If you are going to fly from San Francisco to Tokyo or from Paris to Washington DC you might think that your flight will take the straight routes across Pacific or Atlantic Oceans as the shortest route. Because the shortest distance between A to B is a straight line, isn’t it?
Yes, that’s true, but actually, mostly airplanes flying from the West Coast of America to Asia or from Europe to America, Africa to Australia would take a curved route (Great Circle) and pass over the northern or southern parts of the globe. So what’s up then, why don’t airplanes fly in a straight route?
First of all, we need to think in 3 dimensions and forget about the flat maps. Just because, in a 2 dimensions map (flat map), the straight line is not the same as in 3 dimensions one, simply because our planet is not flat. You can test it yourself with the globe Earth model and try to connect two cites halfway across the world with the string. You’ll find out that curved routes are physically shorter. So that’s why the airplanes make curved routes to travel from A to B, as in a 3-dimensional space it is the shortest route and is called geodesic or great circle route. Now any line that goes through both North and South Poles are Great Circles as the Poles are opposite each other. That’s why sometimes you should head farther north or a little south to reach your destination. So now while reading this article check the flight, say, from Cape Town to Sydney which are the same latitude and conduct the experiment with the globe model, and compare it with the flat map, see the results?
Next time if you plan your trip to any destination by plane, don’t be surprised that you are going to have a curved route, this is all about our planet structure.
Until next time, and as always, “We Speak Aviation.”