Eratosthenes
Greek mathematician, geographer, poet, astronomer, librarian and music theorist / From Wikipedia, the free encyclopedia
Eratosthenes of Cyrene (276 ā 194 BC) was a 3rd century BC Greek mathematician, geographer and astronomer. He was head of the Library of Alexandria from 240 BC until his death: this was the most important library of the ancient world.
Eratosthenes | |
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Born | 276 BC Cyrene |
Died | 194 BC (Around 82) |
Occupations |
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Known for | Sieve of Eratosthenes Foundation of Geography |
According to the Suda,[1] his contemporaries nicknamed him Beta, (the second letter of the Greek alphabet), because he was the second best in the world in almost any field.[2] Eratosthenes was a friend of Archimedes, who also lived and worked in Alexandria. Archimedes was the greatest mathematician and inventor of the age, so perhaps the Beta nickname was not unjust.
The works Eratosthenes wrote are known to us only indirectly: the great Library was destroyed, and no copies survived. Strabo (~63BCā24AD) wrote about geography in antiquity. He tells us that the works of Eratosthenes were On the measurement of the Earth and Geographica.
Eratosthenes made several remarkable discoveries and inventions. He was the first person to calculate the circumference of the Earth (with remarkable accuracy), and he invented a system of latitude and longitude. He calculated the tilt of the earth's axis (again with remarkable accuracy); he may also have accurately calculated the distance from the earth to the sun and invented the leap day.[3] He created a map of the world based on the available geographical knowledge of the era. Eratosthenes was also the founder of scientific chronology; he wanted to fix the dates of the chief literary and political events from the conquest of Troy.