Biography of Eratosthenes, Greek mathematician and geographer

Eratosthenes was born in the year 276 BC. C. in Cyrene, in present-day Libya. His father’s name was Aglaos. He conducted his studies in Athens and the Egyptian city of Alexandria.He was a disciple of important wise men of his time, such as Ariston of Chios, Lisanias of Cyrene, Callimachus and Archimedes.

In the year 236 a. C., the Egyptian pharaoh Ptolemy III summoned him to be in command of the Library of Alexandria, since he held until his death.

Eratosthenes possessed a wide variety of knowledge and aptitude for study. In fact, he was an astronomer, poet, geographer and philosopher. He even called it by the name of Pentathlos , a title that was reserved for the winning athlete in the five competitions of the Olympic Games; that is, he excelled in various disciplines, even though he was not the best in each of them. Various authors affirm that he was also given the nickname of Beta , the second letter of the Greek alphabet, because he ranked second in all the branches of science to which he dedicated himself.

His studies and scientific contributions led him to be considered as another Plato. In addition, Eratosthenes is one of the most remembered figures for having been the librarian responsible for the Library of Alexandria, which was the largest record of ancient knowledge.

discoveries and achievements

Eratosthenes dedicated his life to study and achieved a wide variety of achievements in the scientific disciplines he studied. His most important achievements were:

• He invented the first map of the world. There he represented all that was known of geography up to that time, including the extent of the Nile River, and the region of Eudamion, present-day Yemen, in Arabia.
• He wrote a treatise entitled “Geography” which was the first time this word was used. In his work he introduced concepts that are still current, such as climatic zones.
• He achieved the creation of one of the most advanced calendars for his time, as well as a chronological history of the world since the Trojan War.
• He invented the concept of the leap year. He discovered that a year is slightly longer than 365 days, requiring an extra day to be added to the calendar every four years to keep it constant.
• He invented an algorithm known as the Eratosthenes sieve, which is used to identify prime numbers.
• He was the first to calculate, with considerable precision, the circumference of the Earth. This he did by using a method of trigonometry, which was what brought him fame.
• He invented the armillary sphere, an instrument that made it possible to demonstrate in a palpable way the movement of the stars around our planet.
• He created the method that was baptized as the Eratosthenes Sieve, by which he calculated the prime numbers.
• He came to the conclusion that the curved line that goes around the planet Earth, called the ecliptic, is oblique. He also tried to determine its degree of obliquity.

Death

At the end of his years he was stricken with terrible blindness and starved to death in 194 BC in Alexandria. Legend has it that he starved to death because he couldn’t read. Some sources maintain that he died at the age of 80, however, others claim that he passed away at the age of 82.

Undoubtedly, Eratosthenes was one of the greatest Greek scholars, and his work influenced fields ranging from mathematics to geography. Due to his great legacy and contribution to knowledge, a crater on the Moon was named in his honor.

Bibliography

• Lozano Leyva, M. From Archimedes to Einstein. (2012). Spain. Pocket-size.
• Eratosthenes. geography . (2010). USA. Princeton University Press.