Report: How Greeks knew the Earth was round 25 centuries ago

Α Decrease font Enlarge font
Report: How Greeks knew the Earth was round 25 centuries agoAncient Greek Mathematician, Eratosthenes 2200 years ago calculated precisely the circumference of our entire globe with just a stick and his brain

It wasn’t until the mid-20th century that humans managed to launch satellites into space and determine the exact kilometers of the circumference of the Earth: 40,030 kilometers.

But how could an Ancient Greek Mathematician, Eratosthenes, manage to find almost the exact same number, without having any pictures of Earth from the space or even proper measuring tools? Eratosthenes didn’t have much more than…a stick and his brain.

More than two thousand years ago, Eratosthenes heard that in Syene, a city south of Egypt’s Alexandria, no vertical shadows were cast at noon on the summer solstice as the sun was directly overhead. So, the Greek Mathematician wondered if this was the case in Alexandria too, a few hundreds of miles to the North of Syene.

So, he decided to carry out an experiment. On June 21, he went to Alexandria and he put a stick directly in the ground and waited to see if a shadow would be cast at noon. It turns out there was one and he tried to measure it. The shadow casted was about 7 degrees.

Eratosthenes’ calculations

Now, Eratosthenes drew a very logical conclusion: If the sun’s rays are coming in at the same angle at the same time of day, and a stick in Alexandria is casting a shadow of 7 degrees while the stick in Syene is not casting a shadow at all, it means that the Earth’s surface is curved.

The notion of a spherical Earth was already known by Pythagoras around 500 BC and validated by Aristotle a few centuries later. So if the Ancient Greeks before him were right and the Earth was a sphere, Eratosthenes could use his observations to calculate the circumference of our planet.

After hiring a man to pace the distance between Syene and Alexandria, he discovered that the two cities were 5,000 stadia apart, which is about 800 km.

He could then use simple proportions to measure the Earth’s circumference — 7.2 degrees is 1/50 of 360 degrees, so 800 times 50 equals 40,000 kilometers.

And just like that, an Ancient Greek 2200 years ago calculated precisely the circumference of our entire globe with just a stick and his brain.

Read more at greekreporter.com

RELATED TOPICS: GreeceGreek tourism newsTourism in GreeceGreek islandsHotels in GreeceTravel to GreeceGreek destinations Greek travel marketGreek tourism statisticsGreek tourism report

Photo Source: Wikimedia Commons Copyright: Reto Stöckli License: CC-BY-SA 

 

Tornos
  1. 13/11 01:55

    First Greek supermarket opens in Germany

  2. 13/11 01:51

    5786 Turks have sought asylum in Greece following the failed coup in 2017

  3. 13/11 01:46

    Greek exports to surpass 33 billion euros by end of 2018

  4. 13/11 01:41

    Bank of Greece points to higher residential property prices in Q3 2018

  5. 13/11 01:29

    International Conference on Marine Mammal Protected Areas held in Greece

  6. 13/11 01:20

    Culture Tourism: The Platonic Academy of Athens, the world’s first university

  7. 13/11 01:13

    Campaign to save Hellenique Fondation "Greek House" in Paris

  8. 13/11 01:05

    Lemnos Gallipoli Committee commemorates Armistice Day 1918 on Mudros Bay

  9. 12/11 23:55

    Antique musical instruments at Ancient Nikopolis Museum in Greece

  10. 12/11 21:50

    The superb health benefits of Greek honey

  11. 12/11 21:43

    Vote for the Greek island of Corfu in EUFCN Location Award competition

  12. 12/11 19:25

    Nike honors of Greek Olympic legend Louis with new Air Zoom Spiridon

  13. 12/11 16:20

    UAE investment firm Mubadala invites Greek firms for cooperation

  14. 12/11 15:06

    Sports Tourism: Greek girl wins karate world championship (video)

  15. 12/11 13:01

    China expresses strong interest in Greek products and services

  16. 12/11 11:55

    EBRD-funded programs for Greek small and medium-sized enterprises

  17. 11/11 20:58

    Voice of Greece renewed program beginning on Monday, November 12th

  18. 11/11 20:46

    Brimin Kipkorir Misoi from Kenya wins 36th Authentic Athens Marathon (video)

  19. 11/11 20:29

    Educational programs for kids at the Museum of Cycladic Art in Athens

  20. 11/11 18:53

    APRA welcomes European Court of Auditors’ special report on passengers’ rights

  21. 11/11 16:42

    Direct metro connection to Athens airport resumes operations on Saturday

  22. 11/11 12:35

    UNWTO: Outbound tourism spending from the Gulf 6 times the global average

  23. 11/11 10:11

    Russian archaeologists unearthed ancient Greek settlement in Crimea peninsula

  24. 10/11 14:08

    Saffron 'the red gold of the Greek land' to reach Chinese shops by 2019

  25. 10/11 13:59

    Greek industrial output grows by 2% year-on-year in September

  26. 10/11 13:55

    Cyprus building permits significantly grow between January – August 2018

  27. 10/11 13:47

    Photo of flight attendant breastfeeding passenger’s baby goes viral

  28. 10/11 13:35

    Education Tourism: First school reader in demotic Greek turns 100

  29. 10/11 13:22

    Medical Tourism: Onassis Foundation head notes new era for transplants in Greece

  30. 10/11 12:31

    IMF more optimistic on Greek economy that European Union

  31. 10/11 11:16

    The Times 2018 spotlight on Cyprus: Opportunity knocks for investors...

  32. 09/11 21:23

    Religious Tourism: How Arkadi became symbol of self sacrifice for freedom

  33. 09/11 21:23

    NGTO and Aegean launch new campaign to promote Athens and Thessaloniki

  34. 09/11 21:07

    Power supply restored on the Greek island of Rhodes

  35. 09/11 19:53

    History Tourism: Phryne, the Ancient Greek model who stripped for her freedom

  36. 09/11 19:36

    Interconnector Greece-Bulgaria gets nod of the European Commission

  37. 09/11 19:19

    Russian tycoon Rybolovlev released but remains still under investigation

  38. 09/11 19:10

    Archaeological Museum on Greek island of Corfu to reopen after six years

  39. 09/11 18:43

    Greece extends Golden Visas for affluent foreign investors

  40. 09/11 16:41

    New Victoria Hislop book inspired by the Greek island of Makronisos

  41. 09/11 14:58

    16 Greek enterprises participate in business mission to Nigeria

  42. 09/11 14:47

    Record 415 exhibitors in Philoxenia and another 200 in Hotelia

  43. 09/11 12:49

    Greek Cultural Day marks Greek migration in Sydney of Australia

  44. 09/11 12:42

    Evgenios Vassilikos: November established as Month of Marathon for Athens tourism

  45. 09/11 11:39

    Greek tennis star Tsitsipas Most Improved Player of 2018 at ATP awards

  46. 08/11 20:04

    Hadjigeorgakis house and Hala Sultan Mosque closed on 10 and 20 November

  47. 08/11 19:49

    Religious Tourism: Monastery of Archangel Michael in Panormitis on Symi island

  48. 08/11 19:41

    EU Commission report: Greek economy to grow by 2% in next three years

  49. 08/11 19:30

    Iconic Comedie-Francaise to perform in ancient Greek theater of Epidaurus

  50. 08/11 19:11

    “Reviving” of Mycenaean acropolis of Gla in Viotia area of Central Greece

  51. 08/11 19:09

    Trastor REIC buys real estate asset in Halandri suburb of Attica for 4 million

  52. 08/11 18:52

    Greek Tourism: 58% of overnight stays in Greece are from EU countries

  53. 08/11 18:43

    “BlueGrowth Piraeus” innovation contest to take place on December 3

  54. 08/11 17:59

    European Union: Greece attains top rates in sea water quality

  55. 08/11 17:10

    School in Greek island of Antikythera opens with 3 students

  56. 08/11 17:07

    Travel data: Most Russian tourists focus on Athens and Attica coast

  57. 08/11 15:14

    Greek unemployment drops to 18.9% lowest levels since August 2011

  58. 08/11 13:04

    Russian ambassador shows interest in new natgas pipeline being extended to Greece

  59. 08/11 11:49

    Report: 10 important things that Canada and Greece have in common

  60. 08/11 01:07

    Greek wineries open to visitors on Sunday for European Day of Wine Tourism

  61. 08/11 00:59

    Greek public sector federation ADEDY calls strike on November 14

  62. 08/11 00:19

    More than 15,000 foreign runners in Athens for The Original Marathon

  63. 08/11 00:11

    Santorini cruise company wins "Best in Luxury" award at WTM 2018

  64. 07/11 23:49

    Greek Tourism Minister at WTM: New record with 33 million arrivals and €2 billion higher revenues in 2018

  65. 07/11 23:44

    Traffic restrictions for Athens Authentic Marathon 2018 on Sunday 11 November

  66. 07/11 23:19

    WTM 2018 | Quality tourism ideal antidote to overtourism for European destinations

  67. 07/11 23:09

    Ancient Greek workshops for aspiring archaeologists by Greek Embassy in US

  68. 07/11 22:57

    Greek wine production drops in 2018

  69. 07/11 22:51

    First locally managed hydroelectric plant inaugurated in North Western Greece

  70. 07/11 22:44

    Christmas Ballet Gala at Olympic Hall in Athens between November 24-25

  71. 07/11 21:40

    Photo of Greek groom giving bride yellow card becomes viral (video)

  72. 07/11 21:39

    Greek-American genealogical experts join forces to support Greece’s archives

  73. 07/11 21:37

    National Library in Athens to launch trial version of e-Reading Room

  74. 07/11 21:25

    Swan Lake at Athens National Opera between November 10 - December 29

  75. 07/11 21:19

    Vote for the Greek tourism video at this year’s CIFFT People’s Choice Award

  76. 07/11 21:10

    Greek Film Days in Prague on 100th anniversary of Czech Independence

  77. 07/11 19:57

    Experiental travel report: Greece’s most authentic villages

  78. 07/11 18:54

    Irish stand-up comedy in Monastiraki, Athens on November 29

  79. 07/11 17:40

    The history of tourism in Cyprus presented in video at WTM 2018

  80. 07/11 16:47

    Leros and ‘Greek Challenge’ bid to host the Extreme Sailing Series

  81. 07/11 15:32

    Rival Consoles concerts at Athens St Paul’s Anglican Church on November 8-9

  82. 07/11 15:23

    Cyprus Tourism Minister content with 2018 performance and WTM meetings

  83. 07/11 14:10

    Axion Hellas renovates small outpost in eastern Aegean island of Psara

  84. 07/11 12:01

    Three "green" initiatives along the authentic Athens Marathon 2018

  85. 07/11 11:53

    Cypriot air traffic controllers warn about danger due to staff shortage

  86. 07/11 10:37

    Marathon tribute at Athens National Archaeological Museum till November 15

  87. 07/11 02:10

    DER Touristik: 2019 will be Greece's year

  88. 07/11 02:05

    Nia Vardalos, John Stamos and THI raise funds for orphanage burnt by Attica fires

  89. 07/11 01:30

    Airlander 10: World’s biggest aircraft takes to the air again

  90. 07/11 01:20

    Folk Tourism: Maria Pentagiotissa, a female legend in Greece (videos)

  91. 07/11 01:09

    Religious Tourism: Visiting Greece’s magical monasteries of Meteora

  92. 07/11 01:02

    Media: Anti-ride sharing Greek taxi drivers to strike on November 8

  93. 07/11 00:54

    Greek Land Registry: 170K properties of 'unknown owner' will revert to the State

  94. 06/11 23:52

    Historic villa of legendary Greek Admiral Miaoulis on Hydra up for sale

  95. 06/11 23:04

    Minister at World Travel Market: Cyprus touching 4 million visitors in 2018

  96. 06/11 23:00

    Sports Tourism: Authentic Athens Marathon is like no other on Earth

  97. 06/11 22:42

    Greek Golden Visas magnetize more wealthy property buyers from abroad

  98. 06/11 22:25

    Business travelers from 30 countries at 3rd Fur Shopping Festival in Greece

  99. 06/11 21:57

    Athens wins European Capital of Innovation prize for 2018 (video)

  100. 06/11 20:08

    Five major commercial aviation companies are based and operate in Greece