31–40 of 122 posts
I always struggled (and still struggle) with math. A couple of years ago, randomly browsing YouTube, I came across this home made video asking how they figured out the distance to the moon before modern technology. The host starts out small scale showing he can calculate the distance to things in his back yard using trigonometry and then scales it up to the moon. My mind was blown, because no one ever told me that. I…
I always struggled (and still struggle) with math. A couple of years ago, randomly browsing YouTube, I came across this home made video asking how they figured out the distance to the moon before modern technology. The host starts out small scale showing he can calculate the distance to things in his back yard using trigonometry and then scales it up to the moon. My mind was blown, because no one ever told me that. I…
Eratosthenes was (IMO) pretty amazing in the range of interests and accomplishments: https://en.wikipedia.org/wiki/Eratosthenes His name came up recently on another post on a very different topic: https://news.ycombinator.com/item?id=37236099
A truly fascinating polymath, it must have been so satisfying to identify previously unsolved problems, and come up with a solution for them that were more or less 'good enough'. I wonder what he would have made of the way we are today, or if he were born in this era, what kinds of problems he'd have identified that needed solving.
I always struggled (and still struggle) with math. A couple of years ago, randomly browsing YouTube, I came across this home made video asking how they figured out the distance to the moon before modern technology. The host starts out small scale showing he can calculate the distance to things in his back yard using trigonometry and then scales it up to the moon. My mind was blown, because no one ever told me that. I…
Which video?
> the distance from Alexandria to Syene -- believed to have been about 515 miles Even this part sounds amazing to me. How did they measure distances this long back then?
This is in every encyclopedia ever... I'm amazed when people don't know this (!) Next we will hear about Ptolemy... then Galileo :)
I always struggled (and still struggle) with math. A couple of years ago, randomly browsing YouTube, I came across this home made video asking how they figured out the distance to the moon before modern technology. The host starts out small scale showing he can calculate the distance to things in his back yard using trigonometry and then scales it up to the moon. My mind was blown, because no one ever told me that. I…
> the distance from Alexandria to Syene -- believed to have been about 515 miles Even this part sounds amazing to me. How did they measure distances this long back then?
A very long piece of string.
This was paced.
Earlier quoted context omitted.
Land along the Nile was heavily surveyed, yearly, to ensure its course changes were recorded in landownership. > Long distances were measured by professional distance walkers, called bematists, who walked at a very regular pace and counted each step. Shorter distances were measured with lengths of knotted rope by men called harpedonaptai, which means “rope stretchers” https://www.maa.org/press/periodicals/convergence…
Staking claims, where corner posts were placed at half kilometer intervals, were usually paced on foot, estimating for canyons, stream crossings, and other diversions. Some claims were continuous up to 20km by 20 km. This was in complete wilderness, in the Yukon, British Columbia and so on. Pre GPS. Not that long ago! They used topographic maps for reference. It is amazing how accurate the claims were, when transferr…