Originally Posted by flyer by the wire
So between 2 points where a great circle ain't formed,we have a small circle.
The smallest circle you can draw on the sphere has the distance between your 2 points as its diameter, and the 2 points divide that circle into two equal arcs of 180 degrees. If you take either arc to get from A to B, you're not taking the shortest distance. To get that, you have to draw the greatest circle possible, which has the center of the earth as its center.
regards,
HN39