On This Day: Eratosthenes Calculated the Earth’s Circumference in Ancient Greece

·

Ancient Greeks made some of the most impressive astronomical discoveries in history, including when Eratosthenes calculated the circumference of the Earth.

It wasn’t until the mid-20th century that we managed to launch satellites into space and determine the exact kilometers of the circumference of the Earth: 40,030.2 kilometers.

But how, then, could the ancient Greek mathematician, Eratosthenes, manage to find pretty much the exact same number, without having any pictures of Earth from space or even proper measuring tools?

Born in Cyrene, an ancient Greek colony in modern-day Libya, in 276 BC, Eratosthenes was a polymath–meaning that he had vast knowledge of many different subjects, including mathematics, astronomy, music theory, and poetry.

Over two thousand years ago, Eratosthenes heard that in Syene, a town south of Alexandria in Egypt, no vertical shadows were cast at noon on the summer solstice as the sun was directly overhead.

He decided to conduct an experiment. On June 19, he went to Alexandria and 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 cast measured to about seven degrees.

Eratosthenes accomplished many feats throughout his life, including the creation of a chronology of Greek history, an algorithm to find every prime number, and the first global projection of the Earth.

Advertisement

Share:

KEEP UP TO DATE WITH TGH

By subscribing you accept our Terms of Service and Privacy Policy.

Advertisement

Latest News

Webinar for Greeks abroad tackles key tax issues and draws hundreds

The first TaxWebinar dedicated exclusively to Greeks abroad and tax residents of other countries was held on Wednesday, July 9.

From passports to tax reform: Loverdos sets agenda ahead of Australia visit

Loverdos has confirmed that he will be visiting Australia from 8 to 26 October, acknowledging the government’s absence from the country.

‘I’m not done yet’: Ange Postecoglou reflects on heritage and coaching dreams

Ange Postecoglou sat down with The Greek Herald to reflect on his philosophy and his cultural heritage. Read the interview here.

Heritage NSW inspects Paragon Café as emergency works get underway

The Paragon Café in Katoomba has taken its first meaningful steps toward preservation following a recent on-site inspection by Heritage NSW.

Māori-Greek artist’s tribute to ancestors lights up Manhattan billboard

Māori-Greek artist Jimmy James Kouratoras has made a striking return to New York, with his painting Hei Tiki – For the Love of Our Ancestors.

You May Also Like

Michael Pavlou recalls ‘panic’ during machete brawl at Melbourne shopping centre

Melbourne father Michael Pavlou described scenes of “panic” and “confusion” during a violent incident at Northland Shopping Centre on Sunday.

SYRIZA demands response for Erdogan’s ‘unconscionable’ Cyprus claims  

Greece’s main opposition party on Tuesday condemned recent comments made by Turkey's President, Recep Tayyip Erdogan concerning Cyprus.

Archontia Mantzaridou, Kyriaki Melliou aim to preserve migrant stories of Kytherians in Australia

Suitcases loaded with dreams and nostalgia, while the Greek diaspora landed on the shores of Australia in the 1950s and 60s