Any circle on the Earth's surface whose center is at the center of the Earth is called a "great circle".
Any circle with its center anywhere else is called a "small circle".
Spiritually, many consider the kaaba (Mecca) to be the center of the Earth's surface.
Yes.
Every so-called "great circle" is (more or less) the longest circumference of the Earth that includes any two points. The great circle includes the shortest distance between the two points for travel along the Earth's surface.
on the surfaceNote:Since the earth's composition is not homogeneous, the gravitational acceleration onthe surface is probably less than what it is some small distance below the surface,but it's certainly greater than at the center.
That's the Earth's radius. It's about 6378 kilometers at the equator. That's 3963 miles.
The Astronomic symbol for the Earth is a circle with a cross in the center of it.There is an example on this website:http://en.wikipedia.org/wiki/File:Earth_symbol.svg
The equator is an imaginary circular line around the entire earth, with the center of the circleat the center of the earth.Any circle that has its center at the center of the earth divides the earth's surface exactly in half.
That would have to be at a radius that is sqrt(26) = 5.1 times the Earth's physical radius, or about 32,486 kilometers (20,186 miles) from the center.
A "great circle" is any circle on a sphere whose center is also the center of the sphere. The shortest distance between two points on the surface of a sphere is a piece of the great circle on which both points lie. A "small circle" is any circle on the sphere that's not a 'great' circle.
the center of the earth
due to volcanics effects and movement of earth which affect the earth surface
An object that is stationary on the earth's surface moves in a small circle, unless it's on the equator when it moves in a great circle.
An object that is stationary on the earth's surface moves in a small circle, unless it's on the equator when it moves in a great circle.