Suurympyrät

Suurympyrät are circles on the surface of a sphere whose center coincides with the center of the sphere. They are also known as great circles. A great circle divides the sphere into two equal hemispheres. The shortest distance between any two points on the surface of a sphere is along the arc of the great circle that passes through those two points.

Examples of great circles include the Earth's equator and any line of longitude when extended to form a complete circle passing through both the North and South Poles. Meridians are semi-great circles that connect the North and South Poles. When paired, two opposite meridians form a great circle. Similarly, the equator is a great circle. Any two points on the sphere, unless they are antipodal (diametrically opposite), define a unique great circle. If the two points are antipodal, then infinitely many great circles pass through them.

The concept of great circles is fundamental in spherical geometry and navigation. For instance, great-circle routes are the shortest paths for aircraft and ships traveling long distances on Earth. The calculation of these routes involves understanding the geometry of spheres and the properties of great circles. The circumference of a great circle is the largest possible circumference of any circle that can be drawn on the surface of a sphere.