A frame of reference consists of an abstract coordinate system and the set of physical reference points that uniquely fix the coordinate system and standardize measurements. Speed or velocity is relative to a frame of reference. It is possible that two speeds/velocities are measured relative to a different frame of reference and thus cannot be directly compared.
Flat-Earthers would often compare two different speed measurements like an airplane moving at 900 km/h (560 mph) and Earth’s surface near the equator at 1674 km/h (1040 mph). They would conclude the airplane should not be able to catch up with Earth’s surface and would not be able to land if the Earth is rotating. They are wrong. The speeds are measured relative to the different frame of reference, and therefore, cannot be compared directly.
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On Earth, daylight sky is glowing in bright blue due to Rayleigh scattering. Sunlight is scattered in every direction by the oxygen and nitrogen molecules in Earth’s atmosphere.
Such the phenomenon does not happen on the Moon, causing the dark sky of the Moon. Flat-Earthers claim that the dark sky of the Moon captured by photos and videos taken from the Moon are “proof” there is misconduct. They are wrong. Just because Earth’s sky is bright blue, it does not mean it will be like that on the Moon and other planets.
Continue reading “The Dark Sky on the Lunar Daytime”
We can determine if a star is visible from a specific location using the declination of the star and the latitude of the observer, subject to other conditions like observer’s topology, the magnitude of the star, weather conditions, etc. It is possible to do this because Earth is a rotating sphere.
If the Earth is flat, every star would have been visible all night from every location. We don’t see the same stars every night because some of them are below the horizon and obscured by the Earth.
Continue reading “Determining the Visibility of a Star From Its Declination and the Observer’s Latitude”
Earth’s atmosphere is part of the Earth. It practically follows Earth’s rotating motion like the rest of the Earth. Due to various factors, Earth’s atmosphere has relatively small and uneven movement relative to the surface. We call it ‘wind.’ The fastest wind ever recorded is about 408 km/h, relative to Earth’s surface.
Many misconceptions about Earth arise from the wrong idea that only Earth’s solid body is rotating, but the atmosphere is not. If it is true, then we should always feel the wind with the speed of 1674 km/h near the equator, or more than 4× the fastest wind ever recorded. We don’t feel such a wind, and thus we know our atmosphere is moving at practically at the same speed as Earth’s surface.
Continue reading “Earth’s Atmosphere Rotation”
Gravity is a natural phenomenon by which all things with mass or energy are brought toward one another. Today, the phenomenon of gravity is explained by two theories: Newton’s law of universal gravitation and Einstein’s general relativity.
Flat-Earthers take the existence of the two explanations as inconsistency in science and use it as a “proof” of deliberate misconduct. Such allegation is obviously only a result of their prejudice. The two theories are the correct explanations of gravity, and can reliably predict the outcome of the phenomenon.
Continue reading “Theories of Gravity”
Buoyancy is an upward force exerted by a fluid (liquid or gas) that opposes the weight of an immersed object. Buoyancy happens because the fluid has a pressure gradient. Pressure gradient occurs because the fluid is affected by acceleration, such as the Earth’s gravitational acceleration.
Flat-Earthers makes buoyancy as an “explanations” on how things fall. They are wrong. Without Earth’s gravitational acceleration, buoyancy will not occur.
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A circumpolar star is a star, as viewed from a given latitude on Earth, that never sets below the horizon due to its apparent proximity to one of the celestial poles. Circumpolar stars stay up there in the sky, even during the day.
Flat-Earthers claim the Earth is stationary because the same stars are always visible in the sky. They are wrong. Only circumpolar stars are always in the sky. There are others that are not circumpolar. Some are only visible during certain times in a year.
Continue reading “Circumpolar and Non-Circumpolar Stars”
In the Northern hemisphere, the Sun appears to move to the right. In the Southern hemisphere, it appears to move to the left. During sunrise and sunset, the path of the Sun forms an angle that roughly corresponds to the latitude of the observer. This phenomenon occurs because observers on the different locations on Earth’s surface is not standing on the same plane.
The path of the Sun observed from many different locations on Earth’s surface is evidence of spherical Earth. This observation cannot possibly occur on a flat Earth.
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Gravity is not the only force. There are other forces, too. Multiple forces can simultaneously affect a single object. Forces can counteract gravity, making an object move against the direction of gravity. Such facts do not disprove gravity.
Flat-Earthers take the fact there are objects that move against the direction of gravity as ‘evidence’ of the non-existence of gravity. They are wrong. There are forces other than gravity affecting the object, having the opposite direction from gravity, with at least the same magnitude.
Continue reading “Countering Gravity”
Gravity is a natural phenomenon by which all things with mass or energy are brought toward each other. In 1687, Isaac Newton explained the phenomenon as a force, which was formulated in Newton’s law of universal gravitation.
Flat-Earthers insist that gravity does not exist. But this is only a result of a mere ignorance on how gravity works. Everything in our lives is consistent with what is explained in Newton’s law of universal gravitation.
Continue reading “Newton’s Law of Universal Gravitation”
Some people are confused that a full moon is visible all night, and think if the full moon is the result of the opposition of the moon from the sun, then a full moon should be visible only at midnight.
Flat-Earthers who have such spatial visualization problem take a step further and use it as ‘evidence’ that the Earth is not a sphere. They are wrong. The full moon phenomenon can easily be explained in the spherical Earth model.
Continue reading “Geometry of a Full Moon”
We cannot travel to another location by hovering inside a helicopter and wait for the Earth to rotate below us until we are above our destination. The reason is the phenomenon of inertia.
Flat-Earthers claim that we cannot do such a thing as ‘proof’ of a motionless Earth. They are wrong. When on the ground, the helicopter itself is already moving at the same velocity as Earth’s surface.
Continue reading “Helicopter and Earth’s Rotating Motion”
There are several models explaining the figure of the Earth. These models vary in the way they are used, in their complexity and in the accuracy with which they represent the size and shape of the Earth. These models are sphere, ellipsoid, and geoid.
Flat-Earthers often take the existence of these multiple models as evidence of disagreement among scientists, and that the shape of the Earth is still in contention. They are wrong. All these models are valid models, only with different complexity and accuracy.
Continue reading “The False Dilemma of the Figure of the Earth”
Most combustion engines work with oxygen from Earth’s atmosphere as its oxidizing agent in the combustion process. But in the case of rockets, there’s no oxygen in space. It would have to bring the oxidizer in addition to its fuel or use monopropellant which doesn’t require an oxidizer.
Flat-Earthers claim rockets should not be able to work in space because there’s no oxygen in space. They are wrong. The lack of oxygen in space is merely an engineering problem which is not impossible to solve. Rockets are engineered to carry its oxidizer or utilize monopropellant which does not require an oxidizer.
Continue reading “Rockets and the Lack of Oxygen in Space”
We often see flat-Earthers create a ‘miniaturized physical model’ of a real object and present them as ‘proof’ in support of flat-Earth and against spherical Earth. Their M.O. is to observe if the model remotely resembles the actual object in a particular way. If it does, then it is enough for them to conclude the model describe how the real object works.
Conversely, if a real object cannot be miniaturized and still have the same behavior as the original object, they would conclude that the behavior of the original object doesn’t exist.
They would wrongly call creating such models “doing an experiment”.
Continue reading “The so-called “Experiment” Done by Flat-Earthers”
Drag is a force acting opposite to the relative motion of an object moving with respect to a surrounding fluid. The higher the density of the fluid, the higher the magnitude of the drag.
Flat-Earthers claim that it is impossible for satellites to have such high speed. Usually, they would compare the speed of satellites to something like the SR-71 Blackbird, which holds the record as the fastest aircraft. They are wrong. At the altitude where satellites reside, the air density is several magnitudes smaller compared to near the surface, and thus, the drag experienced by satellites is also several magnitude smaller.
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“If the Earth is rotating, why when we throw a rock upward, it would fall to the original location?” The explanation is that the rock maintains the momentum before it is thrown. Before it is thrown, the rock has the same velocity as the surface of the Earth, it does not suddenly lose its momentum after being thrown, and there’s nothing exerting a force to alter its trajectory.
We usually use the moving vehicle analogy to illustrate this. If we throw the rock upward inside a moving vehicle, it would also fall to the original location, despite the fact that the vehicle is moving.
Flat-Earthers reject the analogy. Their usual excuse is that the atmosphere is not separated from space, and the rock is thrown “inside” the vehicle, separated by the body of the vehicle from the outside. They offer the analogy of being on the top of a moving vehicle as the correct analogy. They are wrong.
Continue reading “The Moving Vehicle Analogy”
An object falls down because of Earth’s gravitational attraction. But some denominations of flat-Earth insist that an object falls down due to its density, not gravity.
By putting two objects of an equal density and different mass against each other using a balance, we can easily determine that the density of the object is not the reason it falls down.
Continue reading “Density and the Balance Experiment”
Gravity is the attraction between objects with mass. The attraction is greater if the objects are more massive. The shape of the object practically doesn’t affect the magnitude of the attraction provided the objects are spaced far enough.
Flat-Earthers like to perform the ball-and-water ‘experiment’. They spray water to a ball, then observe the water does not stick to the ball the same way seawater stays on the surface of the Earth. They would conclude that ‘gravity does not exist’. They are wrong. The spherical shape of the Earth (and the ball)does not cause gravity, Continue reading “The Ball and Water ‘Experiment’”
Classical physics —like Newton’s law of motion, and Newton’s law of universal gravitation— has been superseded by Special Relativity, General Relativity, and Quantum Mechanics. But it doesn’t mean classical physics is wrong. Classical physics is still applicable when the parameters approach common, terrestrial values we use every day.
Pseudoscientists —including flat-Earthers— often misunderstood this and take the fact that classical physics is still being taught in schools as ‘proof’ of deception and the failure of modern science to explain the world. They are wrong.
Continue reading “Classical vs Modern Physics”