Eratosthenes, a Greek mathematician and astronomer (276 BC), measured of Earth’s circumference by using the shadow angles from the sun in two locations. He calculated it was 39,375 km, which is 1.4% less than the real number of 40,076 km

Eratosthenes

This article is about the Greek scholar of the third century BC. For the crater named after him, see Eratosthenes (crater). For the ancient Athenian statesman of the fifth century BC, see Eratosthenes (statesman).

Eratosthenes of Cyrene (/ɛrəˈtɒsθəniːz/; Greek: Ἐρατοσθένης ὁ Κυρηναῖος, romanized: Eratosthénēs ho Kurēnaĩos, IPA: [eratostʰénɛːs]; c. 276 BC[note 1] – c. 195/194 BC)[note 2] was a Greek polymath: a mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria. His work is comparable to what is now known as the study of geography, and he introduced some of the terminology still used today.

He is best known for being the first person to … Continue Reading (11 minute read)

15 thoughts on “Eratosthenes, a Greek mathematician and astronomer (276 BC), measured of Earth’s circumference by using the shadow angles from the sun in two locations. He calculated it was 39,375 km, which is 1.4% less than the real number of 40,076 km”

  1. Kontiyak

    Imagine what this guy’s reaction would be if he was shown a picture of a person 2300 years in the future holding a banner “Earth is flat”

  2. obersttseu

    Was the error due to the fact that earth isn’t a perfect sphere?

  3. Game_of_Jobrones

    His nickname was “Beta” because his contemporaries said he was second-best in every field of philosophy.

    Well we’re talking about him now on the Internet millennia later. Who’s the beta now motherfuckers?

  4. danarsky

    …thus, scientists knew the Earth was spherical 1,600 years before Columbus sailed and they knew that there was a whole lot more of the globe to explore between India and the West Indies.

  5. MightyDoomSlayer

    And yes, a guy with 2 sticks and math knowledge can prove earth isn’t flat, imagine what can someone with 2 sticks, a car and a pocket computers can achieve… Exactly, FaceBook rants about sticks

  6. lastaccountgotlocked

    “What the hell is a kilometre, Eratosthenes?!”

  7. Thedrunner2

    He was known to head butt his detractors.

  8. supremedalek925

    What I never understood about this experiment is how did he measure two shadows in two different locations at the same time?

  9. DeathLeopard

    It was supposed to be exactly 40,000 km. That was the original definition of the meter but they were a bit off when they made that measurement too.

  10. LittleYellowScissors

    What if his measurements where accurate and the Earth has grown 1.4% since then

  11. TavrosNitrous

    Earth got fatter in the 2300 years afterwards

  12. freshremake

    How many bald eagles is that?

  13. YankeeMinstrel

    I remember reading somewhere that if you take into account the lack of standardized measurement across the ancient world, one of the local units of length he might have been using would put it at an even more accurate number.

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