Great Circles:
Why Your Flight Path Might Surprise You

The fastest way from
point A to B

Have you ever gazed at a map, scratched your head, and wondered why your plane from Northen Europe to the US west coast takes a detour via Greenland instead of zooming straight across the Atlantic? Well, buckle up, and allow me to demystify this seemingly counterintuitive phenomenon.

First, lets talk about the Mercator map, the trusty cartographic companion that has graced classrooms for generations. Its square grid and seemingly straightforward lines make it a popular choice. However, there’s a catch: the Mercator map distorts the true sizes and shapes of land masses, particularly those near the poles. You can read more about this in my article: Greenland vs. Africa. The true size of the world.

This distortion can lead to some surprising flight paths.
Imagine you're planning a dream vacation from Berlin to San Francisco. Consulting your Mercator map, you might draw a straight line across the Atlantic Ocean, thinking it’s the shortest path. Alas, this isn’t the case! In reality, the shortest distance between two points on Earth's surface is a Great Circle route. A Great Circle is the largest circle that can be drawn around a sphere, cutting it into two equal halves. Let's take a short look at two examples.

Berlin to San Francisco

Let's take another example. On the Mercator map, a straight line from Berlin to San Francisco seems shorter. However, the Earth is not flat, and when you map the Great Circle route, it arcs northward, passing near the Arctic Circle. This seemingly counterintuitive detour is actually the shortest distance between the two cities. Remember though, great circles are just the shortest paths to follow. In reality, pilots have to take other factors into account when planning a route, such as air currents, weather, traffic etc. So, next time you're sipping your in-flight coffee up in the skies, you can impress your fellow passengers with this nugget of geographical wisdom.
Bon voyage!