Wednesday, February 20, 2008

One of the legends of popular culture is that prior to Columbus most European people believed in a "flat Earth". In actual fact almost all educated people from antiquity on knew very well that the Earth was spherical. This belief is often atributed to the philosopher and mathematical Pythgagoras, orginator of the 'Pythagoran theorum' (a squared plus b squared equals c squared in a right angle triangle), the bane of all of us who had to endure the usual Catholic education that included geometry. Try and prove it, rather than memorize it. Pythagoras is also often credited with "proving" that the Earth is round by observing the shape of the shadow of the Earth on the Moon during a lunar eclipse. This is pretty much apocryphal as whatever reports of Pythagoras' reasonings that have survived (none of the original writings have) says that he "proved" the Earth's spherical shape by merely "reasoning" that a sphere was a more "perfect shape". It was Aristotle who later refined the reasoning of the shape of the Earth's shadow on the Moon(amongst his other reasons for assuming a spherical Earth) to prove that the Earth was a sphere rather than a simple circular disc. The "perfection of the sphere" was part and parcel of the later geocentric system devised by Ptolemy, a model that lasted until Copernicus and Galileo when it was replaced by a heliocentric model. Aristotle was more the originator (and certainly the refiner) of the proof of a spherical Earth than Pythagoras ever was. It is a popular myth that Europeans before Columbus, or at least those who were educated, believed in a "flat Earth".

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