Jennifer Pindlay, age 11, of Sag naw, Michigan. for her question:

What is a Great Circle Route?

la map is a flat diagram of the earth's surface. And the surface of the earth is a globe. An old style map is plotted on equal squares of latitude and longitude. But on the real globe, these sections taper off towards the poles. Hence, the width of Greenland is stretched way out of proportion. The map shows direction correctly. But the distances are stretched way out of proportion.

Sailors and pilots need a map to show the shortest distance between two points. Europe is way east of California. But is due east the shortest way to Europe from California? It may not be. Remember the earth is a globe, the journey is always over a hump or curve.

An air map must plot the shortest distance over the curved surface of the earth. On a flat map, this must show as an arc. If continued, the arc forms a great circle right around the globe. This great circle map often shows that the shortest distance between two points is not where you expect it. The shortest distance between Northern California and Europe may be right over the North polar regions not due east but north, then south.