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.
Continue reading “How GPS and Other Satellite Navigation System Work”
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 during the time the Sun is visible, 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.
Continue reading “The Direction of the Qibla Proves Earth is a Sphere”
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.”
Continue reading “The Taiwan–Los Angeles Flight (not from Bali) that was Diverted to Anchorage”
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 Astrolabe was used from classical antiquity, about 2nd century BC, until the age of discovery where it was superseded by the more accurate sextant, star charts, and time-keeping devices.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 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.
Continue reading “The Failure of Flat-Earth Model to Explain Emergency Landings That Occur More to the South”
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.
Continue reading “The Gleason Map”
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.
Continue reading “Day and Night Areas on a Flat Earth”
The Earth is a sphere, a three-dimensional shape. But most of the time, 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 the 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. They are wrong.
Continue reading “Map Projection and Distortion”
Flat-Earthers claim the logo of the United Nations is the so-called ‘flat-Earth map’. They are obviously wrong, the logo is a map of the Earth in the azimuthal equidistant projection. They picked the design because it shows all the countries of the Earth, and without emphasizing one over another.
Continue reading “United Nations Logo Conspiracy Theory”
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.
Continue reading “James Cook’s Second Voyage”
Flat-Earthers often point out to a ‘map’ that they think represents ‘the real Earth’. At a glance, it looks identical to the azimuthal equidistant map centered on the north pole. But both maps are in fact fundamentally different. The polar azimuthal equidistant map is not the so-called flat-Earth map.
Continue reading “The Polar Azimuthal Equidistant Map is NOT the Flat Earth Map”
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.
Continue reading “Polar Circumnavigation”
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.
Continue reading “Non-Stop Long-Haul Flight Routes in the Southern Hemisphere”
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.
Continue reading “Google Maps, GPS and Cellular Signal Reception”
We cannot take a straight line between two locations on a map and consider that line the shortest distance between the two locations. With a very short distance —like within a city— it wouldn’t usually matter. But for long-haul flights across continents, then it would matter a lot.
Flat-Earthers are known to use this mistake —whether deliberately or not— as a ‘proof’ that the Earth is flat. A common case they would bring is emergency landings.
Continue reading “Emergency Landings and Flight Route”