He recognized the Nile's source was a lake, and that rains in the lake region caused the Nile to flood. Chief among these is the calculation of the circumference of the earth and the development of a mathematical sieve named after him. At Alexandria, the angle of inclination of the sun was about 7 degrees. He was the first person to calculate the circumference of the Earth (with remarkable accuracy), and he invented a system of latitude and longitude. Eratosthenes facts for kids. 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. The measure of Earth's circumference is the most famous among the results obtained by Eratosthenes, who estimated that the meridian has a length of 252,000 stadia, with an error on the real value between −2.4% and +0.8% (assuming a value for the stadion between 155 and 160 metres). This page was last modified on 8 October 2020, at 22:20. Born: c. 276 BCE in Cyrene … The sieve of Eratosthenes. Assuming that Alexandria was due north of Syene he concluded that the distance from Alexandria to Syene must be 1/50 of the total circumference of the Earth (360 degrees). Eratosthenes measured the circumference of the Earth without leaving Egypt. Gill is a Latinist, writer, and teacher of ancient history and Latin. He suggested that calendars should have a leap day every fourth year, an idea taken up two centuries later by Julius Caesar. Eratosthenes, in full Eratosthenes of Cyrene, (born c. 276 bce, Cyrene, Libya—died c. 194 bce, Alexandria, Egypt), Greek scientific writer, astronomer, and poet, who made the first measurement of the size of Earth for which any details are known. He pursued higher education from Athens where he was taught by the best teachers of the day. He was head of the Library of Alexandria from 240 BC until his death: this was the most important library of the ancient world. He rounded the result to a final value of 700 stadia per degree, which implies a circumference of 252,000 stadia. The common Attic stadium was about 185 metres (607 feet), which would imply a circumference of 46,250 kilometres or 28,740 miles, which is 6,250 kilometres (3,880 miles) different from the currently accepted circumference of the Earth (40,000 kilometres or 25,000 miles). [4] His estimated distance between the cities was 5000 stadia (925 kilometres or 575 miles) by estimating the time that he had taken to travel from Syene to Alexandria by camel. Eratosthenes was a friend of Archimedes, who also lived and worked in Alexandria. Eratosthenes measured the circumference of the Earth without leaving Egypt. The method is an early application of trigonometry in the measurement science of geodesy. By using this site, you agree to the Terms of Use Privacy Policy. He also wrote the fundamentals of astronomy in a poem called Hermes. Eratosthenes of Cyrene (276 – 194 BC) was a 3rd century BC Greek mathematician, geographer and astronomer. She has been featured by NPR and National Geographic for her ancient history expertise. He also deduced the length of the year as 365¼ days. Eratosthenes was responsible for bring to notice some of the most important discoveries in geography, astronomy and mathematics. Eratosthenes is reported to have starved himself to death at Alexandria in 194 B.C. Content is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. His most famous calculation, in the now lost treatise On the Measurement of the Earth, explains how he compared the shadow of the sun at Summer Solstice noon in two places, Alexandria and Syene. He was head of the Library of Alexandria from 240 BC until his death: this was the most important library of the ancient world. The works Eratosthenes wrote are known to us only indirectly: the great Library was destroyed, and no copies survived. Eratosthenes is famous for many things, including a mapping method that used latitudes and longitudes, and his accurate computation of the circumference of earth. Assuming that Alexandria was due north of Syene he concluded that the distance from Alexandria to Syene must be 1/50 of the total circumference of the Earth (360 degrees). [3] He created a map of the world based on the available geographical knowledge of the era. Fast Facts: Eratosthenes Known For: Eratosthenes was a Greek polymath who became known as the father of geography. The sieve was described and attributed to Eratosthenes in the Introduction to Arithmetic by Nicomachus. Strabo (~63BC–24AD) wrote about geography in antiquity. Eratosthenes went further and computed the tilt of the Earth's axis to within a degree. [7] It works efficiently for the smaller primes (below 10 million). The common Attic stadium was about 185 m, which would imply a circumference of 46,620 km, which is 16.3% too large. The Prime Glossary: "The Sieve of Eratosthenes", https://web.archive.org/web/20070205033538/http://traianus.rediris.es/topo01/surveying.pdf, "How did Eratosthenes measure the circumference of the earth? 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. Other discoveries and inventions. This is the tilt which is the main cause of the annual climate cycle of spring, summer, autumn, winter. This is the tilt which is the main cause of the annual climate cycle of spring, summer, autumn, winter. 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 was called "Beta" (the second letter of the Greek alphabet) because he was never first, but he is more famous than his "Alpha" teachers because his discoveries are still used today. Eratosthenes made several remarkable discoveries and inventions. Archimedes was the greatest mathematician and inventor of the age, so perhaps the Beta nickname was not unjust. He also knew, from measurement, that in Alexandria, the angle of elevation of the sun would be 1/50 of a full circle (7°12') south of the zenith at the same time. ThoughtCo uses cookies to provide you with a great user experience. He tells us that the works of Eratosthenes were On the measurement of the Earth and Geographica. He also deduced the length of the year as 365¼ days. Measuring the Earth's circumference. ), a mathematician, is known for his mathematical calculations and geometry. The sun shone directly into a well at Syene at noon. He knew that on the summer solstice at local noon at the city now called Aswan on the Tropic of Cancer, the sun would appear at the zenith, directly overhead. According to the Suda, 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. It works efficiently for the smaller primes (below 10 million). [8] In an updated... • In about 240 BC Eratosthenes calculated Earth’s size with good accuracy. By using ThoughtCo, you accept our, Eratosthenes Calculates the Circumference of the Earth, Biography of Eratosthenes, Greek Mathematician and Geographer, Famous People Who Worked at the Ancient Library of Alexandria, Inventions and Discoveries of Ancient Greek Scientists, Claudius Ptolemy: Astronomer and Geographer from Ancient Egypt, Euclid of Alexandria and His Contributions to Geometry, Aristarchus of Samos: An Ancient Philosopher With Modern Ideas, Ancient Egypt: Birthplace of the Modern Calendar, Geodesy and the Size and Shape of the Planet Earth, The Ptolemies: Dynastic Egypt From Alexander to Cleopatra, M.A., Linguistics, University of Minnesota. Eratosthenes (c.276 to 194 B.C. N.S. The works Eratosthenes wrote are known to us only indirectly: the great Library was destroyed, and no copies survived. 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. He rounded the result to a final value of 700 stadia per degree, which implies a circumference of 250,000 stadia. Eratosthenes was a prominent Greek mathematician, astronomer and geographer who lived between 276 BC and 194 BC. ), a mathematician, is known for his mathematical calculations and geometry. His work helped lay the foundation for many of the brilliant advanced concepts in math and Eratosthenes made several remarkable discoveries and inventions. [5][6] The method is an early application of trigonometry in the measurement science of geodesy. Eratosthenes of Cyrene (276 – 194 BC) was a 3rd century BC Greek mathematician, geographer and astronomer. The sieve was described and attributed to Eratosthenes in the Introduction to Arithmetic by Nicomachus. Eratosthenes of Cyrene (276 BC–194 BC) was a third century BC Greek mathematician, geographer and astronomer. Born in the Cyrene, the young lad was remarkably curious from an early age. Eratosthenes described his technique in a book entitled On the measure of the Earth, which has not been preserved. By comparing the shadow of the sun at Summer Solstice noon at Alexandria and Syene, and knowing the distance between the two, Eratosthenes calculated the circumference of the earth. His estimated distance between the cities was 5000 stadia (about 500 geographical miles or 800 km) by estimating the time that he had taken to travel from Syene to Alexandria by camel. However, if we assume that Eratosthenes used the "Egyptian stadium" of about 157.5 m, his measurement turns out to be 39,375 km, an error of less than 1%. Much of what Eratosthenes wrote is now lost, including a geometrical treatise, On Means, and one on the mathematics behind Plato's philosophy, Platonicus. Eratosthenes wrote a Geographica based on his calculations of the circumference of the earth. The exact size of the stadion he used is frequently argued. In mathematics, the sieve of Eratosthenes (Greek: κόσκινον Ἐρατοσθένους) is a simple, ancient algorithm for finding all prime numbers up to a specified integer. Archimedes was the greatest mathematician and inventor of the age, so perhaps the Beta nickname was not unjust. He knew that on the summer solstice at local noon at the Syene on the Tropic of Cancer, the sun would appear at the directly overhead. He created a map of the world based on the available geographical knowledge of the era. He tells us that the works of Eratosthenes were On the measurement of the Earth and Geographica. Measuring the Earth's circumference. In mathematics, the sieve of Eratosthenes (Greek: κόσκινον Ἐρατοσθένους) is a simple, ancient algorithm for finding all prime numbers up to a specified integer. He also knew, from measurement, that in Alexandria, the angle of elevation of the sun would be 1/50 of a full circle (7°12') south of the zenith at the same time.