Eratosthenes was an ancient greek astronomer, geographer, and mathematician. Eratosthenes was a greek scientific writer, astronomer, and poet, who is credited with making the first approximation of the size of the earth for which any details are know. His work helped lay the foundation for many of the brilliant advanced concepts in math and science in the modern era. Eratosthenes was a famous greek philosopher, mathematician and geographer who is credited for the measurement of earths circumference. After studying in alexandria and athens, he settled in alexandria around 255 bc and became director of the great library there. This is the first modern edition and first english translation of one of the earliest and most important works in the history of geography, the thirdcentury geographika of eratosthenes. His only surviving work is catasterisms, a book about constellations.
True, not a lot is known about eratosthenes himself. It seems that he was not regarded by his contemporaries as a top rank mathematician. In this work, which for the first time described the geography of the entire inhabited world as it was then known, eratosthenes of kyrene ca. The idea is to begin by listing all the natural numbers bigger than 2. At some period during his early manhood he went to athens for the ancient. He was a librarian, geographer, mathematician, astronomer, historian, and poet. Educated in athens, greece, and in alexandria, egypt, eratosthenes was appointed director of the great library at alexandria in 236 b. Eratosthenes of cyrene was a greek mathematician who lived from about 275195 b. Eratosthenes created a calendar with leap years, and he also worked as a historian to give dates for past events in greek history. Eratosthenes was the first person to use the word geography and other geographical terms that are still in use today, and his efforts to calculate the circumference of the earth and the distance from the earth to the sun paved.
Eratosthenes is famous for making the first good measurement of the size of the earth. Eratosthenes of cyrene if youre seeing this message, it means were having trouble loading external resources on our website. He was head of the library of alexandria from 240 bc until his death. After striking out the number 1, simply strike out every second number following the number 2, every third number following the number 3, and continue in this manner to strike out every nth number following the number n. Search through the entire ancient history timeline. Eratosthenes biography life of greek mathematician. Eratosthenes was educated in philosophy and mathematics in athens. Sieve of eratosthenes sieve of eratosthenes is an almost mechanical procedure for separating out composite numbers and leaving the primes.
Eratosthenes was a mathematician from ancient greece. Eratosthenes geography by eratosthenes, hardcover barnes. Specify between which dates you want to search, and what keywords you are looking for. Eratosthenes of cyrene 276 bc194 bc was a third century bc greek mathematician, geographer and astronomer. History questions could well be appropriate here, but its unclear to me what the reason is for believing that euclid and eratosthenes are the same. However, it was in geography where he proved to be more skillful for he was one of the greatest of all ancient geographers. Eratosthenes was the third librarian at the famous library of alexandria. Read on to know more about his childhood, career, profile and timeline. This month in physics history aps physics aps home. Eratosthenes simple english wikipedia, the free encyclopedia. Today he is best known for his contributions to geography, mathematics, and astronomy. Eratosthenes biography childhood, life achievements. Modern scholars disagree about the length of the stadium used by eratosthenes.
Sieve of eratosthenes, systematic procedure for finding prime numbers that begins by arranging all of the natural numbers 1, 2, 3, in numerical order. Eratosthenes was an ancient greek scientist born in the town of cyrene in about 276 bc. Constellation myths by eratosthenes and a great selection of related books, art and collectibles available now at. Eratosthenes was born in cyrene presentday libya and became the librarian at alexandria during the second half of the third century b. Maybe in 2000 years someone might think that weyl, weil and wiles were all the same mathematician after all, in the distant future it might seem incomprehensible why one of them couldnt as well. To this day, a number of greek mathematicians are considered for their innovations and influence on mathematics. That mathematical method is now called the sieve of eratosthenes. Nicholas nicastro brings to life one of history s greatest experiments when an ancient greek named eratosthenes first accurately determined the distance around the spherical earth. According to the great greek astronomer and mathematician hipparchus, who was born within a few years of eratosthenes death, eratosthenes invented the armillary sphere. Carl sagan on ancient greek mathematician eratosthenes. His best known mathematical accomplishment was the first accurate calculation of.
Sometime in the middle of his life eratosthenes became a mathematician, geographer, and scientist and made the discoveries he is most well known for. Eratosthenes is famous for many things, including a mapping method that used latitudes and longitudes, and his accurate computation of the circumference of earth. Circumference is the story of what happened when one man asked himself that very question. Eratosthenes was a mathematician and astronomer from greek antiquity. Eratosthenes born276 bc cyrene died194 bc alexandria ethnicity.
Strabo quoted eratosthenes extensively in his own first and second books, and throughout his work, providing. But as the author says in his introduction, that doesnt stop people from writing books about obscure but significant figures. He was born in what is now libya, to parents who were probably chaldean. The greeks were the earliest discoverers of much of the knowledge that went on to lay the foundations of scientific studies for. Cyrene is what we would today recognize as libya, and there he earned a. Life of eratosthenes, ancient greek alexandrian scholar, native of cyrene and one of the greatest geographers in antiquity. He also served as a distinguished and innovative geographer. For eratosthenes shows that the perpendicular distance from the highest mountain tops to the lowest regions is ten stades c. He was a man of learning, becoming the chief librarian at the library of alexandria. At the same time in alexandrea, 500 miles north on the same meridian, the. Eratosthenes is the ancient greek mathematician and geographer attributed with devising the first system of latitude and longitude.
He lived and worked for most of his life in the city of alexandria in egypt. Luckily, other scholars have recorded his wideranging work. Eratosthenes was the first person to use the word geography and other geographical terms that are still in use today, and his efforts to calculate the circumference of the earth and the distance from the earth to the sun paved the way for our. This is because he was considered the second best in so many fields. This is a facsimile of the map he produced based on his calculations. Eratosthenes was born in the year 276 bc to aglaos and his wife. Eratosthenes was the second person to be head librarian there. Read and learn for free about the following article. He was to become the third chief librarian of the great library of alexandria, the centre of science and learning in the ancient world. The earth is the solid sphere at the center of the device. Besides figuring out the size of the earth, eratosthenes made several other important inventions and discoveries. He studied under the stoic philosopher zeno, ariston, lysanias, and the poetphilosopher callimachus.
In mathematics, eratosthenes discussed doubling a cube and is thought to have worked to find a solution. The sieve of eratosthenes is a method for find prime numbers that is attributed to the ancient greek mathematician eratosthenes. Eratosthenes then used this to calculate the circumference of the earth to be about 250,000 stadia. Discrete mathematicssieve of eratosthenes wikibooks, open. Eratosthenes spent most of his career at the worldrenowned library of alexandria. 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 timeline ancient history encyclopedia. To navigate the timeline, click and drag it with your mouse, or click on the timeline overview on the bottom. Cyrene, then a greek city, is now the town of shahhat in libya. At the same time in alexandria 500 miles north on the same meridian, the rays of the sun shone at an angle of 7. The actual calculations that the great eratosthenes would employ were quite simple.
He was also the first know person to calculate the circumference of the earth. Values between 500 and about 600 feet have been suggested, putting eratosthenes calculated circumference between about 24,000 miles and about 29,000 miles. Map of a facsimile of the world map by eratosthenes around 220 bc. Eratosthenes 276195 bce was an ancient greek alexandrian scholar, native of cyrene, who attained distinction in many fields including philosophy, mathematics, astronomy and history. An armillary sphere from a painting by sandro botticelli in about 1480. Cyrene is what we would today recognize as libya, and there he earned a great deal of fame due. Nov 03, 2009 the greek mathematician eratosthenes ca. After striking out the number 1, simply strike out every second number following the number 2, every third number following the number 3, and. Discrete mathematicssieve of eratosthenes wikibooks. He noted that the suns rays fell vertically at noon in syene now aswan, egypt, at the summer solstice. In astronomy he also calculated the angle that the earths axis is tilted on. He spent most of his life in the city of alexandria in egypt. Eratosthenes is most famous for making the first accurate measurement of the circumference of the earth. His friends at the library nicknamed him pentathlos, or athlete who competes in five different events.
Eratosthenes also worked as a tutor of ptolemys son. In number theory, he introduced the sieve of eratosthenes, an efficient method of identifying prime numbers. He noticed that on a certain day the sun shone directly down a deep well in syene modern aswan. Eratosthenes went to the then seat of learning in athens for his education and was taught by the best teachers of the day.
In alexandria, also in egypt, at the same date and time, sunlight fell at an angle of about 7. Circumference is the best kind of popular science book, the kind that doesnt skimp on substance, yet helps even the most casual reader grasp its subject. The image above is from a painting by bernardo strozzi in the year 1635, nineteen centuries. Eratosthenes 276 bc 194 bc was a greek mathematician, geographer and astronomer with probably chaldean origins. Apostol 19232016 professor of mathematics in california institute of technology, he has authored a. He was also active in the fields of astronomy, geography, music, and poetry. Eratosthenes, greek scientific writer, astronomer, and poet, who made the first measurement of the size of earth for which any details are known. His mathematical work is known principally from the writings of the greek geometer pappus of alexandria, and his geographical work from the first two books of the geography of the greek geographer strabo. Eratosthenes wrote a geographica based on his calculations of the circumference of the earth. The work of eratosthenes would have a profound effect on the work roughly 1500 years later. Eratosthenes of cyrene was a greek born about 276 bce and died around 194 bce. He was also the director of the library of alexandria. It was invented by the greek scientist and mathematician eratosthenes who lived approximately 2,300 years ago.
Eratosthenes was a prominent greek mathematician, astronomer and geographer who lived between 276 bc and 194 bc. Makers of mathematics eratosthenes 276 194 bce eratosthenes was born in cyrene modernday libya. Eratosthenes of cyrene 276 194 bc was a 3rd century bc greek mathematician, geographer and astronomer. Popular science communicator carl sagan presents the many incredible discoveries made by ancient greek mathematician eratosthenes. Eratosthenes measured earths circumference mathematically using two surface points to make the calculation. After study in alexandria and athens, eratosthenes settled in alexandria about 255 bce and became director of the great library there. Eratosthenes was a greek scientist who lived from 276 to 194 b. In comparison with the great size of the earth the protrusion of mountains is not sufficient to deprive it of its spherical shape or to invalidate measurements based on its spherical shape.
Prof bela bollobas 1963, explains the significance of indian mathematician. He was born in cyrene now shahhat, libya and died in ptolemaic alexandria. Eratosthenes was the first person to use the word geography and other geographical terms that are still in use today, and his efforts to calculate the circumference of the earth and the distance from the earth to the sun paved the way for our modern understanding of the cosmos. In a sense, he had too since most modern mathematical languages had yet to be invented.
Eratosthenes was the founder of scientific chronology. His best known mathematical accomplishment was the first accurate calculation of the earths circumference. Eratosthenesgeographikawas a modest work, only three books in length. In historical times, greek civilization has played one of the major roles in the history and development of mathematics.