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Airy's failure

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In 1871, astronomer Sir George Biddell Airy (1801–1892) conducted an experiment, the purpose of which was to test the aether drag hypothesis by detecting change in the stellar aberration. This experiment has been widely misquoted by flat-earthers as a proof of Earth being stationary.

The experiment[edit]

Stellar aberration results from Earth's movement. Airy's original paper states the following:

A discussion has taken place on the Continent, conducted partly in the 'Astronomische Nachrichten,’ partly in independent pamphlets, on the change of direction which a ray of light will receive (as inferred from the Undulatory Theory of Light) when it traverses a refracting medium which has a motion of translation. The subject to which attention is particularly called is the effect that will be produced on the apparent amount of that angular displacement of a star or planet which is caused by the Earth’s motion of translation, and is known as the Aberration of Light.
—George Biddell Airy (1871)

Translation is the movement the Earth makes around the Sun,[1] so Airy already knew Earth was moving through space.

Airy filled a 35.3 inch telescope with distilled water, which slowed the speed of light from 300,000km/h to 225,000km/h, i.e., by 25%. This gave aether wind more time to cause drift. Airy pointed the telescope towards γ Draconis, which was slightly less than 100 arcseconds (0.0278 degrees) from zenith.

As said above, the goal was to detect change in the stellar aberration. As the telescope was pointed at zenith, the stellar aberration required deviation of 19.8 arcseconds.[2] I.e., Airy expected the aether to cause additional change in light's angle due to the aether wind. However, as he states in the paper:

Remarking that the mean results for Geographical Latitude of the Instrument (determined from observations made when the Aberration of the star had respectively its largest + value and its largest — value) agree within a fraction of a second, I think myself justified in concluding that the hypothesis of Professor Klinkerfues is untenable.
—George Biddell Airy (1871)

Thus, Airy failed to detect aether wind. As stellar aberration had already shown Earth to move, Airy's experiment showed that either aether moves with Earth, or, that aether does not exist.

The bitching and whining from flat-earthers[edit]

In his video Eric Dubay described the experiment as follows:

The purpose of this test was to detect the Earth's movement. Contrary to its objective, the outcome demonstrated that the stars moved relative to a motionless Earth. For this test, Airy filled the telescope with water which is known to slow down the speed of light. He then planned to calculate the necessary tilt to align the telescope so starlight could travel directly down the tube. Unexpectedly, Airy found that the light entered the telescope at the correct angle, without need to adjust the tilt, demonstrating an absence of Earth's horizontal movement.

The purpose was not do detect Earth's movement. It was already known at that point. The purpose was to detect aether wind. The experiment demonstrated that either the Earth dragged aether along, or that aether did not exist.

Dubay also lied by omission, by claiming Earth was stationary because no tilt needed to be added. As was seen above, Airy had already factored in the 19.8 arcsecond tilt to account for stellar aberration that resulted from Earth's movement. What Airy did not have to do, was add more tilt to compensate for aether wind, which is sort of expected, given that — as humanity would soon learn — aether does not exist.

In another video Dubay lied about the name "Airy's failure" to result from "because it failed to disprove heliocentrism". Again, the name comes from failure to detect aether wind.

References[edit]