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 Astrolabe was used from classical antiquity, about 2nd century BC, until the age of discovery where it was superseded by the more accurate sextant, star charts, and time-keeping devices.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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Magnetic dip is the angle between the horizontal and Earth’s magnetic field. A compass needle, for example, will not point north and south, but will also have a dip. It tends to dip at an angle toward the Earth (and to the sky). The dip is generally greater toward the pole. At various locations close to the equator (but not exactly at the equator), the dip is zero.
Magnetic dip as observed on various locations on Earth can only happen if the Earth is spherical.
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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”
A crow’s nest is a structure in the upper part of the ship, especially old-fashioned ones. It is used as a lookout point and positioned high above to increase visibility over the curvature of the Earth.
On the deck of a ship 4 m (13 ft) above the surface of the ocean, an observer can spot a 20 m (66 ft) high ship from at most ±25 km (16 mi). On the other hand, from a 35 m (115 ft) high crow’s nest, an observer will be able to spot the same ship from ±40 km (25 mi) away.
On modern ships, the role of a lookout is replaced by radars. And for the same reason, a radar is positioned in the upper part of a ship.
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Long before GPS, navigators used a device called ‘sextant’ to determine the angle of a celestial body. From that data, the latitude of their current location can be determined.
This can only happen if the Earth is spherical.
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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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The GPS system is one-way. The satellites broadcast signals. GPS devices receive and process the signals to determine their location.
Flat-Earthers often point out the fact we were unable to locate the ill-fated MH370 as ‘evidence’ GPS doesn’t work and therefore doesn’t exist. They are wrong. GPS satellites never receive any signal from GPS devices, and it is not possible for them to locate MH370.
Continue reading “The MH370 Disaster and the Inability of the GPS System to Locate It”
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.
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Flat-Earthers often claim that the fact Polaris not appearing to move is ‘evidence’ that the Earth is flat and stationary. If the Earth is a rotating sphere, then Polaris —as they say— should appear to be in motion.
In reality, Polaris is indeed moving across the sky. Though it is not something we can observe in a single night, or even in our entire lifetime.
Continue reading “Polaris: Our Current North Pole Star, But Not For Forever”
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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