Blue Marble and the Visible Area of Earth’s Surface

The Blue Marble is an image of Earth taken by the crew of the Apollo 17 spacecraft on its way to the Moon. It was taken from a distance of 29000 km from Earth’s surface.

Flat-Earthers dismiss it by incorrectly asserting that the image covers a too-small area of Earth’s surface, due to their failure to account for the maps’ distortion.

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The Polar Azimuthal Equidistant Map is NOT the Flat Earth Map

The azimuthal equidistant map is a valid map. The map is a projection of the spherical Earth. Like every other map, it has distortions. It is not the “flat-Earth map,” and the usage of the azimuthal equidistant map does not endorse a flat Earth.

Flat-Earthers claim the shape of the polar azimuthal equidistant map as their own “flat-Earth map.” It is identical with the azimuthal equidistant map only in shape, but not in everything else. Unlike the azimuthal equidistant map, the so-called “flat-Earth map” does not represent reality.

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Distortion of Greenland on Maps

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Greenland is 1/14th the size of Africa. However, in a map with the Mercator projection, it appears the same size due to the distortion characteristics of the Mercator projection.

Flat-Earthers claim the distortion of the Mercator map is a failure of science to describe the world. In reality, distortion is a consequence of flattening a 3D shape into flat 2D media. Distortion also occurs with the azimuthal equidistant map, which is claimed by flat-Earthers as the so-called “flat-Earth map.” All maps have distortions: it is incorrect to assume the azimuthal equidistant map is distortion-free.

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Direction of the Qibla Proves Earth is a Sphere

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Muslims perform their prayers by facing the Qibla —or the direction to the Kaaba in Mecca, Saudi Arabia. The direction of the Qibla is traditionally determined from the direction to the Sun when the Sun is directly overhead the Kaaba. If the Sun is visible during that time, it will indicate the direction of the Qibla.

If the results of the observation are drawn on the so-called ‘flat-Earth map,’ the Qibla will not consistently point to the Kaaba. Only the calculation using the spherical Earth model will give us consistent results that conform to centuries of observation, from various locations on Earth. The reason is that the Earth is a sphere.

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Distortions of the Azimuthal Equidistant Map

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The azimuthal equidistant projection is a projection of the spherical Earth. As a result, a map using this projection has distortions in distances, shapes, directions, and areas. Just like the azimuthal equidistant map, all other types of maps have their distortion characteristics.

In the illustration, the eight yellow dots indicate a location 5000 km from the red dot, toward all the cardinal directions and the intermediate directions. We can see that the distances, shapes, directions, and areas are distorted in some way depending on the location on the map.

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Google Maps Live Traffic and Simon Weckert’s Virtual Traffic Jam

Google Maps live traffic works by crowdsourcing. It determines the current traffic by aggregating information sent by many phones carried by many different traveling users.

In February 2020, artist Simon Weckert successfully gamed the system and faked a traffic jam in Google Maps. He did that by pulling a cart full of active phones and walking in the middle of roads. Google Maps system thought there were many slow-moving cars on the road and regarded that as a traffic jam. As a result, during Simon’s operation, an empty road appeared as dark red in Google Maps, as if a traffic jam was ongoing.

Flat-Earthers claimed that it proves that satellites do not exist; possibly because they did not know how the system works. It might be that they previously thought the traffic data was obtained directly from satellite imagery. In reality, satellite navigation systems, like the GPS, is very much involved in the system.

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Air Map of the World 1943/1945

Flat-Earthers discovered a map titled “Air Map of the World” from 1943, explaining the flight routes during the time. Because the shape is identical to the fictional “flat Earth map,” they incorrectly claimed that it is a flat-Earth map. In reality, it is an azimuthal equidistant map that has distortions, a flattened shape of the spherical Earth on a flat surface, and does not depict the true shape of the Earth.

The exact nature of the map is even explained in a very detailed manner in the map’s description. Unfortunately, in the flat-Earth community, the map is passed around in a very low resolution, and therefore, the explanations become unreadable.

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Map Projections and Distortions

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The Earth is a sphere, a three-dimensional shape. But in most cases, we work with two-dimensional media, including paper, computer displays, televisions, phone screens, whiteboards, etc. To represent the Earth on a two-dimensional medium, it is necessary to transform the curved shape of Earth’s surface into a planar form using one of the many map projections.

All map projections necessarily introduce distortion into the results. Some flat-Earthers think that distortions are ‘evidence’ of failure of modern science to explain the world. In reality, the distortions are simply a consequence of transforming the curved surface into a planar form. It is impossible to create a map without distorting it in some fashion, the same way it is impossible to perfectly flatten a ball without cutting it.

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Perth–Johannesburg Flight Route

Some flat-Earthers noticed some flights from Perth to Johannesburg have a flight change in Dubai. They use the fact to ‘prove’ a flat Earth. In reality, there are non-stop flights of the same route that are impossible to explain if the Earth is flat.

With a flight change in Dubai, the flight takes more than twice as long, as Dubai is nowhere near the non-stop flight path. In fact, Perth–Dubai is a longer hop than the direct Johannesburg–Perth route. These are consistent only with a spherical Earth and can never be explained if the Earth is flat.

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How GPS and Other Satellite Navigation System Work

A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. Several satellites continuously transmit signals containing their positions and the time when the signal was sent. Receiver units listen to the signals and use the information to calculate their positions.

Flat-Earthers assume that if GPS satellites are used to determine positions, then they should be able to pinpoint the position of a receiver. They are wrong. GPS satellites only transmit signals but never receive signals from the receivers. It is impossible for the satellites to determine the position of a receiver.

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The Taiwan–Los Angeles Flight (not from Bali) that was Diverted to Anchorage

There was a flight from Taiwan to Los Angeles that was diverted to Anchorage because one of the passengers gave birth to a baby. Flat-Earthers use the case as one of the first “evidence” from flight routes proving Earth is flat.

They are wrong. The case only tells us about the ignorance of these flat-Earthers about the distortion in a map projection. Their argument started with an elementary mistake of taking a straight line on a Mercator map between Taiwan and Los Angeles, and assume it as the “intended flight path.”

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Astrolabe is an astronomical instrument for measuring the altitude of the sun or stars, and to determine the solution of various problems in astronomy, time, and navigation. Astrolabe was used from classical antiquity, about 2nd century BC,  until the age of discovery where it was superseded by the more accurate sextant, star charts, and time-keeping devices.

Flat-Earthers claim that astrolabes can only work because the Earth is flat. They are wrong. Astrolabes were designed using the spherical Earth model. To use an astrolabe, a good understanding of the spherical Earth model is required.

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The Failure of Flat-Earth Model to Explain Emergency Landings That Occur More to the South

The perpetrators of flat-Earth often take emergency landings as ‘proof’ of a flat Earth. They would point out that the diversion airports used for such emergency landings are somehow consistent with the flat-Earth map.

It is not a coincidence that all the cases of emergency landing they pointed out occurred far in the north. At the locations closer to the north pole, the distortion of the azimuthal-equidistant map (claimed by flat-Earthers as the ‘flat-Earth map’) diminishes. It would seemingly appear as if the ‘flat-Earth map’ can explain the choice of the diversion airports. In many other locations, though, the flat-Earth map would fail to explain it.

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The Gleason Map

The “Gleason Map” is a map with the azimuthal equidistant projection, centered on the north pole. The Gleason Map is not a scaled-down figure of the Earth, but it is merely a projection of the actual, spherical shape of the Earth, like every other map.

Alexander Gleason —the creator of the map— claimed that the map depicts the shape of the ‘flat Earth’. The majority of the flat-Earth communities adopt this map as ‘the flat-Earth map.’ They are wrong. The map is merely a projection of the spherical shape of the Earth, just like every other map types.

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Day and Night Areas on a Flat Earth

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At any given time, there is an equal area of the Earth that is experiencing daytime, and that is having a night time. The reason is that the sun is very far, and it would illuminate a hemisphere of the Earth, and leave the other dark.

If we plot which areas of the Earth that are getting sunlight on an azimuthal equidistant map centered on the north pole, the sun would appear to illuminate a somewhat elliptical area during the northern hemisphere summer, and a lopsided Bat-Signal shaped area during the winter. During the equinox, the sun would appear to illuminate a half-circle area.

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James Cook’s Second Voyage

James Cook made three significant voyages to the Pacific Ocean. Flat-Earthers often made their case with his second voyage. In this voyage, James Cook was tasked to find the hypothetical continent, the Terra Australis, that was predicted to be around the southern Pacific Ocean. In his second voyage, James Cook proved no such continent exists.

Flat-Earthers often take the second voyage of James Cook as ‘proof’ that Antarctica is not a continent, but a massive landmass encircling the flat-Earth. Their ‘proof’ is that Cook traveled more than 60000 miles, and 60000 miles is much farther than the circumference of Antarctica. They are wrong.

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Polar Circumnavigation

Flat-Earthers think there hasn’t been anyone who has circumnavigated the Earth by traversing both the north pole and south pole in the process. All we have are explorers who have circumnavigated the Earth to the east or west, parallel to the equator; explorers like James Cook or Ferdinand Magellan. They don’t really have the choice, because if polar circumnavigation is possible, then the flat-Earth assumption falls flat.

But, like a lot of assumption in the flat-Earth community, it is simply not true. There are in fact many people who have done a polar circumnavigation, and the information can be easily found on the Internet.

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Non-Stop Long-Haul Flight Routes in the Southern Hemisphere

There are many non-stop long-haul flight routes between two locations in the southern hemisphere, all without crossing the northern hemisphere. These routes can only exist if Earth is a sphere.

Some flat-Earthers claim there is no non-stop long-haul flights between two locations in the southern hemisphere. Flights need to make a stop in a location in the northern hemisphere because the distance will be too far and such flight will traverse the northern hemisphere, or more accurately, the center of the Earth according to their model. They are wrong. There are many such flight routes.

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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.

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