this post was submitted on 07 Sep 2025
703 points (98.2% liked)
Microblog Memes
9138 readers
2682 users here now
A place to share screenshots of Microblog posts, whether from Mastodon, tumblr, ~~Twitter~~ X, KBin, Threads or elsewhere.
Created as an evolution of White People Twitter and other tweet-capture subreddits.
Rules:
- Please put at least one word relevant to the post in the post title.
- Be nice.
- No advertising, brand promotion or guerilla marketing.
- Posters are encouraged to link to the toot or tweet etc in the description of posts.
Related communities:
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Another way to think about it is with elastic bands.
Imagine getting a globe and putting a pin in each place. One pin in the UK, and one in New Zealand. Now put an elastic band between those two pins so that it's tight. The elastic will be as short as possible, which is as straight a line as possible. But, since the globe is curved the elastic has to curve with it. So, that's your straight line on a curved surface.
If you wrap the elastic around the other side of the globe (you might need a bigger elastic), you can find the other half of the circle. It's the place where the elastic is at its tightest, but also where its evenly balanced between slipping to either side. For example, say you have a pin in California and another one in Japan. Both Japan and California are at about 30-40degrees north latitude. But, if you put an elastic starting in Japan and then going around the earth at 30 degrees north through China, Turkey, Spain, etc. when you let go the elastic will slip to the north until there's no tension anymore. To keep it from slipping you have to balance the tension so it doesn't slip to the north and doesn't slip to the south, so it's going flat around the whole globe. That makes the long half of the great circle.