1. Eratosthenes Branch of Science " Astronomers Branch of Science " Geographers Branch of Science " Philosophers Branch of Science " Scholars Nationality " Greek eratosthenes of cyrene (ca. 284ca. 192 BC) Consummate Greek scholar whose status as second best http://www.math.utah.edu/~alfeld/Eratosthenes.html

Peter Alfeld, Department of Mathematics, College of Science University of Utah Eratosthenes of Cyrene A versatile scholar, Eratosthenes of Cyrene lived approximately 275-195 BC. He was the first to estimate accurately the diameter of the earth. For several decades, he served as the director of the famous library in Alexandria. He was highly regarded in the ancient world, but unfortunately only fragments of his writing have survived. Eratosthenes died at an advanced age from voluntary starvation, induced by despair at his blindness. Here are some links to Eratosthenes related web pages: A worldwide experiment based on Eratosthenes original computation of the Earth's circumference. A page on Ancient Geography. Maps, lists, resources, and links pertaining to ancient Greek mathematics. The library of Alexandria.

2. Eratosthenes Of Cyrene eratosthenes of cyrene. 5/4/99 http://www.hsu.edu/faculty/worthf/mathematicians/Eratosthenes

Eratosthenes of Cyrene Click here to start Table of Contents Eratosthenes of Cyrene Eratosthenes Author: Fred Worth Email: worthf@hsu.edu Home Page: http://www.hsu.edu/faculty/worthf/mathematicians

3. Encyclopædia Britannica Encyclopædia Britannica. eratosthenes of cyrene. Encyclopædia Britannica Article http://www.britannica.com/eb/article?eu=33437

4. The Eratosthenes Project The Eratosthenes Project The Original Experiment eratosthenes of cyrene (275194 B.C.) was a Greek scholar who lived and worked in Cyrene and Alexandria. http://www.phys-astro.sonoma.edu/observatory/eratosthenes

The Eratosthenes Project The Original Experiment Some Deatils Our Experiment The Project Observations ... Project Results The Original Experiment Eratosthenes of Cyrene (275-194 B.C.) was a Greek scholar who lived and worked in Cyrene and Alexandria. Eratosthenes was director of the famous library in Alexandria, and is known for numerous important contributions to mathamatics, geography, and astronomy. In particular, he is remembered for a technique he introduced which enabled him to compute the first reliable determination of the true size of the earth. This technique is based on the observation by Eratosthenes that the sun is directly overhead at noon in Syene in southern Egypt on the first day of summer. (This is the time of the summer solstice.) While visiting Syene Eratosthenes apparently stopped at a well and noted that the noon sun reflected directly back from the water in the bottom of the well. Since Eratosthenes knew that the earth was a sphere, he correctly reasoned that if he could determine the altitude of the noon sun at some other location on the first day of summer, AND if he knew the distance between these two locations, he could compute the circumference of the earth as a simple ratio. This principle is illustrated in the following illustration, along with a sketch of a reconstructed map of the world as known by Eratosthenes. The Eratosthenes Technique for Determining the Size of the Earth When Eratosthenes returned to Alexandria, being a good astronomer, he knew he could wait until next year on the first day of summer and measure the altitude of the noon sun. Then since he had kept track of how far he had traveled from Syene to Alexandria, he could determine the circumference and the diameter of the earth.

5. Eratosthenes eratosthenes of cyrene A postulate of spherical astronomy is that the Earth is a small point in relation to the heavenly bodies. From this Eratosthenes reasoned the Sun's rays strike the Earth parallel over its entire surface. http://share2.esd105.wednet.edu/jmcald/Aristarchus/eratosthenes.html

Eratosthenes of Cyrene A postulate of spherical astronomy is that the Earth is a small point in relation to the heavenly bodies. From this Eratosthenes reasoned the Sun's rays strike the Earth parallel over its entire surface. Working in Syene and Alexandria, which Eratosthenes assumed were on the same meridian, he estimated the distance between the cities to be about 5,000 stades (a stade is believed to be about 559 feet - approximately one-tenth of a mile). At summer solstice, at noon, the Sun cast no shadow in Syene, but in Alexandria a shadow was visible. Using a gnomon (a vertical stick), Eratosthenes measured the shadow's angle to be about one-fiftieth of a circle. Using this result, r = 39,788.7 stades = 22,241,883.3 feet = 4,212.5 miles (The actual radius of the Earth is 3,963.21 miles) Using the work of Aristarchus with that of Eratosthenes we find: The radius of the Moon is, (The actual radius of the Moon is 1,080 miles) Since the radius of the Sun is, miles (The actual radius of the Sun is approximately 433,200 miles) Home History Half-Moon Solar Eclipse ... Apparent Diameter

6. Eratosthenes eratosthenes of cyrene. Thus may it be, and let any one who sees thisoffering say This is the gift of eratosthenes of cyrene . http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Eratosthenes.html

Eratosthenes of Cyrene Born: 276 BC in Cyrene, North Africa (now Shahhat, Libya) Died: 194 BC in Alexandria, Egypt Click the picture above to see a larger version Previous (Chronologically) Next Biographies Index Previous (Alphabetically) Next Main index Eratosthenes was born in Cyrene which is now in Libya in North Africa. His teachers included the scholar Lysanias of Cyrene and the philosopher Ariston of Chios who had studied under Zeno, the founder of the Stoic school of philosophy. Eratosthenes also studied under the poet and scholar Callimachus who had also been born in Cyrene. Eratosthenes then spent some years studying in Athens. The library at Alexandria was planned by Ptolemy I Soter and the project came to fruition under his son Ptolemy II Philadelphus. The library was based on copies of the works in the library of Aristotle . Ptolemy II Philadelphus appointed one of Eratosthenes' teachers Callimachus as the second librarian. When Ptolemy III Euergetes succeeded his father in 245 BC and he persuaded Eratosthenes to go to Alexandria as the tutor of his son Philopator. On the death of Callimachus in about 240 BC, Eratosthenes became the third librarian at Alexandria, in the library in a temple of the Muses called the Mouseion. The library is said to have contained hundreds of thousands of papyrus and vellum scrolls. Despite being a leading all-round scholar, Eratosthenes was considered to fall short of the highest rank.

7. Chronology For 500BC To 1AD About 235BC eratosthenes of cyrene estimates the Earth's circumferencewith remarkable accuracy finding a value which is about 15% too big. http://www-gap.dcs.st-and.ac.uk/~history/Chronology/500BC_1AD.html

Chronology for 500BC to 1AD Previous page Chronology index Full chronology Next page About 500BC The Babylonian sexagesimal number system is used to record and predict the positions of the Sun, Moon and planets. (See this History Topic About 500BC Panini 's work on Sanskrit grammar is the forerunner of the modern formal language theory. About 465BC Hippasus writes of a "sphere of 12 pentagons", which must refer to a dodecahedron About 450BC Greeks begin to use written numerals. (See this History Topic About 450BC Zeno of Elea presents his paradoxes. About 440BC Hippocrates of Chios writes the Elements which is the first compilation of the elements of geometry. About 430BC Hippias of Elis invents the quadratrix which may have been used by him for trisecting an angle and squaring the circle About 425BC Theodorus of Cyrene shows that certain square roots are irrational . This had been shown earlier but it is not known by whom. About 400BC Babylonians use a symbol to indicate an empty place in their numbers recorded in cuneiform writing. There is no indication that this was in any way thought of as a number. (See this History Topic Plato founds his Academy in Athens About 375BC Archytas of Tarentum develops mechanics. He studies the "classical problem" of

8. Archimedes And The Computation Of Pi A page that contains links information on Archimedes and an interactive applet that illustrates how Category Science Math Recreations Specific Numbers Pi...... Here are some links to other Archimedes related web pages eratosthenes of cyrenewas a contemporary of Archimedes (Eratosthenes was about ten years younger http://www.math.utah.edu/~alfeld/Archimedes/Archimedes.html

Peter Alfeld, Department of Mathematics, College of Science University of Utah Archimedes and the Computation of Pi Archimedes (approximately 285-212 B.C.) was the most famous ancient Greek mathematician and inventor. He invented the Screw of Archimedes , a device to lift water, and played a major role in the defense of Syracuse against a Roman Siege, inventing many war machines that were so effective that they long delayed the final sacking of the city. For a concise and yet informative discussion of Archimedes see the article "Archimedes" in the macropedia of the Encyclopedia Britannica. Here are some links to other Archimedes related web pages: Eratosthenes of Cyrene was a contemporary of Archimedes (Eratosthenes was about ten years younger), and the two corresponded on various matters. A listing of Pi to 10,000 digits,

9. Eratosthenes Of Cyrene (ca. 284-ca. 192 BC) -- From Eric Weisstein's World Of Sc eratosthenes of cyrene (ca. 284ca. 192 BC), Consummate Greek scholarwhose status as second best in each field earned him the nickname http://scienceworld.wolfram.com/biography/Eratosthenes.html

Branch of Science Astronomers Branch of Science Geographers ... Greek Eratosthenes of Cyrene (ca. 284-ca. 192 BC) Consummate Greek scholar whose status as second best in each field earned him the nickname "Beta." He served as librarian at the great library in Alexandria, and wrote works of mathematics, geography, philosophy, and astronomy. He also wrote a poem called Hermes which described the fundamentals of astronomy in verse! Although most of Eratosthenes' writings are lost, many are preserved through the writings of commentators. Among Eratosthenes' accomplishments was the accurate measurement the diameter of the Earth by observing that, on the day of the summer solstice the Sun zenith in Alexandria, which he assumed was due north of Syene (Dunham 1990). Unfortunately, since the original work On the Measurement of the Earth was lost, the details of Eratosthenes' procedure are not known. Eratosthenes also determined the obliquity of the ecliptic prepared a star map containing 675 stars suggested that a leap day be added every fourth year, tried to construct an accurately-dated history, and developed the " sieve of Eratosthenes " method of finding

10. ERATOSTHENES - Who Was Eratosthenes Of Cyrene? eratosthenes of cyrene (276194 BC) Eratosthenes was born in Cyrenewhich is now in Libya. After studying in Alexandria and Athens http://www.eranet.gr/eratosthenes/html/eoc.html

Eratosthenes of Cyrene (276-194 BC) Eratosthenes was born in Cyrene which is now in Libya. After studying in Alexandria and Athens, he became the director of the Great Library in Alexandria. It was there where he read about a deep vertical well near Syene (now Aswan) in southern Egypt, which, once a year at noon (on the day of the Summer Solstice), was entirely lit up to the bottom by the sun, that is, the sun was directly overhead, with its rays shining directly into it. He then placed a vertical post at Alexandria (which was almost due north of Syenne) and measured the angle of its shadow on that exact date and time. Making the assumptions that (a) the earth is round and that (b) the sun's rays are essentially parallel, Eratosthenes knew from geometry that the size of the measured angle equaled the size of the angle at the earth's center between Syene and Alexandria. Knowing also that the arc of an angle this size was 1/50 of a circle, and that the distance between Syene and Alexandria was 5000 stadia, he multiplied 5000 by 50 to find the earth's circumference. His result, 250,000 stadia (about 46,250 km), is quite close to modern measurements.

11. ERATOSTHENES - The Company To constantly follow technological developments which enhance our knowhowand productivity. Learn Who was eratosthenes of cyrene? http://www.eranet.gr/eratosthenes/html/aboutus.html

ERATOSTHENES has been operating since the mid 70’s and has become one the of the largest and most specialized consultancies in Greece, offering services to the public and private sectors, and the EU, in the fields of engineering, planning, GIS applications and applied research. ERATOSTHENES is organized in the following departments: Cadastre Department G.I.S. Departmant Transport Studies Department Digital Data Department Quality Management Department Administrative Department Our Aims: To satisfy our clients’ requirements with emphasis on high quality and speedy delivery To develop new advanced methods and techniques for the organisation, management and execution of our projects To constantly follow technological developments which enhance our know-how and productivity Learn: Who was Eratosthenes of Cyrene? [the Company] [ Services Products Software Research ... Contacts Created by EraNET F_menu(new Array('NavigationBar21', '../html/cadastre.html','../assets/images/autogen/Cadastre_NButtonP1.gif','../assets/images/autogen/Cadastre_NRButtonP1.gif','../html/gis.html','../assets/images/autogen/G.I.S._NButtonP1.gif','../assets/images/autogen/G.I.S._NRButtonP1.gif','../html/tsd.html','../assets/images/autogen/Transport_St._NButtonP1.gif','../assets/images/autogen/Transport_St._NRButtonP1.gif','../html/data.html','../assets/images/autogen/Digital_Data_NButtonP1.gif','../assets/images/autogen/Digital_Data_NRButtonP1.gif'));

12. TMTh:: ERATOSTHENES OF CYRENE ASTRONOMER, GEOGRAPHER eratosthenes of cyrene (fl. 276 194 BC) LifeOne of the greatest of the ancient Greek sages and the first http://www.tmth.edu.gr/en/aet/2/43.html

Home Ancient Greek Scientists AGRICULTURALISTS ARCHITECTS ... PHYSICISTS ASTRONOMER, GEOGRAPHER ERATOSTHENES OF CYRENE (fl. 276 - 194 BC) Life One of the greatest of the ancient Greek sages and the first great geographer of the ancient world, Eratosthenes is considered the founder of physical and mathematical geography. He studied in Athens with Ariston of Chios and Archesilaus, then moved to Alexandria, where he spent most of the rest of his life. Ptolemy III Euergetes appointed him director of the famous Library of Alexandria. It was Eratosothenes who coined the term "philologist". Archimedes, his senior by 11 years, held him in very high esteem, and dedicated two of his works to him: "On the Method of Mechanical Theorems" and "The Cattle Problem". He is cited by Stobaeus. One of the moon's craters has been named "Eratosthenes" in his honour. Work His principal works are: "Proof of the sphericity of the earth": In this work Eratosthenes employed a method still used in modern astronomy, which was based on four assumptions: A) At Syene (now Aswan, in Upper Egypt), which is in the Tropic of Cancer, the sun's rays fall vertically at noon at the summer solstice.

13. TMTh:: Ancient Greek Technologists OF SOLI ARISTARCHUS OF SAMOS ARISTOTLE OF STAGIRA AUTOLYCUS OF PITANE CALLIPPUSOF CYZICUS DEMOCRITUS EPICURUS OF SAMOS eratosthenes of cyrene EUDEMUS OF http://www.tmth.edu.gr/en/aet/2.html

Home Ancient Greek Scientists AGRICULTURALISTS ARCHITECTS ARTISTS ASTRONOMERS ... XENOCRATES OF CHALCEDON Read about the life and Work of Ancient Greek Scientists. Choose the desired category from the list on the left and the desired scientist from the list on the right Based on the Greek book: K. Georgakopoulos, "Ancient Greek Scientists", Athens, 1995 Contact the Technology Museum

14. - Great Books - Eratosthenes (c. 276 BCc. 196 BC), Brief Biography Eratosthenes was born in Cyrenewhich is now in Libya in North Africa. Best Choice. eratosthenes of cyrene. http://www.malaspina.com/site/person_515.asp

Eratosthenes (c. 276 BC-c. 196 BC) Brief Biography Eratosthenes was born in Cyrene which is now in Libya in North Africa. His teachers included the scholar Lysanias of Cyrene and the philosopher Ariston of Chios who had studied under Zeno, the founder of the Stoic school of philosophy. Eratosthenes also studied under the poet and scholar Callimachus who had also been born in Cyrene. Eratosthenes then spent some years studying in Athens. Eratosthenes made a surprisingly accurate measurement of the circumference of the Earth. Details were given in his treatise On the measurement of the Earth which is now lost. However, some details of these calculations appear in works by other authors such as Cleomedes, Theon of Smyrna and Strabo . Eratosthenes compared the noon shadow at midsummer between Syene (now Aswan on the Nile in Egypt) and Alexandria. He assumed that the sun was so far away that its rays were essentially parallel, and then with a knowledge of the distance between Syene and Alexandria, he gave the length of the circumference of the Earth as 250,000 stadia. [Adapted from MacTutor Detailed Biography Eratosthenes was the second librarian of the Great Library of Alexandria, so called to distinguish it from the smaller or "daughter" library in the Serapeum, was a foundation of the first Ptolemies for the purpose of aiding the maintenance of Greek civilization in the midst of the conservative Egyptians. If the removal of Demetrius Phalereus to Alexandria, in 296-295 B.C., was connected with the organization of the library, at least the plan for this institution must have been formed under Ptolemaios Soter (died c. 284 B.C.), but the completion of the work and its connection with the Museum was achievement of his successor, Ptolemaios Philadelphos. As

15. Eratosthenes Of Cyrene eratosthenes of cyrene. Born 276 BC in Cyrene (nowShahhat, Libya) Died 197 BC in Alexandria, Egypt. http://www.hsu.edu/faculty/worthf/mathematicians/Eratosthenes/tsld001.htm

Eratosthenes of Cyrene Born: 276 BC in Cyrene (now Shahhat, Libya)Died: 197 BC in Alexandria, Egypt Next slide Back to first slide View graphic version

16. Malaspina.com - Eratosthenes Of Cyrene (ca. 276-ca. 196 BC) Click here for rare books! Launch Previous Entry in New Window Malaspina ScienceDatabase Launch Next Entry in New Window eratosthenes of cyrene (ca. 276ca. http://www.mala.bc.ca/~mcneil/eratos1.htm

Eratosthenes of Cyrene (ca. 276-ca. 196 BC) [MacTutor] Great Books Biography [Malaspina] Amazon Search Form] Library of Congress Online Citations [LC] Library of Congress Offline Citations [MGB] COPAC UK Online Citations [COPAC] Free Online Practice Exams [Grad Links] Canadian Book Orders! Chapters-Indigo Save on Textbooks! [Study Abroad] Used Books Search Form Alibris Dummies Books Amazon Books from Amazon Amazon EBay! Ebay Books from Amazon UK Amazon UK Books from Chapters Canada [Orders through Chapters The librarian who measured the earth Amazon Eratosthenes of Cyrene Amazon The Sieve of Eratosthenes [MacTutor, St. Andrews] Additional Biography [University of Virginia] More on the sieve of Eratosthenes [Jim Carlson] Map of the World according the Eratosthenes of Cyrene Top of Page

17. Eratosthenes Of Cyrene (c.276-c.196 BC) Library Of Congress Rare and Hardto-Find Books from Alibris eratosthenes of cyrene (c.276-c.196BC) Library of Congress Citations The Little Search Engine that Could. http://www.mala.bc.ca/~mcneil/cit/citlceratosthenes.htm

Eratosthenes of Cyrene (c.276-c.196 BC) : Library of Congress Citations The Little Search Engine that Could Down to Name Citations LC Online Catalog Amazon Search ... Free Email from Malaspina Book Citations [16 Records] Author: Fraser, P. M. (Peter Marshall) Title: Eratosthenes of Cyrene, by P. M. Fraser. Published: London, Oxford University Press, 1971. Description: 35 p. 25 cm. Series: Lecture on a master mind, British Academy, 1970 Proceedings of the British Academy, v. 56 LC Call No.: AS122 .L5 vol. 56 G87.E73 Dewey No.: 082 s 520/.92/4 B ISBN: 0197256619 Notes: Includes bibliographical references. Subjects: Eratosthenes. Series Entry: Annual lecture on a master mind ; 1970. Control No.: 72183166 //r852 Author: Kapseomenos, Eratosthenees G. Title: To synchrono kreetiko historiko tragoudee : hee domee kai hee ideologia tou / Eratosthenees G. Kapseomenos. Published: Atheena : Themelio, c1979. Description: 284 p. ; 21 cm. LC Call No.: PA5639.C7 K37 1979 Notes: Bibliography: p. [273]-[279] Includes index. Subjects: Folk songs, Greek (Modern) Greece Crete History and criticism. Political ballads and songs Greece Crete History and criticism. Protest songs Greece Crete History and criticism. Control No.: 80109976 //r91

18. Eratosthenes Hub eratosthenes of cyrene by the University of Utah the interactive applet on thispage illustrates the Sieve of Eratosthenes. eratosthenes of cyrene (ca. http://www.knowdeep.org/eratosthenes/

Eratosthenes was born in Cyrene, North Africa (now Shahhat, Libya) in 276 BC. He was a mathematician, astronomer, historian and geographer. Eratosthenes measured the circumference of the earth with an error of about 10%. Sieve of Eratosthenes - definition of Sieve of Eratosthenes, possibly with links to more information and implementations. Eratosthenes of Cyrene by the University of Utah - the interactive applet on this page illustrates the Sieve of Eratosthenes. Eratosthenes Measures Earth's Circumference - by Dennis P. Donovan , Rice University. Eratosthenes's measurement of the size of the earth - from St. Ambrose University, Astronomy and Earth Science. Eratosthenes and the Size of the Earth - from Bucknell University Physics Department. The Sieve of Eratosthenes - Kevin Coombes, Department of Mathematics, University of Maryland. Eratosthenes of Cyrene - from School of Mathematics and Statistics University of St Andrews, Scotland. Eratosthenes 276-195 B.C.E. Eratosthenes of Cyrene - from Mr. C's Math Classroom, West Valley Junior High. Eratosthenes of Cyrene 270 - 190 BC - by BBC Education.

19. Eratosthenes Of Cyrene (c.276-c.194 B.C.) A B C D E F G H I J K L M N O P Q R S T U V W X Y Z eratosthenes of cyrene (c.276c.194 BC) http://www.angelfire.com/on2/daviddarling/Eratosthenes.htm

The Encyclopedia of Astrobiology, Astronomy, and Spaceflight about main latest news news archive ... Z Eratosthenes of Cyrene (c.276-c.194 B.C.) Greek astronomer and mathematician who made the first reasonably accurate calculation of the Earth's circumference, obtaining a value of about 46,000 kilometers. See ancient philosophy, related to the possibility of extraterrestrial life var site="s13space1234"

20. Astro A-Z: E theory energybased life enzymes Epicurus epidemics, from space Epimetheus epistellarjovians Epsilon Eridani eratosthenes of cyrene EROS (Experience pour la http://www.angelfire.com/on2/daviddarling/alphindexe.htm

The Encyclopedia of Astrobiology, Astronomy, and Spaceflight encyclopedia main latest news news archive ... var site="s13space1234"

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Page 1     1-20 of 88    1  | 2  | 3  | 4  | 5  | Next 20