10 EURO SILVER COIN PROOF ERATOSTHENES

Περιγραφή

Eratosthenes (276–194 BC) was a mathematician, geographer, and astronomer. He was born in Cyrene, in present-day Libya, and lived in Alexandria, where Ptolemy III appointed him director of the Library of Alexandria. His most famous scientific achievement is the calculation of the circumference of the Earth. Through a brilliant experiment—still repeated every year by students around the world—he calculated it at 252,000 stadia, with a margin of error between –2.4% and +0.8% from the true value (40,075 km), depending on the length of the stadium (155–160 meters) he used. He also calculated the distance of the Moon and the Sun from the Earth, once again with remarkable accuracy. Eratosthenes was the first to attempt to establish a scientific system of chronology, using the Trojan War as a starting point, in his works Chronographiai and Olympionikai. Another important work of his was Geographika, and it is said that he himself coined the term “geography.” In astronomy, his most significant work was the Catasterisms.