In images taken using a fisheye lens, a straight line will remain straight if it crosses the center of the image. We can use this attribute to determine if a line is straight in reality.
In any fisheye videos taken from a high altitude, there should be plenty of moments where the horizon crosses the center of the image, and we can use those to determine that the horizon line is curved in the real world.
Continue reading “Fisheye Videos”
We cannot feel the Earth rotating, and to explain the phenomenon, we usually use the moving vehicle analogy. If the vehicle is moving at a constant speed, we will not be able to sense the motion. We cannot feel the motion of Earth because of the same reason.
Flat-Earthers invented the excuse that we are standing on Earth, not inside it, to falsely reject the explanation.
Continue reading “Moving Vehicle Analogy and the Physical Barrier Excuse”
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.
Continue reading “Map Projections and Distortions”
The Southern Cross or Crux can be observed from the south of 26°N, and it is always visible south of 26°S. On a flat Earth, it should be visible from the outer parts on Earth at the same time, but not from the central areas, disproving the flat model. The visibility of Crux is only consistent with the spherical Earth model.
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A vacuum implosion can occur if a sealed enclosure has less pressure inside it than outside it, and the structure is not designed to withstand the pressure difference.
Flat-Earthers use vacuum implosions to ‘disprove’ space travel in the vacuum of space. In reality, 1. it is possible to engineer structures that can withstand such a pressure difference; and 2. in space, the inside is pressurized while the outside is a vacuum, which simplifies the engineering considerably.
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The quality of a photograph depends on the quality of the equipment. Higher quality equipment tends to give us better results than lower quality ones.
Flat Earthers like to use their Nikon P900/P1000 to take a picture of planets. When they discover their results have far worse quality than the images from NASA, they would conclude NASA must have faked them. In reality, it was due to their equipment are not in the same league as NASA’s, not to mention the skills to operate the equipment.
Continue reading “Quality of a Photograph”
Tides are the result of the variation of lunar gravitational acceleration over all the material of which the Earth is composed. They are not caused by the magnitude of such acceleration exerted on a specific location only.
Flat-Earthers discovered that the position away from the Moon is also having a tide, not just the location where the Moon is directly overhead. Then, they were happy to proclaim that it is a failure of science to explain tides. In reality, tides are the result of the variation of lunar gravity over the entire Earth, not just the magnitude of the lunar acceleration on a single location only.
Continue reading “Antipodal Tide”
If we look south in any location in the southern hemisphere, we will see the same set of stars. The stars are seen rotating around the south celestial pole, in the Octans constellation, near the star Sigma Octantis.
This phenomenon can never be explained in the flat-Earth model. Looking at the so-called ‘flat-Earth map’, we should see another set of stars on a different location in the southern hemisphere. The reason is that the flat-Earth model is a false representation of the Earth.
Continue reading “Stars in the Southern Sky: Evidence That the Earth is a Rotating Sphere”
An egg will generally sink in freshwater, but if we pour salt into the water and stir it, then the egg will start to float. The reason is that after salt is added, the density of water increases. However, the relationship between density and if the egg floats or sinks is not a direct causality.
Flat-Earthers claim that the phenomenon “proves” things fall because of density, and that gravity does not exist. In reality, the density of the water determines the magnitude of buoyancy the egg receives. If the buoyancy is higher than the weight of the egg, the egg will float, and vice versa.
Continue reading “Egg and Salt Water”
The United Arab Emirates astronaut, Hazza Al Mansouri, took pictures of Earth’s features like the Nile and the Persian Gulf during his visit to the ISS. Flat-Earthers claim the pictures are fake because the various objects appear very large compared to the size of the Earth in the picture. The reason is that they do not understand that the ISS is only about 400 km above Earth’s surface, and only a very small amount of the Earth’s surface is visible from the ISS
Continue reading “Pictures of Earth’s Surface from the UAE Astronaut Hazza Al-Mansouri”
Due to Earth’s axial precession, the positions of Earth’s celestial poles shift gradually in a cycle of approximately 26000 years. These days, Polaris is very close to the north celestial pole. However, 19 centuries ago, Kochab is much closer to the celestial pole than Polaris.
Flat-Earthers claim that the stars are always in the same position proves the Earth is stationary. An ancient star chart like Almagest from the 2nd century shows them wrong. The stars today were not in the same place as stars 19 centuries ago.
Continue reading “Ptolemy’s Almagest and Earth’s Axial Precession”
The International Space Station (ISS) is only about 400 km above the Earth’s surface, only 6% farther from the center of the Earth than the Earth’s surface. Therefore, only a very small part of Earth’s surface is visible from the ISS at any time.
Flat-Earthers like to examine photos of the Earth from the ISS and compare them to those taken from a much farther location. They would take any difference as an inconsistency. In reality, the ISS can only observe a very small part of the Earth, unlike spacecraft much farther away.
Continue reading “View of the Earth from the ISS”
The various images of the Lake Pontchartrain power lines taken by Soundly and others easily demonstrate the curvature of the Earth. In a desperate attempt to “debunk” the images, a group of flat-Earthers made an “analysis”, but failed to locate the correct power lines. They incorrectly “analyzed” another power lines on the same lake, just not the ones being presented as a demonstration of Earth’s curvature.
The erroneous “analysis” spread in flat-Earth communities as a hoax, as though it “debunks” the actual power lines in the demonstration.
Continue reading “Misleading “Debunking” of the Lake Pontchartrain Power Lines Images”
Jumping to conclusions (also called the JTC bias or inference-observation confusion) is a psychological term referring to the failure to distinguish between observation and inference. In other words, “when I fail to distinguish between what I observed first hand from what I have only inferred or assumed.”
Many flat Earth “facts” are simply the results of jumping to conclusions. They judged something without having all the facts, to reach unwarranted conclusions.
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Shanghai, China and Buenos Aires, Argentina are a near antipodal pair. Both are located at the diametrically opposite points to each other on Earth’s surface. Therefore, we can fly from Buenos Aires in any direction and arrive in Shanghai after traveling a roughly similar distance, regardless of the course taken.
Any flight between an antipodal pair has a similar duration even though the different flights have different directions. This fact is only consistent with spherical Earth and cannot possibly be explained if Earth is flat.
Continue reading “Antipodal Flight: Shanghai–Buenos Aires”
In a Big Think Q&A, Bill Nye gave his opinion on why we cannot throw our trash into space. Flat-Earthers took Bill’s words out of context and used it to “disprove” space flight.
“Why we don’t throw trash into space? Because it’s too expensive. Lifting a ton of material into space takes an extraordinary amount of rocket fuel. And, by the way, when people want to send this much plutonium-238 which is not even the weapon’s plutonium, a baseball size, a grapefruit size, people freak out because the rockets sometimes blow up.”
“Now, one thing I really want your generation to embrace is that the Earth is a closed system. We cannot leave the Earth. There’s no place to go. There’s no place to throw your trash. And I wouldn’t be surprised if maybe not you but your kids develop ways to mine our landfills.”
Unscrupulous flat-Earthers took the specific part “Earth is a closed system. We cannot leave the Earth. There’s no place to go,” and presented it as if Bill was telling us we cannot go to space. From the complete video, it is clear that it is not what Bill meant.
Bill Nye is a space colonization skeptic. He does not believe space colonization is realistic. It does not mean Bill thinks we cannot go to space. In another Q&A, he said we need to have a presence on Mars for research purposes.
Continue reading “Bill Nye and the “Closed System” Quote”
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.
Continue reading “Perth–Johannesburg Flight Route”
The Big Dipper is a bright asterism in the northern celestial sphere. It is always visible north of 41°N and hidden south of 41°S. Flat-Earthers noticed that the Big Dipper is visible all year and use the fact to ‘prove’ a flat Earth. In reality, the visibility of Big Dipper depends on the latitude of the observer.
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In making mathematical models, physicists often remove real-world details that have little influence over the final results for simplifications. In flight-dynamics, it is often perfectly adequate to assume Earth is flat & non-rotating, even if the aircraft is flying over spherical & rotating Earth.
Some flat-Earthers claimed to have exposed ‘a secret document’ from NASA saying that Earth is flat & non-rotating. They are wrong. The document is simply a derivation of a flight dynamics problem, assuming flat and non-rotating Earth, which is a common assumption made to simplify flight models. It does not imply the Earth is flat and non-rotating.
Continue reading “Flight Dynamics: Simplification by Assuming Flat & Non-Rotating Earth”
The Sun is 1,391,016 km (864337 mi) in diameter and 146,600,000 km (93,000,000 mi) from us. These facts are consistent with everyday observations.
Flat-Earthers have a different idea about the distance and the size of the Sun. However, on careful examinations, the numbers are inconsistent with everyday observations.
Continue reading “Proportions”