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WillowOne's Positions

Flat Earth

My Positions

  1. There is no flat Earth model that is consistent with observation.
  2. The model of the Earth as an oblate spheroid is aligned with every observable phenomenon, and I treat it as sufficiently true (see Knowledge for what I mean by that).

This note treats the question from the scientific side. See Positions/Conspiracy Theory/Flat Earth for the specific claims made by flat-earthers and why each fails.

Notes

  • An oblate spheroid is a sphere slightly flattened at the poles and bulging at the equator, in the Earth's case because of its rotation. The equatorial diameter is about 43 km greater than the polar diameter, a difference of around 0.3 per cent. For almost every practical purpose the Earth is a sphere.
  • I am not aware of any flat Earth model that adequately explains observed phenomena or is supported by credible evidence. The various flat models disagree with one another about basic features (the position and behaviour of the Sun, the nature of the "edge", what lies beneath), which is characteristic of a belief defined by what it rejects rather than by what it proposes.
  • There is overwhelming empirical evidence, spanning astronomy, physics, geodesy, navigation, and direct observation, that the Earth is not flat. Much of it has been available for over two thousand years:
  • Eratosthenes (c. 240 BC) measured the Earth's circumference from the difference in the Sun's angle at Syene and Alexandria, and got within a few per cent.
  • The Earth's shadow on the Moon during a lunar eclipse is always circular. Only a sphere casts a circular shadow from every angle.
  • Different stars are visible from different latitudes, and they are visible at angles that match a sphere, not a plane.
  • Ships disappear hull-first over the horizon, and the distance to the horizon increases with the observer's height exactly as a sphere predicts.
  • Time zones, the seasons, and the midnight sun in polar summer are all consequences of a rotating, tilted sphere and have no flat explanation.
  • Circumnavigation, by sea since 1522 and by air since 1924, works in every direction, including around Antarctica.
  • Gravity, as measured, varies with latitude and altitude in the way a rotating oblate spheroid predicts.
  • Since 1946 we have photographed it.
  • The persistence of flat Earth belief is a psychological and sociological question, not a scientific one. It tends to be a symptom of generalised distrust rather than a conclusion from evidence, and is therefore rarely corrected by evidence. See Knowledge on why a model is only changed by surprise, and why no surprise can be delivered by someone already cast as an enemy.

Also see