Wind & Jet Stream Excuses

Flight durations are a useful proxy for the distances between cities and easily debunk flat Earth. Flat-Earthers invented the “explanations” that the discrepancies of the flight durations in the flat Earth model are caused by winds and jet streams.

In reality, the required wind speed in such a scenario far exceeds the typical jet stream speed. Furthermore, the wind does not affect similar routes the same way in the flat Earth model. And we can easily account for the wind speed differences by averaging the flight durations in both directions. Continue reading “Wind & Jet Stream Excuses”

Singapore–New York and Melbourne–Santiago Flight Routes

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As of 2020, the Singapore–New York flight route is the world’s longest flight route, while the Melbourne–Santiago route is the most southernmost route. The real-world durations of these routes are only consistent if Earth is a sphere.

On the flat-Earth model, the Melbourne–Santiago flight route should be a longer flight than the Singapore–New York route. These routes’ real-world durations disprove the flat-Earth model.

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Airplanes Do Correct for the Coriolis Effect

Airplanes do correct for the Coriolis effect. They constantly make adjustments to counter forces that try to push them away from the planned route, including the Coriolis force.

Flat-Earthers claim the Coriolis effect does not appear to affect airplanes, and they use it to “prove” that Earth is stationary. In reality, the Coriolis effect does affect airplanes, and we do have to correct for it. But the effect is tiny, and we can safely ignore it in flight planning.

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Sydney-Johannesburg Flight Route

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The existence of the non-stop Sydney-Johannesburg flight route is only possible if Earth is a sphere. We can find that out by comparing its duration to the same route but with a stop.

There are other Sydney-Johannesburg flight routes, but with a stop, like in Dubai. Flat-Earthers use the existence of these routes to “prove” a flat Earth. In reality, it does not mean the non-stop route does not exist & it is not difficult to verify that the non-stop route exists.

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Polar Circumnavigation

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Polar circumnavigation is complete navigation around Earth through both the North Pole and the South Pole. Several parties have successfully done it, and it is only possible if Earth is a sphere.

Flat-Earthers incorrectly claim that Earth circumnavigation has never been done through both the poles, and they use it to “prove” a flat Earth. In reality, many have successfully done such feats.

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Flight Routes During the COVID-19 Pandemic

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During the COVID-19 pandemic, many flight routes are being canceled, suspended, or cut down due to lockdowns, travel warnings, travel bans, or insufficient demand. These include flight routes that are impossible if Earth were flat.

Flat-Earthers looked for these routes, and when they could not find them, they use the lack of these routes to “prove” Earth is flat. In reality, they made these lookups during the COVID-19 pandemic, when most of these routes are not available or severely cut down.

Airplanes and Earth’s Rotation

An airplane exists on Earth. It has the same motion as the surface of the Earth, including Earth’s rotating motion. The motion and speed of an airplane are measured relative to Earth’s surface.

Flat-Earthers claim that an airplane should not be able to fly eastward or land. In reality, an airplane is moving relative to the surface. It has Earth’s motion as a component of its motion and does not need to chase Earth’s rotation.

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Pilots Are Taught to Work With the Fact Earth is a Sphere

Pilots are taught to work with the fact that Earth is a sphere. It is part of the education to become a pilot. Their job depends on the knowledge that Earth is a sphere.

Flat-Earthers wrongly claim that pilots are taught to fly based on a flat Earth. We can easily disprove these claims by reading some of the books these pilots use in their education.

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Flight Dynamics: the Assumption of Flat & Non-Rotating Earth for Simplification

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 final aircraft will be flying over spherical & rotating Earth.

Flat-Earthers claimed to have exposed ‘a secret document’ from NASA, saying that Earth is flat & non-rotating. In reality, 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.

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Eötvös Effect: Direct Evidence Earth is a Rotating Sphere

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Eötvös effect is the change in perceived gravitational acceleration when moving eastward vs. westward. An object will weigh slightly more when moving westward than when it is stationary or moving eastward.

The slight difference in weight due to the Eötvös effect can be measured in an experiment on a flight. The Eötvös effect is direct evidence that the Earth is a rotating sphere.

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Airspeed of Long-Haul Commercial Passenger Flights

The durations of commercial passenger flights are useful proxy data for the distance between cities. They easily debunk flat-Earth. Flat-Earthers invented “explanations” that different airplanes have different airspeeds to dismiss the data. In reality, all current long-haul airliners have a similar cruising speed.

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Airplanes Will Never Fly Into Space

An airplane relies on the lift from its wings, which depends on the airplane’s speed and the air density. As a result, a cruising airplane will fly at a constant altitude, following the curvature of the Earth.

Flat-Earthers claim if Earth is a sphere, an airplane has to dip its nose down periodically, or it would fly into space. In reality, an aircraft will follow Earth’s curvature and is unable to fly to space even if the pilot deliberately attempts to do that

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Spirit Level on an Airplane

During cruising, an airplane is practically level. It is flying perpendicular to the direction of gravity. The aircraft is still flying following Earth’s curvature and continuously changes its orientation. However, not only its orientation changing but also the direction of gravity, having the same amount of change. As a result, a spirit level on a flight will not show us the difference in orientation of the airplane due to its motion following the curvature of the Earth.

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Antipodal Flight: Auckland–Madrid

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Auckland, New Zealand and Madrid, Spain 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 Auckland in any direction and arrive in Madrid after traveling a roughly similar distance, regardless of the direction 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.

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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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Antipodal Flight: Shanghai–Buenos Aires

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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.

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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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New York JFK – Moscow SVO Flight Time-Lapse Videos

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There are several time-lapse videos taken on board of a New York – Moscow flight, looking northward through a window on the left side. In the videos, the sky never looked fully dark, and the sun was visible most of the time on the flight.

Flat-Earthers erroneously assumed that the phenomenon is not possible if Earth is a sphere and that it is “evidence” the Earth is flat. In reality, everything in the videos can be easily explained and is fully consistent with the spherical Earth model.

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Human Perception of Speed and Acceleration

When aboard an airplane flying at cruising speed, we will not be able to feel that the plane is, in fact, moving at speed of more than 900 km/h. But if the plane changes its speed, turns or changes its altitude, we can easily feel it.

The same thing happens with the motion of the Earth. Due to Earth’s rotation, the surface of the Earth is moving at 1656 km/h near the equator. We never feel it because the speed is constant, or in other words, the acceleration is zero.

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Air Distance vs Surface Distance

The cruising altitude of a jet airliner is about 33000-42000 ft or 10000-12800 m. It is very tiny compared to the radius of the Earth of 6378 km. Therefore, the distance measured at the cruising altitude does not differ much compared to the surface distance.

Some flat-Earthers claim that if Earth is a sphere, the distance traveled by a jet airliner would have been multiple times the surface distance. They are wrong. The air distance at 33000 ft is only 0.16% farther compared to the surface distance.