Stellar Aberration

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Stellar aberration is the apparent shift of stars about their actual positions, depending on the direction Earth is moving in its orbit around the sun. It occurs because the speed of light is finite; it takes time for light to reach the observer.

Stellar aberration was discovered in 1727 by James Bradley. It was the first direct proof of heliocentrism, that Earth is in orbit around the sun.

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Geocentrism: Incompatible with the Flat Earth Model

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Geocentrism is a superseded description of the universe with Earth at the center. Under geocentrism, celestial bodies all orbited Earth. Geocentrism was the accepted model of the Universe for approximately 18 centuries; before we knew that Earth orbits the Sun —or what we call as heliocentrism.

We often observe flat-Earthers using the arguments for geocentrism as if it supports the flat Earth model. They are wrong. Under geocentrism, the Earth is a sphere, located at the center of the universe. It is not remotely compatible with the flat Earth model, which is an even more archaic understanding of the Universe.

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An analemma is a photograph or diagram showing the position of the Sun in the sky, as seen from a fixed location on Earth at the same mean solar time, as that position varies over the course of a year. The diagram will resemble the figure 8.

The north-south component of the analemma results from the change in the Sun’s declination due to the tilt of Earth’s axis of rotation. The east-west component results from the non-uniform rate of change of the Sun’s right ascension, governed by the combined effects of Earth’s axial tilt and orbital eccentricity.

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Geocentric Coordinate System Does not Imply Geocentrism

In astronomy, a celestial coordinate system is a system for specifying positions of celestial objects like satellites, planets, stars, etc. The origin of the coordinate can be anywhere, including Earth. If the coordinate system is Earth-centered, we call it a geocentric coordinate system.

Flat-Earthers are often triggered by the term ‘geocentric’. They would search inside astronomy books and scientific journals to find the word ‘geocentric’. If they can find it, they would use the fact as ‘evidence’ of geocentrism, or that the Earth is the center of the universe, and the Sun is revolving around the Earth.

They are wrong. In many cases, the term ‘geocentric’ refers to the origin of a coordinate system. And it has nothing to do with whether the Sun revolves around the Earth or the other way around.

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The Galileo Affair was Never About the Shape of the Earth

Flat-Earthers often bring Galileo into the discussion. They treat him as a ‘villain’ who supported the spherical Earth but unable to prove it as he failed to demonstrate the occurrence of stellar parallax.

They are wrong. The Galileo affair was in fact not about the shape of the Earth at all. It was about geocentrism vs. heliocentrism. Everyone involved already knew that the Earth is spherical.

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‘The Principle’: A Documentary Without Principle

‘The Principle’ is a pseudoscientific documentary that promotes geocentrism, that the Earth is stationary and the center of the universe. Despite the fact that the film has almost nothing to do with flat-Earth, some flat-Earthers decide to use this film to bolster their beliefs. Because after all, in the flat-Earth model, the Earth is stationary and the center of the universe, right?

This actually gets more complicated than that. We are dealing with two forms of pseudoscience, that sometimes even goes against each other.

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