Carl Sagan explaining how they could figure out the world was round thousands of years ago - bestofyoutube.com

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Carl Sagan explaining how they could figure out the world was round thousands of years ago

Posted 8 years ago by Anchorman in category: interesting

Comments (7)

HoraceSPatoot - 8 years ago [ Reply ]

That's a fine explanation and conveys the basic idea, but if it were done that way, how did Eratosthenes know that the measurements of shadows were taken at the same time? The real story is a bit more complicated but just as interesting more clever in my opinion. Wikipedia has a good entry on the subject under "Eratosthenes".

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causeby - 8 years ago

Because the experiment included synchronizing times in the two places.

HoraceSPatoot - 8 years ago [ Reply ]

^^ I meant no criticism of Carl Sagan, who was a hero of science for making science interesting to people.

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(guest) - 8 years ago [ Reply ]

Not sure about time syncing, I thought it was about distance from equator? Only at equator is sun ever directly overhead for zero shadow at noon. Elsewhere shadow would reduce to a minimum at noon, but some would still remain.

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(guest) - 8 years ago [ Reply ]

History question here... The conclusion depends on knowing that the sun is so far away that the rays are essentially parallel. For someone believing that the sun is a ball sitting just above the clouds these results could've supported the idea that Earth is flat. So what was the understanding at the time about how far away and how large the sun is?

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tericath - 8 years ago

Jena (guest) - 8 years ago [ Reply ]

I know someone I will show this video to, as much as I tried I couldn't convince him that te earth is round.

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