I’m working on a paper on Greek cosmology. I then wondered if the Greeks knew that the earth was round. I then searched the internet and found out that there were many philosophers who believed in a round earth. Aristotle had several arguments for this, but which were they exactly?
Answer
This was quite well known in Greek antiquity.
When a ship sails away, perpendicular to the coast, its image is seen not only shrinking, but also slowly disappearing, hull first, until only the upper sails are visible, which indicates the spherical shape of the sea surface.
Moreover, it was known that in more southerly regions other stars are visible, close to the horizon.
The final proof was provided by Eratosthenes who lived from 284 to 192 aCn, which is of course later than Aristotle (384-322 aCn), who determined the circumference of the earth by comparing the position of the sun on June 21 at noon in Alexandria and in Cyrene, a place south of Alexandria, on the Northern Tropic. So the sun was right there at that moment in the zenith, shining on the bottom of a deep well, a curious phenomenon which he knew well, having been born in Cyrene, and which probably gave him the idea of ​​his measurement.
Consult the Wikipedia article http://nl.wikipedia.org/wiki/Eratosthenes. The story of measuring the distance to Cyrene Alexandria by counting the day’s journeys of camels seems like a legend to me.
A modern researcher, Bruno Rossi, who analyzes the original texts, concludes that the determination was much more accurate and probably relied on existing measurements of the Nile Valley; The Egyptians were indeed the inventors of land surveying because every year, after the floods of the Nile, they had to redefine the boundaries of the fields.
Answered by
Prof. dr. French Cerulus
physics, especially classical theoretical mechanics, electromagnetism, quantum mechanics, history of physics .
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