs to attain a high enough horizontal speed.

Flat-Earthers claim the curved trajectory of any rocket launch tells us no rocket has ever reached space. They are wrong. The curved trajectory is a way for rockets to enter Earth orbit.

### Midnight Sun in Both Polar Regions Proves Spherical Earth

Midnight Sun is a phenomenon where the Sun remains visible at midnight. This phenomenon occurs in the summer months north of Arctic Circle, and south of the Antarctic Circle.

The apparent motion of the Sun in both polar regions is different. In the north polar region, the Sun moves from left to right. On the other hand, in Antarctica, the Sun moves from right to left. There is no explanation other than that Earth is a sphere.

### The False Analogy of a Spinning Tennis Ball

The mass of the Earth exerts the gravitational acceleration of about 9.79 m/s² to everything on Earth’s surface toward the center of the Earth. On the other hand, the rotational motion of the Earth generates the centrifugal acceleration of about 0.03 m/s² away from the Earth. The net acceleration is about 9.79 m/s² toward the center of the Earth. That is why everything on Earth’s surface stays on the surface, not flying away to space.

Flat-Earthers often make a false comparison using a wet spinning ball. Water on the surface of a wet spinning ball does not stick to the ball; but the Earth is also round, wet and spins, yet everything stays on the surface. Then they make the erroneous conclusion that the Earth cannot be a spinning ball.

### The Direction of Sunrise and Sunset

We know for granted that during an equinox, the Sun rises from the east and sets in the west. Such facts are undisputed and have been verified through centuries of observation.

The flat-Earth model, however, is unable to accommodate this simple fact. And thus, it is not hard to conclude that the flat-Earth model does not represent reality.

### Space Flight and the Temperature in the Thermosphere

The thermosphere is a layer of the Earth’s atmosphere from about 95 km­ to 600 km. It is named ‘thermosphere’ because its temperature increases with altitude. The temperature in the thermosphere can reach 2500°C. However, air density in the thermosphere is very low to the point that heat conduction practically does not occur. Objects in the thermosphere will feel cold.

Flat-Earthers discovered that the temperature in the thermosphere could reach 2500°C. They are happy to ignore the other information which usually accompanies it: the air density up there is also far lower.

### Sunset at Burj Khalifa

Having the total height of about 830m, Burj Khalifa is the tallest building in the world. It is so tall that we can observe the sunset at the base of the building, then rush to the upper floors and watch the same sunset again for the second time on the same day.

This phenomenon can only happen if the Earth is a sphere. On a higher position, we will observe the sunset later than when we are closer to the ground.

### Consistency of Photos of the Earth

Every time NASA (or anyone else) releases a picture of the Earth from space; flat-earthers would compare it to another image of the Earth. Every photo is going to be different from another, but flat-earthers love to use this fact as a ‘proof’ that these photos are results of image manipulation, and that we are being deceived somehow.

### The Philosophy of CGI

When a photo of spherical Earth is pointed out to flat-earthers, they will dismiss it as CGI in the blink of an eye; even if they haven’t done any analysis at all. They do this because their belief in flat-Earth is not evidence-based, and any evidence contrary to their beliefs needs to be invalidated no matter how.

They are so used to doing it, and sometimes they become confused by it themselves, to the point that they would take the slightest hint of digital manipulation of any picture of the Earth as evidence of the flat Earth.

### Google Maps, GPS and Cellular Signal Reception

Google Maps and similar apps use satellite navigation —like the GPS— to determine the location of the device. The apps also utilize cellular data or other data connection to obtain map and route data, which are not part of the GPS or satellite navigation system.

Some flat-Earthers noticed that Google Maps does not fully function when the cellular signal is not available. They concluded that GPS signals are transmitted by cell towers, not satellites. In reality, Google Maps is not GPS. The app uses GPS —and other satnav systems— to determine user location. The maps and route data in the apps are not part of the GPS.

### Isaac Newton and The Law of Universal Gravitation

Isaac Newton formulated the law of universal gravitation which explained the motion of all celestial bodies in space known at his time. Also, he demonstrated that it is the same law that is causing everyday objects to fall to Earth.

Newton wrote that he had not been able to discover the reason for the phenomenon of gravity. Flat-Earthers use this as “proof” that he lied and he did not know anything about gravity, and that gravity was a mere fabrication. They are wrong. Gravity adequately explained the motion of all celestial bodies and the fact that everyday objects are falling to Earth. Newton simply did not know what is causing it.

### Psychological Projection

Why do we believe in conspiracy theories? According to research, one reason is the so-called ‘psychological projection’.

‘Psychological projection’ is a phenomenon where someone denies their attitude or traits and assumes instead that others are doing so. They see their negative qualities in others, even when the negative characteristics are not present in the others being accused.

### Polaris – The North Star

To most flat-earthers, the Earth is stationary. Stars are light sources attached to the firmament (for some mysterious reason), and they rotate around Polaris (again, for some mysterious reason).

However, they are missing the fact that Polaris is never visible from the southern hemisphere. And furthermore, the southern stars also rotate around the south celestial pole.