Eratosthenes calculates the circumference of Earth


Lerner KL. Eratosthenes calculates the circumference of Earth. DRAFT COPY subsequently published in Science and Its Times: Understanding the Social Significance of Scientific Discovery. Thomson Gale. 2001.
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Of increasing importance in ancient and classical civilizations that had their territorial and cultural horizons consistently expanded by the march of armies and the alluring promise of wealth and trade, was the measurement of distance. Using elegant mathematical reasoning and limited empirical measurement, in approximately 240 B.C., Eratosthenes of Cyrene (now located in Libya) made an accurate measurement of the circumference of the Earth. In addition to providing evidence of scientific empiricism in the ancient world, this and other contributions to geodesy (the study of the shape and size of the Earth) spurred subsequent exploration and expansion. Ironically, centuries later the Greek mathematician and astronomer Claudius Ptolemy's erroneous rejection of Eratosthenes' mathematical calculations, along with other mathematical errors, resulted in the mathematical estimation of a smaller Earth that, however erroneous, made extended seagoing journeys and exploration seem more tactically achievable.


Last updated on 07/08/2019