Globe: Latitudes and Longitudes - Geography NCERT Notes For UPSC

Jan 18, 2023

Geography globe longitudes and latitudes NCERT notes

Globe is a true model (miniature form) of the Earth, which is very helpful to improve understanding of Earth’s shape and size such as the Earth is flattened at Poles and bulge at Equator (middle). Understand more about Globe and its Latitudes and Longitudes in this blog wherein we have covered all the essential topics pertaining to Globe such as Equator, Frigid Zones, etc. and upgrade your IAS exam preparation.

What is the Globe?

Globes may be of varying size and type – big ones, which cannot be carried easily, small pocket globes, and globe-like balloons, which can be inflated and are handy and carried with ease. The globe is not fixed. It can be rotated the same way as topspin or a potter’s wheel is rotated. On the globe, countries, continents, and oceans are shown in their correct size.
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 – the North Pole and the South Pole.
But in case of the real Earth, it has no such needle. It moves around its axis, which is an imaginary line.

What is the Equator?

The imaginary line running on the globe divides it into two equal parts. This line is known as the equator. The Northern Hemisphere is north of this line and the Southern Hemisphere is south of this line.
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 degrees latitude. Since the distance from the Equator to either of the poles is one-fourth of a circle round the Earth, it will measure ¼th of 360 degrees, i.e. 90°. Thus, 90 degrees north latitude marks the North Pole and 90 degrees south latitude marks the South Pole.
All parallels north of the Equator are called ‘north latitudes.’ Similarly, all parallels south of the Equator are called ‘south latitudes.’
The value of each latitude is, therefore, followed by either the word North or South. Generally, this is indicated by the letter ‘N’ or ‘S’.

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.

Important latitude and Heat 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.

Grids

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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