# Why are lines of latitude also called parallels

A needle is fixed through the globe in a tilted manner, which is called its axis. Two points on the globe through which the needle passes are two poles – North Pole and South Pole. The globe can be moved around this needle from west to east just as the earth moves. But, remember there is a major difference. The real earth has no such needle. It moves around its axis, which is an imaginary line. Another imaginary line running on the globe divides it into two equal parts. This line is known as the equator.

## Why are lines of latitude also called parallels

The northern half of the earth is known as the Northern Hemisphere and the southern half is known as the Southern Hemisphere. They are both  equal halves. Therefore, the equator is an imaginary circular line and is a very important reference point to locate places on the earth. All parallel circles from the equator up to the poles are called parallels of latitudes. Latitudes are measured in degrees.

The equator represents the zero degree latitude. Since the distance from the equator to either of the poles is one-fourth of a circle round the earth, it will measure of 360 degrees, i.e. 90°. Thus, 90 degrees north latitude marks the North Pole and 90 degrees south latitude marks the South Pole. Why are lines of latitude also called parallels

As such, all parallels north of the  equator are called ‘north latitudes.’ Similarly all parallels south of the equator are called ‘south latitudes.’ Why are lines of latitude also called parallels

### IMPORTANT PARALLELS OF LATITUDES

Besides the equator (0°), the North Pole (90°N) and the South Pole (90° S), there are four important parallels of latitudes

• Tropic of Cancer (23N) in the Northern Hemisphere.
• Tropic of Capricorn (23 °S) in the Southern Hemisphere.
•  Arctic Circle at 66 north of the equator.
• Antarctic Circle at 66° south of the equator.

### HEAT ZONES OF THE EARTH

The mid-day sun is exactly overhead at least once a year on all latitudes in between the Tropic of Cancer and the Tropic of Capricorn. This area, therefore, receives the maximum heat and is called the Torrid Zone. Why are lines of latitude also called parallels

The mid-day sun never shines overhead on any latitude beyond the Tropic of Cancer and the Tropic of Capricorn. The angle of the sun’s rays goes on decreasing towards the poles. As such, the areas bounded by the Tropic of Cancer and the Arctic Circle in the Northern Hemisphere, and the Tropic of Capricorn and the Antarctic Circle in the Southern Hemisphere, have moderate temperatures. These are, therefore, called Temperate Zones.  Why are lines of latitude also called parallels

Areas lying between the Arctic Circle and the North Pole in the Northern Hemisphere and the Antarctic Circle and the South Pole in the Southern Hemisphere, are very cold. It is because here the sun does not rise much above the horizon. Therefore, its rays are always slanting and provide less heat. Pole These are, therefore, called Frigid Zones (very cold).

### WHAT ARE LONGITUDES?

To fix the position of a place, it is necessary to know something more than the latitude of that place. You can see, for example, that Tonga Islands (in the Pacific Ocean) and Mauritius Islands (in the Indian Ocean) are situated on the same latitude (i.e., 20° S). Now, in order to locate them precisely, we must find out how far east or west these places are from a given line of reference running from the North Pole to the South Pole. Why are lines of latitude also called parallels

These lines of references are called the meridians of longitude, and the distances between them are measured in ‘degrees of longitude.’ Each degree is further divided into minutes, and minutes into seconds. They are semicircles and the distance between them decreases steadily polewards until it becomes zero at the poles, where all the meridians meet.

Unlike parallels of latitude, all meridians are of equal length. Thus, it was difficult to number the meridians. Hence, all countries decided that the count should begin from the meridian which passed through Greenwich, where the British Royal Observatory is located. This meridian is called the Prime Meridian. Why are lines of latitude also called parallels