What is a great circle?

Question

What is a great circle?

Answer 1

The simplest way to think of it is like this:

Slice a globe with a knife. If your knife passes through the center of the globe, the cut it makes on the surface will be a great circle. The cut doesn't have to go in any particular direction, but it must pass through the center of the earth. If your knife misses the center, the cut will also be circular, but it will be a "lesser circle."

As mentioned before, the shortest path between any two points on a sphere will always be a great circle.

Answer 2

Gebobs is pretty close. He is referring to what would be a "great circle route" which always follows along a "great circle".

A great circle is a line you might draw around a sphere starting and ending at the same place--a circle--which is straight and goes through the original starting point's antipode, that is, absolutely opposite point on the globe. The equator is one of these. If you were to walk absolutely straght all the way around the globe with no deviation, you would find yourself back at your starting point eventually and you will have taken a great circle route.

Important: Compass directions are meaningless in figuring out what these are--it'll only confuse you. Trust people when they say that the fastest way from New York to Japan is over the Arctic Ocean.

Answer 3

A great circle is a circle, which, even having only humble beginnings, rose above the mundane and the mendicant, and served for the greater good of geometry. Such as a circle on a sphere. Particularly those circles on a sphere that which any arc of the great circle is the shortest distance between any two points on a sphere. Like routes airliners take in going from city A to city B. The equator is an example of a great circle, but a great circle can be at any direction, so long that the center of the circle is coincident with the center of the sphere. That's how an ordinary unknown circle can hopefully rise to greatness. It just takes persistence and a belief in one's self.

Answer 4

A great circle is the shortest path between two points on a sphere. When superimposed on a flat map, these paths look to be curved, but are actually shorter than the straight line on the map.

East-west great circles appear as an arc on flat maps with the endpoints closer to the equator than the midpoint. Similarly, north-south great circles appear as an arc with the endpoints closer to the prime meridian than the midpoint.

Answer 5

a circle on the surface of a sphere which lies in a plane passing through the sphere's centre. As it represents the shortest distance between any two points on a sphere, a great circle of the earth is the preferred route taken by a ship or aircraft.

Answer 6

It probably is referring to the Great Circle Routes that airplanes fly. Since they fly over a curved Earth, if you plot their route on a flat map it looks like a half circle.

Answer 7

any line of longitude and the equator