Detecting Earth’s Rotation by Draining Water

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The Coriolis effect does not determine which direction water swirls down sinks or toilets because the effect is tiny & masked by other, much stronger factors. However, by eliminating these other factors, water will consistently swirl counterclockwise well North of the Equator and clockwise well South. This phenomenon proves Earth is a rotating sphere.

Flat-Earthers noticed the myth about water swirling down sinks & use it to dismiss the Coriolis effect. In reality, it is only a myth because other factors mask the Coriolis effect. Removing these factors lets us observe the water swirling from the Coriolis effect alone.

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Nobel Disease

Nobel disease is a phenomenon where a Nobel Prize winner endorses a pseudoscientific concept in their later years.

Conspiracy theorists use these endorsements as “evidence” science supports their crank ideas. In reality, science relies on the scientific method to discover what is true, rather than the authority of any individual, not even Nobel Prize winners.

We have no problem saying that psychic is pseudoscience even though some Nobel prize laureates at one point endorsed it. Just because renowned scientists like Pierre Curie, Marie Curie, and Albert Einstein supported psychic, it does not mean it is scientific.

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Ancient Greeks and Spherical Earth

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Ancient Greeks have known spherical Earth since at least the 3rd century B.C. According to historian Otto E. Neugebauer, the Greeks discovered Earth is a sphere from the drastic variation in the stars’ positions & motions between Greek settlements of different latitudes.

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Tide

Tides are caused by the difference in the strength and direction of lunar and solar gravity received by the different locations on Earth.

Much flat-Earth misinformation about tides arises from the wrong assumption that tides are caused by the strength of lunar gravity received by a specific location alone. In reality, tides are caused by the gradual change in the moon’s gravity over the entire Earth.

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Flat-Earth Laser Tests are Misleading

Flat-Earthers’ laser tests are misleading. They pointed the laser from near the surface toward a distant observer. If the observer sees the beam, they conclude Earth is flat. It was a misunderstanding about laser & how atmospheric refraction affects it.

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Front-Facing Cameras in Rocket Launches

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Cameras on rocket launches are there to evaluate performance and observe potential problems. They are also helpful for public relations. They rarely have a camera looking up because there is usually nothing important, useful, or interesting.

Flat-Earthers claim that there is no front camera in rocket launches because “they are hiding something.” In reality, a few launches have a front camera like the Space Shuttle STS-133 mission above & it is as unremarkable as anyone would expect.

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Sweden Solar System

The Sweden Solar System is the largest scale model of the Solar System in the world. We can use it to get a better sense of the sizes and distances in the Solar System.

Flat-Earthers claim there is no scale model of the Solar System and use the fact to “prove” the failure of science to explain the world. The Sweden Solar System proves them wrong and gives us an idea about the problem of making a scale model of the Solar System.

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Zooming In on the Horizon From Space

Flat-Earthers often make an unreasonable demand that astronauts in space zoom in using a camera toward the upside-down horizon to reveal an upside-down object on the horizon.

If we cannot zoom in toward the horizon from a flight to reveal objects on the horizon, then it is unrealistic to expect astronauts to be able to zoom in to reveal objects on the horizon.

Horizon’s distance from a flight is approximately 350 km. We cannot zoom in on an object that far away because it is beyond the visibility range and would require a huge camera lens to resolve it. And it will be much more unrealistic to do it from space.

Zero-G Aircraft and Duration of Weightlessness

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A zero-gravity aircraft flies in a parabolic motion following a free-fall motion to provide a brief weightless environment.

Flat-Earthers claim videos of astronauts in space were faked in zero-gravity aircraft. In reality, a zero-gravity plane can only provide ~25 seconds of continuous weightlessness and cannot be used to film long-take videos in a weightless condition.

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Scientific Theory is not “Only a Theory”

The word “theory” has multiple meanings and can be ambiguous. Its meaning in a scientific context can be different from that in the context of everyday communication. Flat-Earthers erroneously assume we call it a “scientific theory” because it is still unproven. In reality, in the scientific context, a theory is commonly regarded as correct, & we call an unproven supposition a “hypothesis.”

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Coriolis Tourist Trap

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It is a myth that the Coriolis force determines which direction water spirals down drains in everyday cases. The Coriolis force is too small in such cases. Sadly, charlatans have been using it as a tourist trap near the Equator, exploiting unsuspecting tourists.

Flat-Earthers realized the Coriolis tourist trap was just a parlor trick & used it to dismiss the Coriolis effect. In reality, scientists have been debunking this myth all the time. It is flat-Earthers who were duped into thinking it is a genuine scientific argument.

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Map Projections and Distortions

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Earth is a sphere. But we generally work with two-dimensional media (paper, computer displays, televisions, phone screens, whiteboards, etc.), and it is necessary to transform the curved Earth’s surface into a planar form using a map projection.

All maps have distortions, and flat-Earthers use it to discredit science. In reality, distortions are the result of transforming a curved surface into a planar form & cannot be avoided. Some distortions can be tolerated, and some are not. It is why there are many different map projections for different purposes.

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Moonlight and Inverse Square Law

Light intensity is inversely proportional to the square of its distance. The light we receive from the Moon increases 50000× if we land there. But so does the Moon’s apparent size, spreading the increase in intensity over a larger area.

Flat-Earthers incorrectly claim the inverse square law means the Moon would be too bright if we land there, and they use the argument to “prove” it is impossible to go to the Moon. In reality, the inverse square law applies to a point source. For a large light source, its change in apparent size must also be considered.

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Albert Michelson in “Michelson and the Speed of Light”

In 1881, Albert A. Michelson experimented to prove the existence of aether. Aether was a hypothesized material that fills the region of the universe. Scientists knew light is a form of a wave, and because all other waves require a medium to propagate, they formulated the aether hypothesis, in which light can propagate. However, Michelson’s attempt produced a null result. Michelson concluded that the hypothesis of a stationary aether is erroneous.

In 1960, Bernard Jaffe wrote Michelson’s biography in the book “Michelson & the Speed of Light.” Unscrupulous flat-Earthers quoted a lone paragraph from the book out of the intended context and presented it as if Michelson proved the Earth is stationary.

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NASA’s Non-Fisheye Images

NASA maintains a database of astronaut photography in eol.jsc.nasa.gov that we can search by many parameters, including focal length. By searching for focal length above 28mm, we can ensure the resulting images are not fisheye.

Flat-Earthers claim all NASA images are fisheye. In reality, most images in eol.jsc.nasa.gov are not fisheye. NASA also preserves the images’ EXIF data containing the camera & lens info. Sometimes even the raw images are available.

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Shooting Distance and the Magnitude of the Coriolis Effect

Because Earth is a rotating sphere, the Coriolis effect deflects the flight of a bullet to the right in the Northern Hemisphere & to the left in the South. The effect is tiny in most practical shootings and only needs to be considered in long-range shootings.

Many soldiers are not trained to account for the Coriolis effect, & flat-Earthers use it to “prove” it does not exist. In reality, most soldiers do not shoot long range. It is unnecessary to consider a few mm of deflection if the target is as large as an enemy soldier.

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Changing Camera Zoom Changes the Exposure in Automatic Mode

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A camera in automatic mode will evaluate the entire scene and choose the exposure automatically. If the entire scene appears too dark, the camera will increase the exposure. If the entire scene is too bright, it will decrease the exposure.

If the intended object is small, bright, and on a dark background like a sunset, changing zoom will affect the overall brightness of the entire scene. The automatic mode might choose an incorrect exposure. It is the source of much flat-Earth misinformation & can be corrected using manual exposure.

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Different Reasons Why a Distant Object is Not Visible

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Different reasons can cause a distant object to be not visible:

  1. The angular resolution limit of the observer.
  2. The visibility limit imposed by the atmosphere.
  3. Obstruction by another object, including by Earth’s curvature.

Flat-Earthers incorrectly presumed “a distant ship is not visible only because of Earth’s curvature.” Incorrectly concluded if we can bring the ship back into view, the curve must not exist. In reality, Earth’s curvature is not the only thing that can cause a distant ship to be not visible; other reasons can also cause it.

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Reasons for Preferring Flight Routes With a Stop to the Non-Stop Routes

Many flight routes cannot possibly exist if Earth is flat. Flat-Earthers showed the availability of the same routes with a stop to “prove” the non-stop routes do not actually exist. In reality, there are reasons airlines provide these routes with a stop, and some passengers do prefer to fly these routes.

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Demonstration Using a Glass of Water at the Tiangong Space Station

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Chinese astronauts performed science demonstrations at the Tiangong Space Station. One of these demonstrations involves a glass of water and a ping-pong ball. Flat-Earthers saw a photo of the glass of water from the set, and they used it to discredit spaceflight. They claim that if it is really in space, then the water and glass should float.

In reality, the glass was attached to the table, and the water stayed in the glass because of adhesion between the glass and water, not gravity. The surface of the water also bulges and is not level with the glass or the table, as expected in a microgravity environment.

The astronauts used the set to demonstrate buoyancy in space. They pushed a ping-pong ball into the water, and it did not float like on Earth. At the end of the demonstration, they detached the glass from the table and floated it with the water & the ping-pong ball still inside it, and everything behaved as it should in a microgravity environment.

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