How the Earth was First Measured
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It is a common misconception that Christopher Columbus discovered the Earth was round. It should more accurately state that he contributed to the rediscovery of this fact. The ancient Greeks knew this to be true through scientific deduction, and no one more so than Eratosthenes, born in 276 B.C.E, and credited with the title βFather of Geographyβ.
So how did he make this incredible deduction I hear you ask?
When he was appointed to the position of βChief Librarianβ and the great library of Alexandria he heard of a place in modern day Aswan (Egypt) where the midday sun cast no shadow on a stick when placed in the ground (effectively a makeshift sundial). He then measured, on that exact date and time, the same effect from Alexandria and observed there was a 7.2 degree (1/50th of a circle) difference.
From this he extrapolated the distance between them and concluded that the Earthβs circumference was in the region of 250K stades, what we now know to be 28,000 kilometres. Modern measurement tells us that the exact distance is 24,900 kilometres, which means his approximation was well within the ballpark. Not bad hey?
He basically used the geometry we get taught in school and college! So howβs that grey matter then? Do you think you could do better with such a calculation?
It is a common misconception that Christopher Columbus discovered the Earth was round. It should more accurately state that he contributed to the rediscovery of this fact. The ancient Greeks knew this to be true through scientific deduction, and no one more so than Eratosthenes, born in 276 B.C.E, and credited with the title βFather of Geographyβ.
So how did he make this incredible deduction I hear you ask?
When he was appointed to the position of βChief Librarianβ and the great library of Alexandria he heard of a place in modern day Aswan (Egypt) where the midday sun cast no shadow on a stick when placed in the ground (effectively a makeshift sundial). He then measured, on that exact date and time, the same effect from Alexandria and observed there was a 7.2 degree (1/50th of a circle) difference.
From this he extrapolated the distance between them and concluded that the Earthβs circumference was in the region of 250K stades, what we now know to be 28,000 kilometres. Modern measurement tells us that the exact distance is 24,900 kilometres, which means his approximation was well within the ballpark. Not bad hey?
He basically used the geometry we get taught in school and college! So howβs that grey matter then? Do you think you could do better with such a calculation?
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Annamarie
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May 08, 2024 03:12AM
Very interesting. Numbers not my thing so I'll leave the calculation to someone else.
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Annamarie wrote: "Very interesting. Numbers not my thing so I'll leave the calculation to someone else."haha, many have said that :-)
