Globe: Latitudes and Longitudes - Geography NCERT Notes For UPSC
Jan 18, 2023
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Important Parallels of Latitude
Heat zones of the Earth
Temperate Zone
Frigid zones
Longitude and Time
Interesting Facts
Important Parallels of Latitude
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 (23½° N) in the Northern Hemisphere.
- Tropic of Capricorn (23½° S) in the Southern Hemisphere.
- Arctic Circle at 66½° north of the Equator.
- Antarctic Circle at 66½° south of the Equator.
Heat zones of the Earth
- Torrid Zone:
The mid-day Sun is exactly overhead at least once a year on all latitudes between the Tropic of Cancer and the Tropic of Capricorn. These areas receive maximum heat thus called Torrid Zones.
Temperate Zone
- The mid-day Sun never shines overhead beyond the Tropic of Cancer and Tropic of Capricorn. The angle of the Sun’s rays goes decreasing towards the poles.
- This is the area between the Tropic of Cancer and Arctic Circle in the northern hemisphere and between the Tropic of Capricorn and Antarctic in the southern hemisphere.
- This area is having a moderate temperature.
Frigid zones
This is the area between the Arctic Circle and North Pole in northern hemisphere and Antarctic Circle and Southern pole in southern hemisphere. These are very cold areas and the Sun never shines above the horizon here.
What is the Longitude?
- In order to locate any place on Earth 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. 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 semi-circles and the distance between them decreases steadily pole wards until it becomes zero at the poles, where all the meridians meet. All meridians are of equal length.
- The Meridian which is passing through Greenwich, where the British Royal Observatory is located is called the Prime Meridian. Its value is “0” longitude and from it we count 180° eastward as well as 180° westward.
- 180° meridian divide the Earth into two equal halves, the Eastern Hemisphere and the Western Hemisphere.
- The longitude of a place is followed by the letter E for the east and W for the west. It is, however, interesting to note that 180° East and 180° West meridians are on the same line.
Longitude and Time
- The best means of measuring time is by the movement of the Earth, the Moon, and the planets.
- The shadow cast by the Sun is the shortest at noon and longest at sunrise and sunset.
- The Earth rotates 360° in about 24 hours, which means 15° an hour or 1° in four minutes.
- In India, the longitude of 82½° E (82° 30'E) is treated as the standard meridian.
Therefore the longitude and the latitude are very crucial in understanding about any place on globe or on Earth.
Interesting Facts
- Tonga Islands (in the Pacific Ocean) and Mauritius Islands (in the Indian Ocean) are situated on the same latitude.
- We can know the latitude of our place by measuring the angle of the Pole Star from our place.
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