ubutlerMar 2024Strongly recommends
One of my favourite episodes of Cosmos centres around Eratosthenes’ calculation of the circumference of the Earth: ▶ this video
in “Webb and Hubble confirm Universe's expansion rate” · View on HN
Carl Sagan - Cosmos - Eratosthenes
Carl Sagan - Cosmos - Eratosthenes on HackerTube: recommended by 4 Hacker News commenters across 4 separate months, 2022–2024.
carlsagandotcom
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A short clip from Carl Sagan's Cosmos in which he explains how Eratosthenes measured the circumference of the Earth using shadows in two Egyptian cities. It is a clear, visual account of an ancient scientific feat.
Why Hacker News recommends it
HN commenters link it whenever the question of how the Earth's size was first measured comes up, calling it a wonderful explanation.
- people recommended it
- 4
- separate months
- 4
- strong recommendations
- 1
- discussed on HN
- 2022–2024
“Here is a wonderful video of Carl Sagan explaining it[0].”
What HN commenters said
4 Hacker News comments link this video. Each one links back to its thread.
kemotepAug 2023Recommends
I heard it was using a military unit’s standard marching pace to calculate the distance. Here is a wonderful video of Carl Sagan explaining it[0]. [0]: ▶ this video
in “How was the size of Earth first measured?” · View on HN
jamesgillJan 2023Recommends
Likely familiar to this crowd, but Carl Sagan's explanation on Cosmos of Eratosthenes' discovery is great: ▶ this video
in “Interesting” · View on HN
hotpotamusFeb 2022Recommends
Carl Sagan talked about Eratosthenes in Cosmos[0] actually which is what I was thinking of. He was also able to make a good estimate of the size of the Earth as well. The video has a good explanation of how it was done. [0]( ▶ this video )
in “Zen and the Art of Talking to Conspiracy Theorists” · View on HN
Topics & tags
World historyScientific method & science communicationPure mathematicseratosthenescarl sagancosmosastronomy historygeometry