Eratosthenes actually had it easy, he already knew of a nearby city (Syene) where the sun was directly overhead at midday on one day of the year - the summer solstice - meaning that all he had to ...

And Eratosthenes probably already knew that. The idea of a spherical Earth was floated around by Pythagoras around 500 BC and validated by Aristotle a couple centuries later.

Eratosthenes actually had it easy, he already knew of a nearby city (Syene) where the sun was directly overhead at midday on one day of the year - the summer solstice - meaning that all he had to ...

Eratosthenes measures the earth. It was around 250 BCE when Eratosthenes was a librarian in the famous library of Alexandria He discovered in his reading that there was a yearly festival in the town ...

IN Sky and Telescope of September, under the heading “Saluting an Astronomer”, Joseph R. Habes has an article which describes the method adopted by Eratosthenes for measuring the circumference ...

Eratosthenes knew that the distance between the cities of Alexandria and Syene (modern-day Aswan) was 5,000 Egyptian stadia (157.5 meters, or 517 feet).