It’s a Bluesky link but he use adult tags as de facto “spoiler” tags. The problem is that content is hidden if you’re not logged into Bluesky. Here’s a Bluesky mirror site to show the entire thread…
https://subium.com/profile/c0nc0rdance.bsky.social/post/3kpkcq2ecws22
A huge hint…
My first thought was
spoiler
the Bering strait thru the arctic, it kind of requires you wait 10 years or so but I think that’s a pretty straight route
but now that I’m looking at it more
spoiler
Mercator projections are bullshit, Antarctica is really not that big, there’s probably a nearly straight line crossing thru the antarctic ocean that misses the land by a bit
As I understand it - it’s a straight line if you had a globe and you used a piece of string.
The problem is that “straight” on the surface of a globe is a curve. The map projection (how you flatten out a globe) makes that look even weirder no matter how it is done. Is any route on the surface of a globe a straight line? Does the initial question even make sense?
Of course you can have a straight line on a globe, pick a point and walk in one direction. Eventually you’ll pass a point at which your distance to a pole starts to increase again but that doesn’t mean the line isn’t straight.
The line might not be straight in the ambient 3d space but on the 2d surface it is.
The better visualization is here in that thread:
A “straight line on a curved surface” is called a geodesic. It’s the path a tiny car would drive on the surface if you didn’t move the steering wheel. Generally it’s the shortest path between two points on the surface, although that definition gets iffy for long paths that start to loop back — obviously, going 90% of the way around the equator is longer than going 10% in the other direction, even though both paths would be geodesics. I prefer the car explanation.
If you leave the UK headed southeast and keep a straight line, eventually you’ll wind up back where you started (coming into the UK from the northeast), because the Earth is spherical. If you went due south, then eventually you’d pass through Antarctica and come out the other side heading north. But if your trajectory doesn’t take you through the south pole, then you’ll still come out headed north instead of south but at an angle. If you follow the red line after where it stops, it would go through Asia and get to the Arctic and then curve back south and that’s how you’d wind up coming into the UK from the northeast. It looks like it turns but that’s only because of how things change when you project a 3d sphere onto a 2d map.
make it harder next time
