The shortest distance
The shortest distance
102 comments
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The word "can" Is doing some heavy lifting here. I mean, there is a difference between theoretically possible and actually being done.
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[PROCEEDS INTO HURRICANE]
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Dexter?
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Anf also probably a bit of the antarctic ice sheet
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Yeah, it's going through the most dangerous water passage in the world IIRC, between South America and Antarctica. We do go through it fairly regularly at this point, but it's still not "safe."
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Don’t the circumpolar winds essentially prevent this, or at least make it really impractical?
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"sail"
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That southern ocean is brutal tho
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Especially going the wrong direction!
It'd be less bad on the return trip, but then you're fighting the trade winds and the Canary current instead.
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Just rename it as Pacific Ocean and voila, no storm hence the name!
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Even better, imho, you can sail in a direct line from OG Zeeland (Netherlands) to New Zealand.
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Can you, though? You'd have to squeeze through the narrow English Channel first, and that would probably require some turns.
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Now all we need is some insane person with a kayak.
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I volunteer— not like you go through most dangerous sea passage in the world or anything…
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If it makes you feel better, the line is actually curved along the surface of the earth, you know, if you believe in a spherical earth.
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Nah. I've come to believe it's shaped like Dick Cheney's black, twisted heart.
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A void doesn't have a shape
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The earth is obviously a sac of 1 dimensional space.
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There is also a route that can be drawn from Halifax, Nova Scotia on the Canadian east coast on the Atlantic ... head a bit south east and without touching land and only going over the ocean, you can end up on the west coast of British Columbia, in Canada on the Pacific coast.
I used to reference a website that showed that ... but now I can't seem to find it. :(
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Another fun one is to ask someone if they were to take off in an airplane from Miami and fly due south, which South American countries would they fly over?
The answer is none of them. You end up missing the entire continent because you are too far west.
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You hit Panama first, but small portions of Ecuador and Peru are west of Miami (80.2 degrees west). The broader point that South America is much farther east than many Americans think is definitely true, though.
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???? ... da fuck??? .... I was going to correct you when you said "too far west"
Now my brain is broken :(
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I looked at that on Google Earth, now I'm uncomfortable in two directions...
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I tried replicating this with Google Earth, but once you get past the halfway mark it tries to flip around and draw a line in the other direction. Guestimating it by drawing two lines seems to work ok, but I can't find a way to avoid Australia, while shifting the start and end points between northern and southern NS and BC, and keeping the midpoint either just missing Africa or just missing Antarctica.
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There used to be a website or post where I originally saw this .... I can't find it any more. And there are no more easily accessible websites that can diagram maps with 'great circles' on a globe. This was ten years ago and it used to be easy to find this stuff ... interesting to see that most of those sites are either now gone or don't work any more.
But from what I remember, the line between Halifax and the west of Canada skirted the edge of Africa and the edge of Australia to make it across the globe without touching any land mass or island.
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I got this far on the Wikipedia and gave up:
On a curved surface, the concept of straight lines is replaced by a more general concept of geodesics, curves which are locally straight with respect to the surface. Geodesics on the sphere are great circles, circles whose center coincides with the center of the sphere.
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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
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In case anyone else finds visual guides to be helpful for this sort of thing, I made a graphic to accompany your words:
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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.
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Ah, okay that makes more sense! Thanks!
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"Locally straight" is just a mathsy way of saying "it's straight if you zoom in a bunch".
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Hopefully someone shares this with Geowizard, ultimate straight line challenge.
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You can also build a nearly straight railway going from California through Canada and Alaska all the way to China.
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That'd be awesome. That probably wouldn't work because it would take 100 years for California to build their first high speed rail
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You can plot a course in a straight line. Unfortunately, weather.
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I'm no sailing historian, but that's probably how they actually discovered New Zealand.
"Heya mates, how'bout we be goin' straight ahead 'til back'ome we arrrggggh!!"
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The Polynesians took the long route.
The European explorers actually took a very similar route, so this seems to be an obvious option for sailors doing island hops in that area.
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Straight line? That looks hella curved, innit? Can't fool us with a globe. A flat map, maybe. But not a globe. Despite it being a 2D representation of a globe
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If it doesn't look right, change the way the data is presented and projected.
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A great circle. It only works on a globe.
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Comms Officer: Sirs, we still have quite a bit of time to change course.Red: But we're going straight.
Purple: Yeah. Turning's no fun. Why is this happening? Make it not happen.
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One of the few world maps with New Zealand on it.
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Only with an icebreaker
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Hum, so it's a straight line, but it's curved, and the compas turns half way.
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Well, yeah..if you want a line that is straight in 3 dimensions then any point on earth at sea level to any other point earth at sea level will require you to go below the surface of the planet.
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Y'all, I found the Flat Earther!
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Don't make fun of flat earthers, their ideology is spreading all over the globe!
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This is my new favorite globe trivia.
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straight line
So the azimut you set to your compass would be a constant, right??
/s/j
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It’s a geodesic; a straight line in spherical geometry.
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Fun fact, the UK is about the center of the land hemisphere and new Zealand is about the center of the water hemisphere
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Math nerds are going to have a field day with this statement haha.
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This isn't actually surprising, like in a vacuum it is but when you conceder that each point on earth has a full 360 degrees of points that means a line can be drawn to every possible point on earth unless something happens to be in the way, the Earth's surface is 70% water so you only have a 30% chance of hitting something that is already low but it gets much much lower since we know this is cherry picked as the most exaggerated example you only need one instance on the entire earth of a point that can reach around it out of all the infinite points.
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30% wouldn't be a lot if the land were all even-sized islands, but it's all in big chunks; most of which is in a pair of unbroken masses that runs from more or less the North Pole to the Drake Passage. There aren't any straight lines from the British Isles to Hawaii or to Indonesia, or even to Australia if I'm doing the geography correctly; nor are there any straight lines from Madagascar to Greenland, or from Iceland to anywhere in the Pacific, at least by liquid water.
Add in the fact that we're not used to seeing the roundness of the Earth from any perspective other than along the equator and split on the date line, and it's really just something that puts two things into a category together that don't seem like they should be connected.
It's like the fact that Mercury is (on average) the closest planet to Venus, but also to Earth, Jupiter, even Neptune. Ok, yes, that shouldn't be a surprise, because it's the closest to the sun and the sun is always in the middle; but it's not the way we usually look at the Solar System, and also we know that Neptune is so far away from Mercury that it's mind-boggling that Mercury could ever be the closest planet to it. It's very unintuitive based on our usual perspective and existing understanding.
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/kyr'sɛd/?
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why do we have to frame info as "cursed"? so cringe
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It's not cursed, it's bussin frfr
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102 comments
in case there are others like me who have to see what it looks like on a Mercator projection map:
Wow. I can't believe my perspective of the world is that distorted. It makes me want to only look at it in 3D. If we've all mainly looked at Mercator projections our whole lives our sense of where everything is relative to everything else and what direction is completely off.
People complain about the proportional sizing of Mercator but the sense of direction it gives us is completely broken. I think the average person knows it's off and people think there is an error factor to consider that a really straight like might be a little squiggly. But nope. This made me realize the Mercator gives pretty much zero accurate sense of direction if real distance is involved.
With respect, this is silly. People complain about the proportional sizing of the Mercator projection because disproportionate sizing is literally the only problem with the Mercator projection.
The sense of direction being off has got literally nothing to do with Mercator. That's an inherent drawback of trying to project a three dimensional globe onto a 2D image. Literally every single projection has this exact problem, in one form or another. It is considered ot be an acceptable trade-off for not having to work with globes all the time.
Stop looking for yet more baseless reasons to bash the Mercator projection, which is a perfectly reasonable and acceptable projection to use within its intended usecase (which this specific example literally is).
Short distances are fine, and obviously directly east/west are fine. Directly north/south is also pretty alright, but, as you move further from the equator, any east or west movement is covering less distance, and vice versa.
So would there be turning involved still orrrrr?
You're constantly, gradually turning downward, technically.
no, that's a straight line
No. Similarly, if you look at how planes fly, they fly in what looks like arcs, going north and then back south. On a mercator projection in looks longer, but it is the shortest straight (ignoring the curve of the earth) line.
https://en.wikipedia.org/wiki/Great-circle_distance
Can we have a map projection/grid system where this uh, great circle, is the prime meridian, defines the new 'poles' via another 90 degree orthogonal great circle that touches both actual poles?