Since the Earth is a sphere (shaped like a ball), there are many
different directions you could follow from New York and end up
in Istanbul.
For the SHORTEST trip, you'd want to start out from New York
on a heading of 50° east of North. That's very close to the direction
of northeast, and it aims you almost exactly toward Boston.
You would fly over New Haven, Connecticut, then Boston, then Labrador
and out over the Atlantic Ocean. Crossing Europe, you would come very
close to flying over Dublin, London, Brussels, and Belgrade, and then come
into Istanbul from the northwest. The total distance of your trip is almost
exactly 5,000 miles.
If you look at a flat map in a book, you might think you should go straight
East, and you would wonder how going northeast could make the trip
shorter. To answer this question, find a globe of the Earth in the library
or one of the classrooms in your school. Find New York and Istanbul on
the globe, and then stretch a rubber band between them. A rubber band
will naturally take the shortest distance between them, and you'll see that
the route is just as I've described it.
