THE VIDEO SHELF · measuring earth's circumference
Carl Sagan - Cosmos - Eratosthenes
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 HN readers recommended it
HN commenters link it whenever the question of how the Earth's size was first measured comes up, calling it a wonderful explanation.
This is a summary from the source dataset, not an endorsement by Hacker News or the video creator.
Video & recommendation details
- Creator / channel
- carlsagandotcom
- Topic
- measuring earth's circumference
- Format
- explainer
- Level
- general
- HN recommenders in dataset
- 4
- HN mentions in dataset
- 4
- Recommendation years in dataset
- 2022–2024
These counts and years describe the included Hacker News records; they are not YouTube views or the video’s publication date.
From the original HN conversations
Excerpts from the recorded comments. Follow each source for the full comment and surrounding discussion.
One of my favourite episodes of Cosmos centres around Eratosthenes’ calculation of the circumference of the Earth: [VIDEO]
ubutler on Hacker News · 2024-03
In Webb and Hubble confirm Universe's expansion rateCarl 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]( [VIDEO] …
hotpotamus on Hacker News · 2022-02
In Zen and the Art of Talking to Conspiracy TheoristsLikely familiar to this crowd, but Carl Sagan's explanation on Cosmos of Eratosthenes' discovery is great: [VIDEO]
jamesgill on Hacker News · 2023-01
In Interesting
Summaries, classifications and recommendation records are from the HackerTube source dataset. Read about this library and its limitations.