Brian Haney, age 11, of Montogomery, Ala., for his question:
HOW LONG IS THE EQUATOR?
The equator is the great circle of the earth that lies halfway between the North and South poles. This imaginery line divides the earth into two equals parts called the Northern Hemisphere and the Southern Hemisphere. The circumference of the earth at the equator is 24,901.16 miles.
The equator is the starting point for the degrees of latitude that measure distances north and south from the equator to the poles. The latitude of the equator is zero. On a globe, the equator is also the line on which equal distances are marked to show degrees of longitude, which measures east and west distances.
Each degree of longitude at the equator equals 69.17 miles.
The location of the equator can be determined by observing the elevation of the North Star or the sun above the horizon. Allowing for slight corrections, the angle of elevation of the North Star at any given place equals the latitude of the place. Thus, at the equator, the North Star is barely visible above the horizon and has an elevation of nearly zero degrees.
At the equator, the days and nights are always of equal length: 12 hours each. This is because the circle of illumination, or the line that separates darkness from daylight, and the equator are both great circles. All great circles bisect each other or cut into two equal parts. Thus, half of the equator is always in the zone of darkness and half in the zone of daylight.
The regions of the Atlantic and Pacific oceans that lie at the equator are called the doldrums. The doldrums lie between two trade wind belts and they are zones of calm. The regions have rising air currents that produce heavy rains.
The climate along the equator varies according to altitude and the distance from the sea. In the equatorial lowlands, heavy rains and uniform temperatures are common throughout the year. But the east coast of Africa has only light rain and a long dry season. Quito, Ecuador, which lies almost exactly on the equator, has an elevation of 9,350 feet and a cool temperature.
The celestial equator is an imaginary circle that goes around the sphere in which the earth and heavenly bodies lie. It helps locate stars and planets.
The magnetic equator is the line on which ail points are equally distant from the north and south magnetic poles.
Scientists believe that the earth is like a huge magnet with magnetic North and South poles. The magnetic equator lies close to the geographic North and South poles. The north magnetic pole is near Bathurst Island, in northern Canada. The south magnetic pole is in Wilkes Land, in the Antarctic.
Scientists often call the magnetic equator the actinic line. At all points along the line, a magnetic needle will remain horizontal with no dip to either side.
A tiny nation called Equatorial Guinea is located almost on the equator on the west coast of Africa. It was a Spanish province until Spain granted it independence in October, 1968.