Geography of our planet, Earth

Earth is the third planet from the Sun. Its 70.8% of the area is covered with water in different forms ( oceans, seas, glaciers, rivers and lakes) and the remaining 29.2 % consists of continents and islands. The area with water is known as the hydrosphere and the one covered with the land is called the lithosphere. Earth is the fifth-largest planet in the solar system and it is originated from the Germanic word meaning “the ground”.

When studying the geography of planet Earth, there are two ways of dealing with it:

  • Physical Geography: It deals with studying all the physical features of the Earth including the study of oceans, landforms, minerals, soil, climate, natural resources, vegetation and animal life.
  • Human geography: This field studies the man-made features of planet Earth. It includes the study of population, its density and pattern, utilisation of land, means of transportation and communication, and types of materials for buildings. Human geography is further divided into two parts:

  Static human geography: Studying action of nature upon men

  Dynamic human geography: Studying action of men upon nature

In this article, we are focusing on physical geography. Now the structure of the Earth has four major components, the mantle, the crust, the inner core and the outer core. All these layers have a unique composition and physical properties. Movements in the mantle section are caused by the heat from the core and can also cause the plates to shift thus giving rise to volcanic eruptions and earthquakes. The crust covers less than 1 % of the Earth by mass and the mantle consists of 68% of Earth’s mass. The core of the Earth is mostly iron metal and made up about 31% of Earth’s mass. Because of this metallic core, the Earth has magnetic fields. The molten upper mantle material that can flow and also behaves plastically is called the asthenosphere. 

Earth’s atmosphere primarily consists of nitrogen (78%)  and oxygen(21%). Other than these, it consists of argon (0.9%) and carbon dioxide(0.03%) with small traces of other gases. Now, oxygen is considered most crucial for life on Earth. Most of the solar energy is absorbed by tropical regions.  The atmosphere provides a blanket for the Earth, it is made up of thin bands of air based on different temperatures. It protects us from the heat and radiation of the sun and contains the air that we breathe. Greenhouse gases play an important role in distributing heat in the atmosphere.

All the regions on Earth have their specified climate and for its determination, latitude is not the only essential factor, but elevation and proximity to oceans also plays an active role. Climate is considered a crucial factor in determining the occupancy of an area by man. The vegetation on Earth’s surface depends on the climate and also some other physical features such as the texture of soil and moisture supply.

Earth’s gravity enables it to interact with other objects in space such as moon, Earth’s only permanent natural satellite. This gravity increases as we move closer to the planet’s core and is maximum at the core-mantle boundary due to the high core material density. Whereas, on the surface of Earth, this force of gravity is inconsistent. The mountain ranges such as the Himalayas with a large concentration of mass have strong gravitational forces and oceans have the least gravitational forces.

References: