The equator is the imaginary line or a great circle which is on the surface of the earth which is equidistant from the South Pole and the North Pole and divides the earth into the Southern Hemisphere and the Northern Hemisphere. It intersects the surface of the sphere with a perpendicular plane to the axis of rotation that contains the center of mass of the sphere. 40075 km is the length of the equator. Equators have been defined similarly for other astronomical bodies and planets in spherical in shape.
Zero degrees in the latitude of the Equator. The earth has five circles of latitude that are noticeable out of which one is the Equator. The other circles of latitude include the two Polar Circles, Tropic of Capricorn and the Tropic of Cancer. When the equator of the earth is projected on the sky it is termed as the imaginary circle or the celestial equator. Some of the places or regions falling in the equator are the Potianak town in Indonesia and Nanyuki in Kenya.
Twice a year the sun passes over the Equator directly at the equinoxes in September and March. Sun rays fall perpendicular at the equator to the earth’s surface during the equinoxes. Regions at the equator experience the sunset and sunrise at the quickest rates. At these places the sun goes to the nadir from the zenith and to the zenith from the nadir. All through the year, these places get twelve hours of sunlight with a variation of just a few minutes. At the Equator, the Earth bulges.