this post was submitted on 07 Sep 2025
683 points (98.3% liked)
Microblog Memes
10911 readers
2578 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:
- Your post must be a screen capture of a microblog-type post that includes the UI of the site it came from, preferably also including the avatar and username of the original poster. Including relevant comments made to the original post is encouraged.
- Your post, included comments, or your title/comment should include some kind of commentary or remark on the subject of the screen capture. Your title must include at least one word relevant to your post.
- You are encouraged to provide a link back to the source of your screen capture in the body of your post.
- Current politics and news are allowed, but discouraged. There MUST be some kind of human commentary/reaction included (either by the original poster or you). Just news articles or headlines will be deleted.
- Doctored posts/images and AI are allowed, but discouraged. You MUST indicate this in your post (even if you didn't originally know). If an image is found to be fabricated or edited in any way and it is not properly labeled, it will be deleted.
- Absolutely no NSFL content.
- Be nice. Don't take anything personally. Take political debates to the appropriate communities. Take personal disagreements & arguments to private messages.
- No advertising, brand promotion, or guerrilla marketing.
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
I got this far on the Wikipedia and gave up:
I went down a rabbit hole about globes and maps recently
Basically, to find the shortest distant between two places on a globe (a 'straight' line), imagine a hoop or circle round the earth that cuts it exactly in half, and rotate it until it passes through both places (still cutting it exactly in half)
That's a great circle.
There are 2d map projections that are built around this, but they only work when one of the locations is at the center of the map. So it could show the shortest distance from, say, London to anywhere with a straight line, but it wouldn't work for a route not including London
In case anyone else finds visual guides to be helpful for this sort of thing, I made a graphic to accompany your words:
Ah, okay that makes more sense! Thanks!
Another way to say it, if you cut a sphere in half and both sides are equal, its a great circle. All lines of longitude and the equator are great circles.
All that and not even one rabbit.
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.
"Locally straight" is just a mathsy way of saying "it's straight if you zoom in a bunch".