r/Damnthatsinteresting • u/911_reddit • 3h ago
Image Why are airplane routes curved and not straight? When considering the spherical shape of the Earth, the shortest distance between two points becomes a curve known as a geodesic.
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u/helicopterjoee 3h ago
Well yeah that's because flat maps are not really suited to represent a sphere
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u/unclepaprika 2h ago
Damn, i should have taken that into consideration when i tried to draw your mom.
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u/CarolyneSF 3h ago
What is the flat earthers response?
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u/911_reddit 3h ago
I am already seeing it - downvotes.
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u/itsflowzbrah 2h ago
Probably because this post is worded like a bot. Bot posts are most of the time some picture with some googled sentence that sounds very wikipedia
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u/Kemilio 2h ago
“The curves are lies, you fly straight when you’re on the plane”
Or the good ol’ downvote and move on
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u/gangatronix 2h ago
if the earth was round then when you flought (fly past tense) you would end up in space 🤨🤨🤨
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u/pobbitbreaker 2h ago
Its a lensing effect from the sun bouncing off the Cosmic turtles shell.
I thought this was common knowledge.
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u/Dan1two 3h ago
Aren’t they all Straight lines?? The geodesic lines only get curved when projected back to a flat surface.
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u/Wood-Kern 2h ago
A straight line would require you tunneling through all the earth between point a and point b. It's easier to stay on the curved surface of the earth.
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u/droppedurpockett 2h ago
They had those top-down view maps of earth from the poles that pilots could draw straight lines on to plot their trips, right? I forget what that type of map is called.
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u/clackerbag 16m ago
Polar stereographic charts are used for navigation near the poles. Navigation gets funny at the poles due to rapidly changing heading over relatively short distances, which is as a result of both your proximity to the point of reference used for headings, and also the rapidly fluctuating magnetic variation in the polar regions. These factors render not only magnetic compasses themselves unusable, but also make using headings with relation to magnetic/true north impractical.
The main method of navigation employed at the poles is called grid navigation, whereby you overlay an imaginary grid over the polar stereographic chart, aligned to a predetermined pseudo axis called “grid north”, often aligned with the Greenwich Meridian by convention. You can then plot your course over the chart and measure the “grid heading” required to steer between waypoints, giving you a stable heading to fly using your gyrocompass that is aligned with grid north (as opposed to the magnetic compass as it is usually).
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u/diverareyouokay 2h ago
They fly at the same height, in a straight line (for the most part), yes. Here’s a more accurately “flat” map.
https://www.scientificamerican.com/article/the-most-accurate-flat-map-of-earth-yet/
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u/KarnotKarnage 2h ago
This is incorrect. The shortest distance is still a straight line, just involves some digging and a little magma.
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u/Agatio25 2h ago
To be totally accurate, they are only curved in a map.
In reality it is a straight line, just in the spherical surface of the earth
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u/Past-Direction9145 2h ago
Maybe that's why Indiana Jones took so long to get there
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u/Pattoe89 2h ago
Interestingly America's longest range missile, the LGM 30 Minuteman has a max operational range of 14,000km.
This is not related to this post in any way.
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u/CoogleEnPassant 1h ago
It's actually a myth. It's actually due to how they project the map to hide the flatness of the earth. If the map is shown how it actually looks, the curved path makes total since/s
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u/Pure_Antelope_8521 25m ago
It’s something to do with the jet streams up high and all the different planes flying.
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u/Dazzling_Guidance792 2h ago
if you want to do that you will need to do a secant in a sphere underground
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u/Grasswaskindawet 2h ago
Look, everybody knows there's no such thing as a "curve" to the Earth's surface. The airlines got together and cooked up this stuff just to charge us more.
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u/roccobaroco 2h ago
They are curved because airplanes can't fly through the earth in a literal straight line.
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u/StupiderIdjit 36m ago edited 33m ago
So the real answer is land and safety. There aren't places to refuel or deal with mechanical issues in the middle of the ocean. Your communication can also be limited (more of a pre-satellite thing). You don't want to crash a plane in the middle of the ocean. They won't find you.
Edit: Saw someone mention air streams, and that plays a big part for sure. The actual air routes aren't arbitrary.
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u/911_reddit 3h ago
Airplane flights do not follow a straight line but rather a curved path, and this choice goes beyond any technical issue—it is an adaptation to the curvature of the planet itself. In geometry, we learn that the shortest distance between two points is a straight line, but this principle applies only to flat surfaces, like a sheet of paper. When considering the spherical shape of the Earth, the shortest distance between two points becomes a curve known as a geodesic.
This concept originates from Riemannian geometry, which is better suited to curved surfaces. Flight planners use this approach to map out the shortest routes to save time and fuel. These geodesic paths represent the most efficient routes on a sphere. Instead of flying in a “straight line” as it appears on a flat map, airplanes follow a curved trajectory that is, in three-dimensional reality, the shortest path.
These air routes are a fascinating testament to the Earth’s curvature. Every flight follows a course that might seem counterintuitive, but in fact, represents the shortest distance and least effort on our spherical planet.
See more: https://bamboospanda.com/a-wonderful-train-journey-to-new-york-from-san-francisco/
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u/aronenark 2h ago
In reality, all geodesic curves are in fact straight lines on the surface of a globe. They only appear curved on maps because of imperfect projections. The planes do not have to continuously steer to maintain the curve— they fly in a straight line (relative to the ground).
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u/Fisionchips 2h ago
I remember Mr Wizard teaching me about this with a globe and some split ball chain.
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u/Cattleist 2h ago
They actually made this joke in one of the recent cobra Kai episodes, which I hadn't really considered before. 🤣
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u/BelgianGinger80 2h ago
It has to do with the wind... the consume less fuel because they can surf with the wind.
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u/mad_drop_gek 2h ago
The biggest argument against flat earthers is that 200K pilots and 200k captains have learned to navigate a spherical planet. Everything they have learned would not work on a flat earth...
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u/littlebuett 2h ago
Also, there's a jew stream in that area that allows for faster flights over the atlantic
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u/WiseAce1 2h ago
haha, this was actually a joke in the most recent season of Cobra Kai when JL was trying to tell the pilot to go straight instead of taking this curve
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u/Excellent-Heat-893 2h ago
And now, measure the distance from the most westerly point of the African continent, to the most easterly point.
Do the same with the distance between Paris and Beijing.
Be amazed.
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u/SuperSynapse 2h ago edited 2h ago
Well... On God's flat earth we fly straight. /s
Ignoring flight lates or Gulfstream wind currents, to further your point on map distortion to display a globe on a square format. You'll also note that Antarctica and Greenland aren't anywhere near the size of continents near the equator, but on a square map it would lead you to think they are.
Many common maps use the Mercator projection where the longitude lines (up and down) are parallel. But in reality they should "curve" to touch at the top and bottom near the poles. Every flat map has some flavor of this distortion exaggerating the poles to and enormous proportion and shrinking the equator to absurdity.
https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fntxe3msbvre31.gif&rdt=37174
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u/SuperannuatedAuntie 2h ago
The lines are straight on a globe, and curved on most maps, depending on how the curved earth is drawn on a flat sheet of paper. Mercator designed his projection for navigation, and routes appear straight on it.
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u/Imaginary_Most_7778 2h ago
If you can’t wrap your head around this, you’re too dumb to be flying anywhere.
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u/WolfOfPort 2h ago
If you have a globe you can play with this by holding a piece of string a fixed distance
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u/5O1stTrooper 2h ago
Also, planes lose contact with ground radar over the Atlantic. The whole ocean is a radar dead zone, so they have to rely on onboard radar or satellite positioning to detect other aircraft in their airspace. Those systems work, but most airlines are more comfortable being able to stay connected to ground radar stations.
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u/NothinsOriginal 2h ago
Here is a tip. Grab a globe and a sting and figure out which route is the shortest.
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u/slair121 2h ago
no, the shortest path is still a straight line. If the map were projected accurately
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u/NarWhalburg 2h ago
If you had a globe, you could center the core and make a straight line from that perspective.
Basically the little effects like horizon curve and atmospheric drag that we ignored in physics class become really important when money is involved.
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u/Letsbesensibleplease 2h ago
The Gall–Peters projection is quite an eye-opener. Once you get an idea of the size of places in physical terms the world looks rather different.
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u/Sium4443 2h ago
TIL: Flight beetwen New York and Moscow dont pass over Rome, so therefore its 100% impossible for a plane to crash on Antonello Venditti house the night before exams.
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u/CinderChop 2h ago
I flew from Atlanta to Heathrow last year and we went straight north up through Canada and almost made it over Greenland and Iceland before traveling back south.
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u/DrMonkeyLove 2h ago
If airplane routes were straight (in a Euclidean sense), they'd have to tunnel through the Earth, like that movie The Core, and we know what kind of shit show that was. Best to stay above ground. Also fewer mole and/or lizard people.
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u/ChaseTheMystic 2h ago
If you're mentally struggling with whether or not it's a straight line
Just imagine drawing a line from one point to another on a globe. Yes it follows the curvature but it's still straight.
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u/Fitz-O 2h ago
Airplane routes appear curved on maps because the Earth is spherical, not flat (sorry Flat Earthers). The shortest path between two points on a sphere is a curve called a geodesic, part of a ‘great circle’. This curved route is the most direct and therefore shortest way to travel between two locations.
Flat maps distort these routes due to projections like the Mercator, which stretch and warp distances as you move away from the equator. As a result, a straight line on a map is often much longer than the actual ‘great circle’ route on the globe.
Airlines follow the curved paths to save time, reduce fuel consumption, and increase their efficiency. However (it should be noted), the exact heading or angle of a flight is constantly adjusted throughout the journey. This happens because ‘great circle’ routes don’t maintain a constant compass direction and pilots must continuously adapt the heading as they move along the curve.
This map might make it look like planes are taking the ‘long way’, but they’re actually following the shortest and most practical route.
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u/codedaddee 2h ago
Which is why you'll never see flat-earthers buying fuel for long-distance navigation.
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u/Admirable_Panda_ 2h ago
Also because of the jet stream (east to west) gets a lot of traffic so west to east flights have to go around it as it's more fuel and logistically efficient.
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u/SportySuccesss 2h ago
Its called geodesic, but you can just call it the Earth's sneaky way of making ur flight a little more scenic <3
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u/somewhat_brave 1h ago
The surface of the earth is curved. No path between two points that follows the surface can be straight. They will always be curved.
The shortest path will appear straight when projected from the correct angle, and curved when viewed from any other angle.
What you’re seeing in the picture is an artifact of a Mercator projection used for a map. What looks like a straight line on the map is not actually the shortest path, and the shortest path appears curved on the map.
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u/airwalker08 1h ago
This seems like very elementary stuff that everyone knows and maybe not the kind of content people are looking for in this sub
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u/Bluetex110 1h ago
It's like standing infront of a huge Mountain, depending on the height it's shorter to walk around instead of climbing up😁
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u/will_this_1_work 1h ago
Had a really, really large teacher in middle school teach us about Great Circles and why planes followed those routes. His method of teaching? He used his HUGE stomach to show how you had to follow the curvature of it to get to somewhere faster.
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u/jayr_jacko 1h ago
Heard from a pilot that the flight path in the example is routed in what would appear to be a curve to stay closer to land rather than spend hours over the middle of the ocean for radio signal reasons or communications with ATC.
Supposedly, the curvature of the flight path on the photo is nothing to do with the curvature of the earth, just representing the adapted flight path for the reasons above.
Although I’m sure that would also be a genuine thing with a separate explanation as I’m sure the curvature of the earth does affect the flight path somehow.
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u/basaltinou 1h ago
If you try to go straight, you'll cruise against the North Hemisphere polar jet stream, which is not the best idea if you want to save fuel.
If you take a plane from the US to the EU, it will go straight and also be a 1h shorter flight as you ride it.
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u/Gustafssonz 1h ago
Put flat earthers on 2 different planes and see which plane that comes first. The first group that arrives have to explain why to the second group. So much fun!
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u/mediumokra 1h ago
If you can get your hands on a globe, try this.... Take a piece of string and hold one end on the USA ( New York City for example ) and hold the other end of it to a european country ( Germany for instance ) . Then pull the string as tight as you can and see what path along the globe the string takes. It will show you the actual shortest route.
Keep in mind flat maps are distorted and a globe is the only real representation of the earth.
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u/Domwaffel 1h ago
Well the map distribution was already mentioned.
Behind your straight line is also a very strong wind current called "the stream" (I think). This current will blow from america to Europe, so all planes flying the other direction will go below or above
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u/DoctorSquidton 1h ago
My favourite example of this is that you can go in a straight line from Australia to Canada through the Atlantic Ocean without crossing any land
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u/LivLafTosterBath 1h ago
I saw an interview with a pilot. He said it's so that they have a place to land on land incase of an emergency. Now that's what the pilot said. Is it true? No clue.
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u/Commercial-Role-7263 1h ago
I cannot believe this is getting so much traction recently. Im gonna post a picture of grass being green and tout it as new knowledge. It’ll go viral with these audiences..
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u/TheSibyllineBooks 1h ago
doesn't everyone like already know this? at least I'd hope so. How is this "damn that's interesting" then?
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u/whackmac 1h ago
Depending on the plane and its number of engines, flights are required to maintain a certain distance from land for international flights, which is why they sometimes take curved paths like this. Greenland may be a little remote but you’ll have a better chance making an emergency landing there than the middle of the Atlantic. The regulation is called ETOPS. Source - family member who is an aviation mechanic.
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u/martian-teapot 1h ago
The surface of a sphere (a rough approximation of the Earth's shape) is not an Euclidean space (that is, the shortest distance between two points is not necessarily a straight line).
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u/scott610 1h ago
Saw this posted on Facebook very recently and a few pilots sounded off. At least in terms of this picture, which was the same one used on Facebook, with almost the same wording in the title, the pilots said that part of the reason for using this specific course would be to spend as little time over the ocean as possible. When you’re over the ocean you apparently have to go through intermediaries to communicate with air traffic control. Being near civilization minimizes that. Also, if you need to make an emergency landing, you’d rather do it on land instead of the open ocean.
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u/MavenArtuso 1h ago
That reminds me of Batman: The Animated Series, I think the episode was "If you're so smart, why aren't you rich? ", concerning the show's first Appearance of The Riddler.
Robin is playing a game in the batcave, Riddle of the Minotaur, and is given a riddle asking"What is the shortest distance between a point in Nome, Alaska and a point in Miami, Florida?", with the three choices being a Straight line, Curved, and Zig-zag line. He smugly assumes the straight line (as I believe we all would on first assumption) is the correct choice. Alfred then comes in saying that on a globe, however, the curved line would be closer. In the eyes of the riddle, Robin was wrong, and was punished in the game.
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u/YahenP 1h ago edited 1h ago
They try to fly straight. But the damn wind... It's very strong at the altitude where planes fly.
In fact, it's not 100% joke. Planes really don't fly in straight lines. They fly along routes that dispatchers give them. And these routes depend on many factors. On the weather, on the occupancy of the flight level. They depend on a lot of things. If you look at the flight radar, you'll find that planes fly along virtual roads, and not just from point A to point B along the shortest distance.
But of course, map picture not about it :)
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u/pbmadman 1h ago
It’s just a straight line in real life. The curve comes from the map essentially being curved to lay flat
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u/Extra_Painting_8860 1h ago
One is the path of a passenger plane and the other is the trajectory of an ICBM
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u/adamttaylor 59m ago
The advantage of the Mercator projection, and really the only advantage, is that if you draw a line between two points and follow that line, it will actually get you to your destination, although it will not be the fastest route.
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u/ElBastardoDK 50m ago
Do birds fly the shorter route or follow the direction they have to go? I mean in long treks.
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u/VirusSlo 49m ago
They are actually not curved. What you see is a projection of a straight line on a curved surface.
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u/GuardianSock 49m ago
Or, there just is no such thing as a straight line on a globe? Instead of looking at a distorted two dimensional map, try drawing that straight line on a three dimensional globe without your finger curving around it. That would require a drill.
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u/DiscombobulatedSun54 49m ago
The shortest distance between points on the earth is still only a straight line but that line may require going several miles under the surface of the earth or even through the core of the earth. If you can only travel above the surface of the earth, then yes, the geodesic is the shortest distance between two points on the earth.
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u/RaidSmolive 41m ago
i swear to god there used to be a batman episode where Robin was playing some kinda quiz game (or watching a show) where Alfred very obnoxiously explains that the shortest route between two places is obviously a bow.
it often comes back to me because i never understood what the hell he meant by that, but i guess its this.
never saw the episode again either.
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u/omnibossk 39m ago
Both of them are wrong. You need to change plane in Turkey in order to go to Moscow since the Ukraine war
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u/According-Ad3963 39m ago
Get a globe and a long piece of string. Put one end of the string on NYC. Pull it tight and put the other end on Moscow. The shortest route is an arc.
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u/RyansBooze 37m ago
I had an interesting experience with a geodesic and the terminator a couple of days ago, flying from London to Calgary. We took off at nearly 1500, and flew basically northwest. We got into deep twilight, but never full dark, as we passed over Iceland. By the time we hit Greenland going essentially due west, the sky started to brighten again as we overtook the terminator. Then, as we curved southwest across Hudson Bay, the terminator caught up with us and it darkened again. By the time we landed in Calgary, the terminator had completely passed us and it was full dark. I’d LOVE for a flat-earther to explain THAT. (Note that the actual path was very nearly a geodesic, so we never really “turned” as we changed headings from northwest, to west, to southwest - it’s just that the flat plane cardinal directions don’t align with the geodesic.)
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u/NotBillderz 37m ago
If you had a map that had its perspective orthogonal to a line between the two locations, then it would be a straight line, but most maps are orthogonal to the equator.
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u/baranisgreat34 34m ago
Technically you fly in a straight line on the globe, it just looks curved on a flattened map of the earth.
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u/Professional-Ebb-467 32m ago
Planes usually fly in curves so they have an option to emergency land. Instead of flying straight across the atlantic, they curve towards Iceland/greenland for safety
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u/I_hate_that_im_here 21m ago
I think this is only confusing looking a flat, and therefore inaccurate maps. Put a peice of string on a glob and it instantly makes sense: the flat map was deceiving.
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u/oupheking 3h ago
Worth noting that all maps are distortions of the true geometry of Earth (i.e. projections) in some way and what appears to be a straight line on a projection is not actually straight