See soorce fer Eratosthenes

{{Infobox person
| name = Eratosthenes
| image = Eratosthene.01.png
| alt = An etchin o a man's heid an neck in profile, leuking tae the richt. The man haes a beard an is baldin.
| birth_date = 276 BC
| birth_place = [[Cyrene, Libie|Cyrene]]
| death_date = 194 BC
| death_place = [[Alexandria]]
| ethnicity = Greek
| occupation = {{hlist|class=nowrap |Scholar |Librarian |Poet |Inventor}}
}}
'''Eratosthenes o [[Cyrene, Libie|Cyrene]]''' ({{IPAc-en|ɛr|ə|ˈ|t|ɒ|s|θ|ə|n|iː|z}}; {{lang-grc-gre|Ἐρατοσθένης}}, {{IPA-el|eratostʰénɛːs|IPA}}; {{nowrap|c. 276 BC}}<ref>The [[Suda]] states that he wis born in the 126t [[Olympiad]], (276–272&nbsp;BC). [[Strabo]] (''Geography'', i.2.2), tho, states that he wis a "pupil" (γνωριμος) o [[Zeno o Citium]] (who died 262&nbsp;BC), that wad implee an earlier year-o-birth ({{nowrap|c. 285 BC}}) syne he is unlikely tae hae studied unner him at the young age o 14. However, γνωριμος can an aa mean "acquaintance", an the year o Zeno's daith is bi no means definite. Cf. ''Eratosthenes'' entry in the ''[[Dictionary of Scientific Biography]]'' (1971)</ref>&nbsp;– {{nowrap|c. 195/194 BC}}<ref>The [[Suda]] states he died at the age o 80, [[Censorinus]] (''De die natali'', 15) at the age o 81, an [[Pseudo-Lucian]] (''Makrobioi'', 27) at the age o 82.</ref>) wis a [[Greek mathematics|Greek mathematician]], [[geografer]], [[poet]], [[astronomer]], an [[muisic theory|muisic theorist]]. He wis a man o learin, acomin the chief leebrarian at the [[Leebrar o Alexandria]]. He inventit the discipline o [[geografie]], includin the terminology uised the day.<ref name="Roller, Duane W 2010">Roller, Duane W. Eratosthenes' Geography. New Jersey: Princeton University Press, 2010.</ref>

He is best kent for bein the first person tae calculate the [[History o geodesy#Hellenic warld|circumference o the Yird]], that he did bi comparin [[Angle o incidence (optics)|angles]] o the mid-day Sun at twa places a kent North-Sooth distance apairt.<ref>{{cite book|title=The Illustrated Encyclopedia of the Universe|last=Ridpath|first=Ian|publisher=Watson-Guptill|year=2001|isbn=0-8230-2512-8|location=New York, NY|page=31}}</ref> His calculation wis remerkably accurat. He wis an aw the first tae calculate the [[Axial tilt#Obliquity o the ecliptic (Yird's axial tilt)|tilt o the Yird's axis]], again wi remerkable accuracy.<ref>[http://hosting.astro.cornell.edu/academics/courses/astro201/eratosthenes.htm "Eratosthenes (276 - 195 B.C.)"] {{Webarchive|url=https://web.archive.org/web/20210224112430/http://hosting.astro.cornell.edu/academics/courses/astro201/eratosthenes.htm |date=2021-02-24 }}. Cornell University. Accessed 28 Julie 2019.</ref> Additionally, he mey hae accuratly calculatit the [[Astronomical unit|distance frae the Yird tae the Sun]] an inventit the [[leap day]].<ref>{{cite journal|url=https://www.wired.com/science/discoveries/news/2008/06/dayintech_0619 |title=June 19, 240 B.C.: The Earth Is Round, and It's This Big |first=Randy |last=Alfred |journal=Wired |date=June 19, 2008 | accessdate=2013-06-22}}</ref> He creatit the first [[Auncient warld maps#Eratosthenes (276–194 BCE)|map o the warld]], incorporatin [[Circle o latitude|parallels]] an [[Longitude|meridians]] based on the available geografic knawledge o his era.

Eratosthenes wis the foonder o scienteefic [[chronology]]; he endeavoured tae revise the dates o the chief leeterar an poleetical events frae the conquest o [[Troy]]. Eratosthenes datit [[Trojan War|The Sack o Troy]] tae 1183 BC. In [[nummer theory]], he introduced the [[sieve o Eratosthenes]], an efficient method o identifeein [[prime nummer]]s.

He wis a feegur o influence in mony fields.  Accordin tae an entry<ref>Entry {{lang|grc|ε}} 2898</ref> in the [[Suda]] (a 10t-century reference), his creetics scorned him, cryin him ''Beta'' (the seicont letter o the Greek alphabet) acause he ayeweys cam in seicont in aw his endeavors.<ref>See also Asimov, Isaac. ''Asimov's Biographical Encyclopedia of Science and Technology'', new revised edition. 1975. Entry #42, "Eratosthenes", Page 29. Pan Books Ltd, London. {{ISBN|0-330-24323-3}}. This was also asserted by Carl Sagan 31 minutes into his Cosmos episode ''The Shores of the Cosmic Ocean''</ref> Nanetheless, his devotees nicknamed him ''Pentathlos'' efter the Olympians that war weel roondit competitors, for he haed pruiven himsel tae be knawledgeable in ivery aurie o learin. Eratosthenes yearned tae unnerstaund the complexities o the entire warld.<ref name="Chambers, James T 1998">Chambers, James T. "Eratosthenes of Cyrene." Dictionary Of World Biography: The Ancient World (January 1998): 1–3.</ref>

==References==
{{Reflist}}

[[Category:276 BC]]
[[Category:194 BC]]
[[Category:3rd-century BC Greek fowk]]
[[Category:3rd-century BC poets]]
[[Category:Auncient Greek astronomers]]
[[Category:Auncient Greek geografers]]
[[Category:Auncient Greek muisic theorists]]
[[Category:Auncient Greek mathematicians]]
[[Category:Auncient Greek poets]]
[[Category:Cyrenean Greeks]]
[[Category:Daiths bi stairvation]]
[[Category:Geodesists]]
[[Category:Geometers]]
[[Category:Hellenistic Egyptians]]
[[Category:Leebrarians o Alexandria]]
[[Category:Nummer theorists]]
[[Category:270s BC births]]
[[Category:190s BC daiths]]