Definition:Great Circle
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Definition
Let $S$ be a sphere.
A great circle of $S$ is defined as the intersection of $S$ with a plane passing through the center of $S$.
Pole of Great Circle
Let $C$ be a great circle of $S$.
Let $AB$ be the diameter of $S$ situated perpendicular to the plane of $C$.
The points $A$ and $B$, where the diameter intersects $S$, are the poles of the great circle $C$.
Axis of Great Circle
The axis of a great circle $C$ is the straight line that joins the poles of $C$.
Examples
Earth's Surface
A great circle between two locations $A$ and $B$ on the surface of Earth can be used as the shortest distance to travel from $A$ to $B$.
Also see
- Results about great circles can be found here.
Sources
- 1976: W.M. Smart: Textbook on Spherical Astronomy (6th ed.) ... (previous) ... (next): Chapter $\text I$. Spherical Trigonometry: $2$. The spherical triangle.
- 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): great circle: 1.
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): great circle
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): great circle
- 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): great circle